Friday
February 19, 1993
Part II
Environmental
Protection Agency
40 CFR Part 257 et al.
Standards for the Use or Disposal of
Sewage Sludge; Final Rules
-------
-------
Friday
February 19, 1993
U J
Part II
Environmental
Protection Agency
40 CFR Part 257 et al.
Standards for the Use or Disposal of
Sewage Sludge; Final Rules
-------
9248 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 257,403 and 503
[FRL-4203-3]
Standards for the Use or Disposal of
Sewage Sludge
AGENCY: Environmental Protection
Agency.
ACTION; Final rule.
SUMMARY: Under authority of Sections
405(d) and (e) of the Clean Water Act
(CWA), as amended (33 U.S.C.A. 1251,
et seg.), the Environmental Protection
Agency (EPA) is promulgating
regulations to protect puolic health and
the environment from any reasonably
anticipated adverse effects of certain
pollutants that may be present in
sowago sludge. The regulations establish
requirements for the final use and
disposal of sewage sludge in three
circumstances. First, the regulations
establish requirements for sewage
sludge when the sludge is applied to the
land for a beneficial purpose (including
sewage sludge or sewage sludge
products that are sold or given away for
use in home gardens). Second, the
regulations establish standards for
sludge when the sludge is disposed on
land by placing it on surface disposal
sites (including sewage sludge-only
landfills). Third, the regulations
establish requirements for sewage
sludge when incinerated. The standards
for each end use and disposal practice
consist of general requirements,
numerical limits on the pollutant
concentrations in sewage sludge,
management practices and, in some
cases, operational requirements. The
final rule also includes monitoring,
racordkeeping and reporting
requirements.
Standards apply to publicly and
privately owned treatment works that
generate or treat domestic sewage
sludge, as well as to any person who
uses or disposes of sewage sludge from
such treatment works. The rule requires
compliance with these standards as
oxpudiliously as possible but no later
than 12 months from the date the rule
is published, or within 24 months of
publication if construction of new
pollution control facilities is required to
comply with the regulations. The final
rule also includes conforming
amendments to 40 CFR parts 257 and
403.
DATES: The effective date is March 22,
1993. Additional comments and data
will be accepted until May 20,1993.
The incorporation by reference of
certain publications listed in this
regulation is approved by the Director of
the Federal Register as of May 20,1993.
ADDRESSES: This Notice is requesting
comments and data the Agency will
consider for Round Two part 503
rulemaking. Send written comments
and data described in this Notice to
Round Two Part 503 Sewage Sludge Use
and Disposal Rule; Comment Clerk;
Water Docket MC-4101; Environmental
Protection Agency; 401 M Street, SW;
Washington, DC 20460. Respondents are
also requested to submit an original and
3 copies of their written information.
Respondents who want receipt of their
information acknowledged should
include a self-addressed, stamped
envelope. All submissions must be
postmarked or delivered by hand, no
facsimiles (faxes) will be accepted.
A copy of the comments and
supporting documents cited in the
reference section of this Notice are
available for review at EPA's Water
Docket; 401M Street, SW.; Washington,
DC 20460. The Docket is located in
room L-102. For access to Docket
materials, call (202) 260-3027 between
9 a.m. and 3:30 p.m. for an
appointment. The EPA public
information regulation (40 CFR part 2)
provides that a reasonable fee may be
charged for copying.
FOR FURTHER INFORMATION CONTACT:
Further information on the part 503 rule
may be obtained by writing or calling
Dr. Alan Rubin, U.S. Environmental
Protection Agency, Office of Water,
Sludge Risk Assessment Branch (WH-
586), 401 M Street, SW., Washington,
DC 20460, (202) 260-1306. Information
on the availability of single copies of the
final rule, technical support documents,
and copies of the data, analyses and
models discussed in today's final rule is
provided in part XIV of SUPPLEMENTARY
INFORMATION.
SUPPLEMENTARY INFORMATION: The
preamble to this Notice is organized as
follows:
Overview
Part I: Generation, Use and Disposal of
Sewage Sludge
Part II: Federal and State Requirements
Part III: Selection of Pollutants Considered
for Regulation
Part IV: February 6,1989 Proposed Rule
Part V: November 9,1990 Notice of
Availability of Information and Data, and
Anticipated Impacts on Proposed Rule
Part VI: Risk Assessment Methodology
Part VII: Risk Management Approach
Part VIII: Exposure Assessment Methodology
and Other Risk Management Issues for
Sewage Sludge Use and Disposal
Practices for the Final Rule
Part IX: Selection of Pollutants for Regulation
Part X: Aggregate Risk Assessment for the
Final Part 503 Regulation
Part XI: Description of the Final 40 CFR Part
503 Regulation
Subpart A: General Provisions
Subpart B: Land Application
Subpart C: Surface Disposal
Subpart D: Pathogens and Vector
Attraction
Subpart E: Incineration
Part XII: Implementation of 40 CFR Part 503
Part XIII: Benefits and Cost of the
Amendments to Parts 257 and 403 and
the Final Part 503 Regulation
Part XIV: Availability of Technical
Information on the Final Rule
Part XV: Description of the Amendments to
40 CFR Parts 257 and 403
Overview
With the publication of today's rule,
EPA has now met its longstanding
obligation to promulgate regulations to
establish standards for the use and
disposal of sewage sludge. EPA's
undertaking required an unprecedented
effort to assess the potential for
pollutants in sewage sludge to affect
public health and the environment
through a number of different routes of
exposure. As a result, EPA's effort, an
enormously complex one, has required
it to address issues that affect many of
the Agency's other major regulatory
responsibilities. For example,
evaluation of the risks posed by
pollutants that may be present in sludge
applied to land required the Agency to
consider human exposure through
inhalation, direct ingestion of soil
fertilized with sewage sludge and
through consumption of crops grown on
this soil, among others. EPA also
assessed the potential risk to human
health through contamination of
drinking water sources or surface water
when sludge is disposed of on the land.
EPA also evaluated the potential effects
directly on crops, on cattle, on surface
water aquatic species and wildlife. EPA
also evaluated the effect of emissions
from sewage sludge incinerators on
human health. Thus, development of
the sewage sludge regulation had
obvious implications for Agency
activities under the Clean Air Act, the
Resource Conservation and Recovery
Act, the Toxic Substances Control Act,
the Comprehensive Environmental
Response, Compensation and Liability
Act and the Safe Drinking Water Act.
Development of this rule presented
the Agency with a number of specific
challenges in addition to those
associated with coordinating these
standards with other Agency programs.
Not the least of these was assessing the
potential for adverse effects on public
health and the environment from
pollutants in sludge. This is particularly
difficult with respect to non-human
health effects, given the limited
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9249
information available to the Agency in
this area. This evaluation was further
complicated by the fact that the
methods for evaluating non-human
health effects are less well-developed
than those the Agency has traditionally
relied on for evaluating human health
effects.
Nevertheless, EPA is confident that
the regulations it is promulgating today
adequately protect public health and the
environment from all reasonably
anticipated adverse effects, as required
by section 405 (d), for several reasons.
First, EPA has evaluated its regulations
for aggregate national health impact. As
explained in more detail below, even
given very conservative assumptions
that probably overstate exposure, there
are virtually no effects when sludge is
disposed of on the land or used as a soil
conditioner or fertilizer in compliance
with these rules. Further, even when
sludge is incinerated and the population
potentially exposed to the incinerator
emissions is greater, the effects are
small.
Second, use and disposal of sewage
sludge is not new in this country. In the
process of developing these regulations,
EPA reviewed the available scientific
and technical literature for information
on sewage sludge. That search did not
turn up any evidence that the use of
sewage sludge is causing any significant
or widespread adverse effects. While
anecdotal, this evidence tends to
confirm what EPA's risk assessment
review showed more scientifically.
Finally, the Agency's sewage sludge
assessment effort is not over. This is the
first stage of EPA's sewage sludge
regulatory program—"Round One." The
statute under which these regulations
are issued requires the Agency to
develop regulations in two steps and to
revise these regulations periodically if
additional information suggests the
need for regulation of other pollutants.
The Agency has committed to
identifying in May, 1993, the additional
pollutants it will consider for regulation
in "Round Two" and announcing its
schedule for completion of the second
stage effort. The Agency is comfortable
that the regulations promulgated here
are adequately protective because most
of the effects that these regulations are
designed to prevent are largely chronic,
not acute ones. Even in the unlikely
event that new information dictates
reconsideration of some of the
determinations on which EPA has based
its health conclusions for this rule, there
would be no adverse short-term human
health consequences since standards to
protect against chronic effects are well
below acute effects levels. Moreover, the
Agency is committed to an effort that
investigates many of the assumptions it
used in determining what levels of
pollutants in sewage sludge were
consistent with broad protection of
public health and the environment as
discussed below. Based on the results of
this study or any new information
showing an increased potential for
adverse effects on public health, the
Agency is prepared to move aggressively
to address any problems with sewage
sludge use should the evidence warrant.
Clean Water Act
Congress adopted the Clean Water Act
(CWA) to "restore and maintain the
chemical, physical, and biological
integrity of the Nation's waters."
Section 101(a), 33 U.S.C. 1251(a). To
achieve this goal, the CWA prohibits the
discharge of pollutants into navigable
waters except in compliance with the
statute. The CWA directs EPA to
promulgate regulations establishing
limits on the types and amounts of
pollutants discharged from various
industrial, commercial, and public
sources of wastewater.
Congress recognized that regulating
only those sources discharging effluent
directly into the nation's waters alone
would not sufficiently achieve the
CWA's goals. Consequently, the CWA
requires EPA to promulgate nationally
applicable pretreatment standards
which restrict pollutant discharges for
those who discharge wastewater
indirectly through sewers flowing to
publicly owned treatment works
(POTWs). Section 307 (b) and (c), 33
U.S.C. 1317 (b) & (c). Generally, these
national pretreatment standards are
designed to ensure that wastewaters
from direct and indirect industrial
dischargers are subject to similar levels
of treatment. In addition, POTWs are
required to implement local treatment
limits applicable to their industrial
indirect dischargers to satisfy any local
requirements. 40 CFR 403.5.
Direct dischargers must comply with
effluent limitations in National
Pollutant Discharge Elimination System
("NPDES") permits; indirect dischargers
must comply with pretreatment
standards. These limitations and
standards are established by regulation
for categories of industrial dischargers
and are based on the degree of control
that can be achieved using various
levels of pollution control technology.
In addition, pretreatment standards
must be established for those pollutants
which are not susceptible to treatment
by POTWs or which would interfere
with POTW operations. CWA Sections
301(b), 304(b), 306, 307 (bHd), 33
U.S.C. 1311(b), 1314(b), 1316, and 1317
(bHd).
POTWs receive wastewater from
industrial facilities, domestic wastes
from private residences, and run-off
from various sources that must be
treated prior to discharge. Treatment
results in an effluent that may be
discharged and a residual material,
sewage sludge. The sewage sludge,
usually more than 90 percent water, also
contains solids and dissolved
substances. The chemical composition
and biological constituents of the sludge
depend upon the composition of the
wastewater entering the treatment
facilities and the subsequent treatment
processes. Typically these constituents
may include volatile organics, organic
solids, nutrients, disease-causing
pathogenic organisms (e.g., bacteria,
viruses, and others), heavy metals and
inorganic ions, and toxic organic
chemicals from industrial wastes,
household chemicals, and pesticides.
Implementation of the CWA has
resulted in greater levels of treatment of
and pollutant removal from wastewater
before discharge to surface waters, and
the generation of large quantities of
residual sewage sludge as a by-product
of this treatment. Proper management of
ever-growing amounts of sewage sludge
is becoming increasingly important as
efforts to remove pollutants from
wastewater have become more effective.
In the United States, the quantity of
municipal sewage sludge has almost
doubled since the enactment of the
Clean Water Act in 1972. Municipalities
currently generate over 5.3 million dry
metric tons of wastewater sludge per
year, or approximately 47 pounds per
person per year (dry weight basis).
A POTW has a number of options to
dispose of sewage sludge, including
applying it to land, incineration,
disposing of it in a landfill, or selling it
to the public for use as a fertilizer or soil
nutrient. However, the composition of
the sludge can limit these choices.
One important avenue for sewage
sludge disposal is through beneficial use
and recycling projects. Sewage sludge is
a valuable resource. The nutrients and
other properties commonly found in
sludge make it useful as a fertilizer and
a soil conditioner. Sludge has been used
for its beneficial qualities on
agricultural lands, in forests, for
landscaping projects, and to reclaim
strip-mined land.
At the same time, in some situations,
disposal of sewage sludge may present
an environmental concern because of
contamination by harmful pollutants.
Greater focus on surface water toxics
control, as well as Resource
Conservation and Recovery Act (RCRA)
provisions such as the ban on land
disposal of certain hazardous wastes
-------
9250 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(section 3004(d)) and the exclusion of
discharges into municipal sewers from
RCRA requirements (section 1004(27)),
may result in increased volumes of toxic
and hazardous pollutants that reach
POTWs and consequently may
adversely affect sludge quality when
these pollutants are removed from the
waslowater.
Proper disposal of sewage sludge is
important because contaminated or
improperly handled sludge can result in
pollutants in the sludge re-entering the
environment, and possibly
contaminating a number of different
media through a variety of exposure
routes. Further, improper sludge
management could lead to
environmental degradation of land and
air. Failure to dispose of sludge properly
or contaminated sludge could also have
adverse effects on surface and ground
water and wetlands, as well as human
health. For example, sewage sludge
disposed on land where there is
minimal depth to ground water is of
concern because contaminants in the
sludge may leach out and reach an
existing or potential potable water
source. Concern for air quality
necessitates proper controls over sludge
incineration. The interrelationship
among those media requires a tightly
coordinated, comprehensive approach
to encourage the beneficial use of sludge
and to avoid creating environmental
loopholes, thereby helping to assure that
solving problems in one media will not
create problems for another.
Section 405 of the Clean Water Act
The CVVA, as enacted in 1972,
addressed sewage sludge use and
disposal in only one limited
circumstance: \vhen the use or disposal
posed a threat to navigable waters.
Thus, section 405(a) of the Act
prohibited the disposal of sludge if it
would result in any pollutant from the
sludge entering navigable waters unless
in accordance with a permit issued by
EPA. In 1977, Congress amended
section 405 to add a new section 405 (d)
which required EPA to develop
regulations containing guidelines for the
use and disposal of sewage sludge.
These guidelines must: (1) Identify uses,
for sludge including disposal; (2)
specify factors to be taken into account
in determining the methods and
practices applicable to each of these
identified uses; and (3) identify
concentrations of pollutants that would
interfere with each use.
In 1987, Congress amended section
405 and for the first time set forth a
comprehensive program for reducing
the potential environmental risks and
maximizing the beneficial use of sludge.
Amended section 405(d) established a
timetable for the development of the
sewage sludge use and disposal
guidelines. H. Rep. No. 1004, 99th Cong.
2d. Sess., 158 (1986). The basis of the
program Congress mandated to protect
public health and the environment is
the development of technical
requirements or standards for sewage
sludge use and disposal and the
implementation of these standards, in
part, through a permit program.
Under section 405(d), EPA must first
identify, based on available information,
toxic pollutants which may be present
in sewage sludge in concentrations
which may affect public health and the
environment. Next, for each identified
use or disposal method, EPA must
promulgate regulations that specify
acceptable management practices and
numerical limitations for sludge that
contains these pollutants. These
regulations must be "adequate to protect
human health and the environment
from any reasonably anticipated adverse
effect of each pollutant." Section
405(d)(2)(D). The statute requires EPA to
promulgate sewage sludge regulations in
two stages and periodically to review
these regulations for the purpose of
identifying additional toxic pollutants
for regulation.
After the technical standards have
been promulgated, section 405 directs
that any permit under section 402 of the
CWA (NPDES permits) issued to a
POTW or any other treatment works
treating domestic sewage must include
conditions to implement the technical
standards unless these conditions are
included in a permit issued under:
Subtitle C of the Resource Conservation
and Recovery Act; Part C of the Safe
Drinking Water Act; the Marine
Protection, Research, and Sanctuaries
Act or the Clean Air Act; or under State
permit programs approved by EPA,
where EPA determines that such
programs assure compliance with any
applicable requirements of section 405.
33 U.S.C. 1345(f)(l). Section 405 also
provides that EPA may issue permits
that implement the sludge requirements
to treatment works that are not subject
to NPDES permitting or to any of the
other enumerated programs or approved
State programs. 33 U.S.C. 1345(f)(2).
These permits are referred to in this
preamble as "sludge-only" permits.
Congress provided little guidance for
the Agency in carrying out its broad
mandate to protect public health and
the environment. For example, Congress
did not speak directly or provide the
Agency guidance about how to interpret
certain key phrases in the statute.
Consequently, the Agency in
determining appropriate sludge
standards has faced a number of
difficult policy issues. The Agency has
addressed the following issues in
determining what standards adequately
protected public health and the
environment from pollutants in sewage
sludge when used or disposed,
Regulatory Issues
In determining what standards
adequately protected public health and
the environment from pollutants in
sewage sludge when used or disposed
of, the Agency needed to address a
myriad of issues including the
following:
Scope of the Regulation. Different
types of sewage sludge are generated
and there are different ways of using or
disposing of it. Given the different types
of sludge that are generated, which
types should the Agency regulate? Of
the methods used by communities to
dispose of their sewage sludge, which
types of methods should the Agency
regulate?
Pollutant Coverage. On what basis
should the Agency select the pollutants
(metals, pesticides, organic
contaminants, pathogenic organisms)
which are regulated in today's rule?
Pathways of Exposure. What media
(air, water, soil) transport the pollutants
in sewage sludge into and through the
environment?
Target Organisms. What individuals
or groups of individuals, plants, or
animals are most likely to be affected by
the pollutants in sewage sludge?
Models. How will the Agency
simulate the movement of the pollutants
in sewage sludge into and through the
various environmental media to the
target organisms?
Type of Risks. What are the potential
human health and environmental risks
posed by the use or disposal of sewage
sludge (e.g., breathing air around a
sewage sludge incinerator, drinking
water from a well near a monofill, eating
food grown on soil to which sludge has
been applied, plants growing on sludge-
enriched soil, etc.) that the Agency
should examine?
Effect Levels. At what concentrations
does a pollutant adversely affect human
health and the environment? Pollutants
from sewage sludge potentially may
move through the environment to reach
a plant, animal, or human. Plant, animal
and human systems may "respond" to
the presence of the pollutant. That is,
biological systems within the plant,
animal or human, may exhibit
variations from normal conditions. At
what point does this variation constitute
an adverse effect? Must the standards
protect against all adverse effects or
only significant adverse effects? What
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9251
are the effects the standards should be
designed to prevent (e.g., increased risk
of developing cancer or hypertension,
phytotoxicity, animal toxicity)?
Acceptable Level of Risk. The statute
requires that the sludge regulations
"adequately protect human health and
the environment from reasonably
anticipated adverse effects." What level
of risk adequately protects human
health and the environment? By
requiring "adequate protection" of
public health and the environment did
Congress intend to leave to EPA's
discretion the determination of what
adverse effects public health and
environmental protection required? Is a
consideration of whether the effects are
widespread, particularly with respect to
non-public health effects, part of the
determination of what constitutes
adequate protection?
Background Pollutant Levels. What
are the sources of pollutant exposure
other than sludge (e.g., lead from
gasoline or from water supply pipes,
etc.)?
Uncertainties. How should the
Agency measure and account for the
unavoidable uncertainties in its
analyses (e.g., use conservative
assumptions, add a margin of safety)?
Types of Effects to be Evaluated.
Should the Agency evaluate the human
health and environmental effects on the
most exposed target organisms
(individual, plant, or animal) or should
the Agency also examine the incidence
of adverse effects on the total
population associated with sewage
sludge use or disposal?
Pollutant Limits. Should a single
pollutant limit be established for all use
or disposal practices or should a
separate pollutant limit be established
for each use or disposal method?
Form of the Pollutant Limits. How
should the pollutant limits be expressed
(e.g., a limitation on pollutant
concentrations in sewage sludge, a
limitation on pollutant loading rates to
land, a limitation on pollutant emission
rates, etc.)?
Regulatory Pesponsibility. Who
should be responsible for meeting the
requirements in the rule (end user,
treatment work)?
Impacts. Who is affected by the rule?
What are the benefits and costs of the
rule?
Since 1984, the Agency has been
conducting an extensive information-
gathering and analytical program to
support the development of today's
regulation. Subsequent to the 1987
amendments to the CWA, the Agency
redoubled its efforts. This preamble, the
technical support documents, and
related analyses of the regulation's
impact are the product of that effort and
explain the basis for the determinations
the Agency has made in establishing
these standards.
Fundamental Regulatory Principles
The fundamental assumptions
underlying today's final rule are
discussed below:
Control Sewage Sludge Quality
Section 405 (d) of the CWA directs the
Agency to control the quality of sewage
sludge by establishing limits for
pollutants in sludge applicable to
methods of use or disposal. Preventing
the contamination of sewage sludge
before it is used or disposed of is more
equitable than requiring others to
contain the contaminated sewage sludge
or to deal with the consequences. When
it is not feasible for the Agency to set
pollutant limits, section 405(d)(3)
authorizes EPA to establish a design or
equipment standard, management
practice, or operational standard or
combination of these in lieu of
numerical limitations. This is the
approach EPA took in the criteria
promulgated for municipal solid waste
landfills (MSWLFs). There, EPA
adopted a containment approach rather
than numerical limitations for solid
waste, including sewage sludge
disposed of in MSWLFs, in part because
of the infeasibility of developing and
enforcing numerical limitations for
mixtures of sewage sludge and other
solid waste materials disposed of in
MSWLFs (56 FR 50978, October 9,
1991).
By setting limits on sewage sludge
quality, this regulation creates
incentives for treatment works to
generate less contaminated sewage
sludge. Treatment works with sewage
sludge that does not meet the sludge
quality conditions under the standards
for a use and disposal practice must
clean up the influent (e.g., strengthen
the pretreatment programs), improve the
treatment of sewage sludge (e.g., reduce
the densities of pathogenic organisms),
or select another use or disposal
method.
Emphasize Waste Reduction and the
Beneficial Reuse of Sewage Sludge
Achieving desired national levels of
environmental quality depends on the
reduction and elimination of the
substantial volumes of waste and
wastewater generated at home and at
work. Without a significant reduction in
these volumes (e.g., by home
composting food scraps rather than
putting them down a garbage disposal),
and a corresponding reduction in the
residual from wastewater treatment
(sewage sludge is also often referred to
as "biosolids") that must then be either
used or disposed of, attaining these
goals is severely hampered.
EPA's policy (i.e., the 1984 Beneficial
Reuse Policy and the 1991 Interagency
Policy on Beneficial Use of Sewage
Sludge) of strongly supporting the
beneficial reuse of sewage sludge is
closely linked to its objective of
reducing the volume of waste generated.
The term biosolids has been used to
distinguish sewage sludge that has been
treated and can be beneficially recycled.
Improving the productivity of our land
using the soil conditioning properties
and nutrient content of sewage sludge
has human health and environmental
advantages beyond those that are
directly associated with applying
sewage sludge to the land. Secondary or
related benefits of reusing sewage
sludge result from a reduction in the
adverse human health effects of
incineration, a decreased dependence
on chemical fertilizers, a reduction in
the emissions associated with
incineration that may contribute to the
"greenhouse effect" and a reduction in
fuel or energy costs associated with
incineration. In finalizing the rule, the
Agency carefully considered, and
placed heavy emphasis on, those
approaches that supported its policy of
beneficial reuse.
Preserve a Local Community's Choice of
a Disposal Practice
Although the Agency prefers local
communities to use their sewage sludge
for its beneficial properties rather than
simply disposing of it, EPA's
responsibility is to set standards for
each practice that are adequate to
protect public health and the
environment. While the choice of a use
or disposal practice is reserved to local
communities by section 405(e) of the
CWA, protection of public health and
the environment, where risks are
significant, dictate stringent pollutant
limits. One result is that in certain cases
communities may be unlikely to meet
the limits the Agency has promulgated.
Base the Rule on Minimizing Risks to
Individuals and to the Population as a
Whole
In developing today's rule, the
Agency evaluated the effect of a
pollutant on a highly exposed
individual, plant, or animal (HEI) and
on populations at higher risk. It also
examined regulatory options that would
have resulted in a rule based on
aggregate incidence analyses only (the
effect on the whole population), on the
most exposed individual, plant, or
animal (MEI) analyses only, and a rule
-------
9252 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
based on a combination of aggregate and
MEI analyses. Today's final rule uses an
HEI analysis supported by an aggregate
risk assessment on higher risk
populations or special subpopulations
(e.g., children) to ensure protection of
public health and the environment.
Promulgate Reasonable Standards
Section 405(d)(2)(D) of the CWA
requires the Agency to establish
standards adequate to protect public
health and the environment from any
reasonably anticipated adverse effects of
each pollutant found in sewage sludge.
In establishing standards, the Agency
examined the effect of long-term
pollutant exposure and circumstances
thai could: (1) Increase the toxicity and
potency of a pollutant in the
environment, (2) speed the movement of
a pollutant into and through the
environment, and (3) intensify the
adverse effect that the pollutant may
have on human health or the
environment.
This approach is used throughout the
rule but it does not protect against every
conceivable combination of adverse
conditions. In taking such an approach,
the Agency recognizes that some risks
may not have been fully evaluated and
that some risks may remain after
regulation. For example, the Agency
used the average background value of
metals in agricultural soils for applying
sovvage sludge to agricultural lands and
assumed that users of sewage sludge
products, such as compost, would
follow simple label instructions. EPA
oxpocts that few, if any, individuals will
receive higher doses of a pollutant than
the doses used to establish the
standards. Therefore, the Agency has
determined that today's rule meets the
statutory directive that the standards
protect against reasonably anticipated
adverse effects of the pollutants. EPA
concluded that adequate protection of
public health and the environment did
not require the adoption of standards
designed to protect human health or the
environment under exposure conditions
that are unlikely and where effects were
not significant or widespread.
Promulgate an Implementable Rule
The final rule balances the flexibility
associated with site-specific analyses
against the simplicity of national
numerical limits and self-implementing
regulations. A rule that allows
exceptions for every conceivable
contingency would prove difficult to
understand. Moreover, implementation
of such a rule would require an
unwarranted commitment of the
Agency's limited resources without any
offsetting increased benefits to public
health or the environment. Therefore,
the limited exceptions to national
pollutant limits are restricted to
circumstances in which site-specific
conditions may make a significant
difference in the pollutant limits
without any compromise to public
health and environmental protection.
In those cases where site-specific
conditions are appropriate, persons
disposing of sewage sludge may use
EPA approved models and recalculate
numerical pollutant limits for sewage
sludge disposed of at their site. The
modeling analysis, supporting
information and recalculated numerical
limits are to be submitted to the
permitting authority for approval, and if
approved, become the numerical limits
for sludge quality disposed of at the site.
Section 405 (e) of the CWA requires
any person that uses or disposes of
sewage sludge generated by a treatment
works to comply with part 503
standards. Realistically, the Agency
cannot issue permits to every user of
sewage sludge. Therefore, primary
responsibility, and liability, is placed on
treatment works for ensuring that
sewage sludge is disposed in accordance
with the rule's requirements. The final
part 503 rule is designed to be self-
implementing, and therefore, clearly
spells out how the requirements apply
to persons using or disposing of sewage
sludge. When sewage sludge or sewage
sludge products are sold or given away
to the general public, sewage sludge
must generally meet higher standards of
quality. However, the national limits
were not designed to protect the public
against every conceivable misuse of the
product that is distributed and
marketed. Rather, the rule assumes that
simple instructions on proper use will
be followed.
Coordinate With Other Programs
The use and disposal of sewage
sludge affects air, soil, and water. In
preparing the final rule, the Agency
carefully examined the requirements of
other media programs and media-
specific statutes. Where possible for
consistency, the Agency used the tools
and standards developed under these
other programs. For example, the air
models used in developing the limits for
incinerating sewage sludge are similar
to the models used under EPA's air
program. The pollutant limit for
incinerating sewage sludge containing
lead is designed to be consistent with
the National Ambient Air Quality
Standard (NAAQS) for lead. This
principle is followed throughout the
rule. As another example, when the
pollutant limits are designed to protect
ground water, the Agency used the
drinking water standards (maximum
contaminant levels—MCLs), where
available. Further, when protecting
surface water, the Agency used the
Water Quality Criteria developed for
individual pollutants. In some cases,
Agency regulatory standards are
undergoing revision. If a new standard
is promulgated, the numerical pollutant
limit for a use or disposal practice will
be revised in later rulemakings.
Expand the Standards Later
The scope of the part 503 standards is
necessarily constrained by the adequacy
of information on sewage sludge
pollutants and means of use or disposal.
However, rather than wait for more
complete information in order to
promulgate all-inclusive regulations, the
Agency is promulgating standards for
those pollutants and use or disposal
practices for which sufficient
information exists. The Agency may
expand and refine these standards in
future rulemakings. Section 405
specifically contemplates that the
Agency will issue these standards in
stages and revise them periodically.
To remedy information gaps, the
Agency conducted the National Sewage
Sludge Survey (NSSS) which gathered,
among other things, additional
information on the pollutants in sewage
sludge, how sludge is used and
disposed, and information on POTW
management of sludge. See, 55 FR
47210 (November 9,1990). Furthermore,
in cooperation with other Agency
offices and outside expert reviewers,
EPA has gathered data on the movement
of certain pollutants into and through
the environment (e.g., cadmium),
refined and expanded its modeling
capability for specific pollutants or
disposal practices (e.g., surface disposal
sites), supplemented its information on
other disposal practices (e.g., sewage
sludge incinerators), and further
examined the characteristics of
domestic septage. Sewage sludge
pollutants and methods of use or
disposal not covered by today's final
rule are candidates for coverage under
subsequent phases of the part 503
rulemaking process as adequate data are
developed.
In addition, EPA had experts from
both inside and outside the Agency
review the scientific and technical bases
of the rule. This review included the
EPA Science Advisory Board, the
Cooperative State Research Service, the
Regional Research Technical Committee
(sometimes called the W-170
committee), representatives of
academia, and other scientific/technical
bodies with experience in the areas
covered by the rule. With the additional
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9253
data and the scientific and technical
review, the Agency was able to expand
and refine the standards for today's final
rule.
The preamble summarizes the major
scientific peer review and public
comments and provides the Agency's
response and actions taken in
developing today's final part 503 rule. A
complete description of all the public
comments is provided in Reference No.
109. Information on this and other
documents used in developing the final
part 503 regulation may be found in Part
XIV—Availability of Technical
Information on the Final Rule.
Coverage of Today's Rule and the
Round Two Rule
Today's rule establishes standards for
those pollutants and sludge use or
disposal methods for which the Agency
had sufficient information to establish
protective numerical limits,
management practices, and other
requirements. The Agency recognizes
that today's rule may not regulate all
pollutants in sewage sludge that may be
present in concentrations that may
adversely affect public health and the
environment.
Section 405 (d) of the CWA
specifically contemplates a phased
approach to establishing numerical
limits for sewage sludge pollutants.
Moreover, section 405(d)(2)(D) of the
CWA provides that "(f)rom time to time,
but not less often than every 2 years, the
Administrator shall review the
regulation * * * for the purpose of
identifying additional toxic pollutants
and promulgating regulations for such
pollutants * * *." EPA will be using
data from the NSSS to identify
additional pollutants in sewage sludge
that may interfere with the safe use or
disposal of the sludge for a second
round of rulemaking (Round Two).
For the NSSS, EPA analyzed sewage
sludge samples for 419 toxic pollutants.
Many of these pollutants were
undetected in the samples, infrequently
detected or present at levels below
detection limits. Consequently, the first
step in the process of identifying what
additional pollutants EPA may regulate
in Round Two is to determine what
pollutants are present in sludge in a
sufficient number of samples or at
concentrations that warrant further
examination for national regulation.
EPA statisticians have now reviewed the
analytical data and completed their
initial screening assessment for each
pollutant by frequency and level of
occurrence.
The next step with respect to Round
Two will be review of the scientific
literature for toxicity, fate, effect and
transport information on the pollutants
identified by the initial statistical
screening. EPA will use data from the
scientific literature on the adverse
human health and environmental effects
of these pollutants to calculate pollutant
concentrations in sludge that would be
associated with the identified adverse
effects. Through a comparison of the
calculated sludge levels associated with
adverse effects with the NSSS screening
data on actual level and frequency of
occurrence, EPA can make a
preliminary determination of the
pollutants that it should propose for
regulation.
If, based on the results of the exposure
assessment models, the pollutant
presents an unreasonable human health
or environmental risk, the Agency
would propose numerical limits or other
standards (if numerical limits are
infeasible or unenforceable) for the
pollutant appropriate to a particular
method of use or disposal.
Summary of the Final Rule
Today's rule establishes standards for
the final use or disposal of sewage
sludge when the sewage sludge is
applied to agricultural and non-
agricultural land (including sewage
sludge and sewage sludge products sold
or given away—described in the
proposed rule as distributed and
marketed sludge), placed in or on
surface disposal sites, or incinerated.
The rule does not apply to the
processing of sewage sludge before its
ultimate use or disposal. In addition,
EPA, in this rule, is not specifying
process operating methods or
requirements for sludge entering or
leaving a particular treatment process.
EPA has not established standards in
this rule for sewage sludge that is
disposed with municipal solid waste in
MSWLFs or that is used as a cover
material at MSWLF sites. Under the
joint authority of sections 4004 and
4010 of RCRA and section 405(d) of the
CWA, the Agency has adopted
requirements for MSWLFs that apply to
sewage sludge that is placed in these
landfills. The disposal of sewage sludge
in MSWLFs is regulated under 40 CFR
part 258 (see, 56 FR 50978, October 9,
1991). The Agency adopted this
approach for reasons explained in more
detail below. Treatment works using a
MSWLF to dispose of their sewage
sludge must ensure that their sewage is
non-hazardous and passes the Paint
Filter Liquid Test. If these requirements
are met, treatment works will be in
compliance with section 405(e) of the
CWA.
The standards also do not apply to
sewage sludge that is co-incinerated
with large amounts of solid waste (see,
56 FR 5507, February 11,1991).
However, the standards established in
the rule do apply to sewage sludge that
is incinerated in a sewage sludge
incinerator with incidental amounts of
solid waste used as an auxiliary fuel
(i.e., 30 percent or less solid waste by
weight).
The rule applies to sewage sludge that
is generated or treated by publicly
owned and privately owned treatment
works treating domestic sewage and
municipal wastewater. The rule does
not apply to domestic sewage that is
treated along with industrial wastewater
by privately owned industrial facilities.
The Agency has the authority under
section 405(d) of the CWA to regulate
industrial sludges with a domestic
sewage component, and it plans to
consider regulating these sludges in
future part 503 rulemakings. However,
until the Agency develops part 503
regulations to cover industrial sludges
produced by privately owned facilities
from the treatment of industrial
wastewater with a domestic sewage
component, those sludges (as well as
non-hazardous industrial sludges
without a domestic sewage component)
will be regulated under 40 CFR part 257.
The regulations promulgated here
today do not establish disposal ,
standards for sewage sludge that is
determined to be hazardous under
procedures in appendix II of 40 CFR
part 261. Hazardous sewage sludge must
be disposed of in compliance with the
hazardous waste regulations in 40 CFR
parts 261-268. Compliance with these
requirements will constitute compliance
for purposes of section 405. Also,
sewage sludge found to contain 50 ppm
or more of PCBs is excluded from this
rule. Sewage sludge with 50 ppm or
more of PCBs must be disposed of
according to the requirements
established in 40 CFR part 761.
Similarly, while EPA has not
established standards the disposal of
PCB-contaminated sludge, a disposer
complying with 40 CFR part 761 would
not violate section 405.
Finally, no standards are established
for the ocean disposal of sewage sludge
regulated by the Marine Protection,
Research, and Sanctuaries Act
(MPRSA). The Ocean Dumping Ban Act
of 1988, Public Law 100-688, amended
MPRSA to prohibit any person from
dumping sewage sludge into ocean
waters after December 31,1991. In
addition, Congress limited ocean
dumping during the interim period to
those who were authorized as of
September 1,1988, to dump either
under an MPRSA permit or a court
order. Further, Congress prohibited
-------
9254 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
dumping after August 15,1989, unless
an MPRSA permit had been obtained by
that time. All remaining communities
that dumped their sewage sludge in the
ocean ceased dumping at the end of
June, 1992.
Tho rule includes specific numerical
limits (or equations for calculating these
limits) for 10 pollutants when sewage
sludgo is used or disposed by one or
more methods. Not every pollutant is
regulated under each practice. EPA
developed these numerical limits by
using exposure assessment models
designed to protect individuals, plants,
animals or other organisms potentially
at greater risk from pollutants in sewage
sludge. In the case of sewage sludge that
is incinerated, in addition to numerical
limits, the Agency is also establishing
an operational standard for total
hydrocarbons rather than for individual
organic pollutants.
The numerical limits derived from the
exposure assessment models are
designed to protect public health or the
environment from reasonably
anticipated adverse effects. These
models incorporated well-established
measures of human health or
environmental protectiveness as their
design end-point. Thus, EPA based its
environmental assessment on human
health or environmental criteria already
published or promulgated by the
Agency, on human health criteria
developed by the Agency, or on plant
and animal toxicity values published in
the scientific literature. Thus, for
example, when sewage sludge is
incinerated, the numerical limit for lead
is based on the NAAQS for lead. When
tho objective is to protect sources of
drinking water, pollutant limits were
developed which would ensure that
drinking water MCLs established under
the Safe Drinking Water Act are not
violated. When the objective is to
protect surface water, Water Quality
Criteria issued under section 304 of the
Clean Water Act are used. In its
exposure assessment, if the Agency had
not published or promulgated criteria
for specific pollutants, EPA evaluated
non-cancer human health risks from
pollutant exposure using reference
doses. EPA evaluated cancer risk using
cancer potency factors—so-called Oj. or
Q* values—listed in the Agency's
computerized Integrated Risk
Information System (IRIS). In all cases,
EPA used cancer potency values
corresponding to an incremental
carcinogenic risk level of lxio~4 to
evaluate the risk from pollutants found
in sewage sludge. (The exposure level of
a pollutant associated with a 1x10 ~4
cancer risk implies that one additional
cancer case will occur in a population
of 10,000 exposed at that level for 70
years.) For purposes of establishing the
numerical limits for incinerators
promulgated today, EPA did, however,
evaluate exposure at different
incremental cancer risk levels (i.e.,
lxlO~4 through 1x10 ~s). In the case of
human health, the final limits for
pollutants in sewage sludge ensure that
the use and disposal of sludge does not
result in ambient concentrations of the
regulated pollutants that exceed an
incremental carcinogenic risk level of
lxlO~4.
For sewage sludge disposed of in or
on surface disposal sites (including
sludge-only landfills, often referred to as
"monofills") or incinerated, treatment
works may submit modeling and data
analyses (for certain physical
parameters related to the site) used to
recalculate site-specific numerical
limits. The permitting authority will
review and approve the treatment
works' site-specific modeling and data
analyses used to recalculate numerical
limits using EPA-approved exposure
assessment methods. Since these
recalculated numerical limits are based
on EPA-approved models and the same
human health and environmental
criteria as the national numerical limits,
the recalculated limits will also
adequately protect human health and
the environment from reasonably
anticipated adverse effects of pollutants
found in sewage sludge.
EPA has also acted today to amend 40
CFR part 403 to authorize treatment
works to authorize removal credits for
certain pollutants. The amendment lists
those pollutants for which removal
credits may be authorized. In addition
to the pollutants for which specific
numerical limits are established,
removal credits may be available for
pollutants that EPA evaluated for
regulation and for which EPA decided
not to establish numerical limits.
In the case of sewage sludge applied
to the land or disposed of in or on
surface disposal sites, the final rule
establishes requirements for pathogenic
organisms or pathogenic indicator
organisms such as fecal coliform. The
rule also includes requirements for
destroying or reducing those
characteristics of sewage sludge that
attract birds, insects, rats and other
animals (so-called "vectors"). "Vector"
exposure to the pathogenic organisms in
sludge can cause transfer of pathogens
(and consequently spread disease) from
these disease vectors to humans. The
final rule consequently requires
measures for reducing the attraction of
vectors to sewage sludge. These
measures could include destruction of
the odor causing properties of sludge
that lure insects and animals.
Supplementing the numerical
pollutant limits are management
practices and general requirements to
protect human health and to prevent
gross abuse of the environment. In the
case of small quantity sludge that is sold
or given away in a bag or other
container, the rule requires the
treatment works (or other person, if
different from the treatment works) to
label the product. The label is to
provide instructions on properly using
the product.
The rule also includes monitoring,
recordkeeping, and reporting
requirements. The frequency with
which sewage sludge is to be monitored
depends on the quantity of sludge used
or disposed by a treatment works. The
pollutants for which treatment works
must monitor their sewage sludge
similarly depend on the use or disposal
method selected. The recordkeeping and
reporting requirements are also specific
to a particular method of use or
disposal.
The final rule is expected to cover
nearly 35,000 entities. These entities
include: primary treatment POTWs,
secondary and advanced treatment
POTWs, privately owned treatment
works, Federally owned treatment
works, and domestic septage haulers.
Based on the NSSS, this rule is
expected to affect approximately 6,300
of the 12,750 secondary, advanced, and
primary POTWs that use one or more of
the disposal practices included in the
rule. These 6,300 facilities generate or
treat approximately 60 percent of the
sewage sludge produced in the United
States. Of the remaining POTWs, an
estimated 2,700 dispose of their sewage
sludge (34 percent of the total sewage
sludge generated) in MSWLFs that are to
be regulated under 40 CFR part 258 (56
PR 50978, October 9, 1991). The
remaining 3,750 POTWs use other
disposal practices not covered in either
this regulation or the MSWLF rule. In
some cases, compliance with the
requirements for those other practices
constitutes compliance with 405 (d) of
the CWA.
The aggregate risk assessment
estimates that current use and disposal
practices contribute from less than one
up to five cancer cases annually, with a
lifetime cancer risk to a highly exposed
individual ranging from 6x10~4 for land
application and surface disposal of
sludge and from 6xlO~4 to 7xlO~3 for
incineration. The other health effects
associated with sewage sludge use and
disposal are primarily related to lead
exposure and result in approximately
2,000 individuals who exceed a
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9255
threshold blood lead level associated
with adverse health effects and 700
instances of hypertension in adult males
or diminished learning capacity in
children. The Agency estimates that the
rule reduces cancer cases by 0.09—0.7,
exceedences of lead adverse health
threshold by 600-2,000 and instances of
lead cases by 90-600.
For the purpose of the regulatory
impact analysis, the Agency estimated
that approximately 130 of the 6,300
affected POTWs may have sewage
sludge which does not meet the
numerical limits. This estimate does not
take into consideration the possibility
that some POTWs may come into
compliance by using site-specific data to
calculate new numerical limits and by
imposing more stringent pretreatment
requirements on their industrial
dischargers. The Agency estimates
annual compliance costs of $45.9
million or an increase of less than $1
annually for each household served by
the affected POTWs. The total annual
incremental compliance costs include
costs for sludge monitoring,
management practices, and in some
cases, incremental costs of changing a
practice for POTWs that fail to meet the
numerical pollutant limits for a practice.
The technical support documents,
aggregate human health risk analyses,
the regulatory impact analyses, and the
preamble discuss die factors that EPA
considered, the data and comments it
evaluated, and the determinations that it
made in developing the final rule. The
preamble summarizes this information
in 15 parts.
Part I briefly describes the generation,
volume, and constituents of sewage
sludge and the factors that communities
must consider in using or disposing of
the sewage sludge that results from the
treatment of domestic sewage and
municipal wastewater. Part I also
identifies the ways in which
communities commonly use or dispose
of their sewage sludge, the benefits of
reusing sewage sludge, and the risks
associated with its disposal.
Part II lists existing Federal and State
requirements for the use and disposal of
sewage sludge including the
relationship of the existing requirements
to today's rule.
In part III, the preamble begins to
describe how the Agency developed the
final rule. Initially, the Agency selected
pollutants most likely to interfere with
the safe use or disposal of sewage sludge
and then refined the list of pollutants
based on the availability of information
on the toxic effects of the pollutants. In
refining the initial list of pollutants, the
Agency simulated the movement of
pollutants into and through the
environment with a series of exposure
assessment models to determine the
concentrations of pollutants reaching an
individual, plant, or animal.
In part IV, the preamble briefly
describes the February 6,1989 proposed
rule.
In part V, the preamble discusses the
Agency's effort to develop current data
on sewage sludge quality and an
accurate characterization of current
methods of sludge use and disposal
employed by treatment works. This part
describes EPA activity following the
proposal including efforts to obtain
additional information on sewage
sludge incinerators and domestic
septage. This part also describes the
November 9,1990 Notice of Availability
of Information and Data, and
Anticipated Impacts on Proposed
Regulations.
Parts VI and VII discuss the
alternative regulatory approaches and
public comments the Agency
considered in developing the risk
assessment methodology for the final
rule. Included in the discussion are the
factors on which the Agency based its
risk management decisions and its
selection of a risk assessment
methodology that would adequately
protect public health and the
environment.
Part VIII discusses the proposed
exposure assessment methodology and
public comments the Agency
considered in developing the exposure
assessment methodology for the final
rule. This part also describes the (1)
critical exposure assessment models,
pathways, parameters and assumptions;
(2) other risk management issues
evaluated by the Agency; and (3) the
human health and environmental
criteria used to establish numerical
limitations for each sewage sludge use
and disposal practice.
Part IX describes the criteria the
Agency used to select pollutants for
regulation in the final part 503 rule.
Prior to selecting its approach for
establishing standards for a particular
use or disposal practice, the Agency
examined the aggregate human health
effects on highly exposed individuals
and the nation from the use and
disposal of sewage sludge. The methods
used to conduct these analyses and the
results are described in part X.
Part XI describes, in separate
subparts, the requirements that apply to
the use and disposal of sewage sludge.
In addition, part XI describes the
requirements for septage use and
disposal, the pathogen and vector
attraction requirements; and the
monitoring, record-keeping and
reporting requirements.
Part XII briefly discusses the
implementation of the final rule through
Federal and State permit programs and
the self-implementing nature of the
regulations. Under a separate
rulemaking, the Agency promulgated
State program management
requirements and changes in the
National Pollutant Discharge
Elimination System permitting
requirements (54 FR 18716, May 2,
1989).
The benefits, costs, and regulatory
impact of the rule are described in part
XIII. This part also discusses the data
limitations and assumptions, and
determinations that the Agency made in
fulfilling its responsibilities under
Executive Order 12291.
Part XIV provides information on
where interested persons may obtain
copies of today's rule, the technical
support documents, the aggregate risk
assessment, and the regulatory impact
analysis. Included in this part is the list
of references cited throughout the
preamble.
Part XV describes the changes in 40
CFR parts 257 and 403. These changes
are limited to revisions to part 403 and
to removing from coverage in part 257
sewage sludge use and disposal
methods which will be subject to the
new standards the Agency is
establishing in 40 CFR part 503. Finally,
part XV lists the subjects in 40 CFR
parts 257, 403 and 503.
Part I: Generation, Use, and Disposal of
Sewage Sludge
Generation of Sewage Sludge
The CWA requires municipalities to
clean their wastewater prior to
discharging it. Wastewater treatment
generates sludge which in turn must
either be disposed of or used. Sludge
management begins with sludge
generation and continues through
sludge processing and ultimate disposal.
Domestic wastewater contains
material flushed into household drains
through toilets, sinks, and tubs.
Components of domestic sewage
include soaps, shampoos, human
excrement and tissue, food stuffs,
detergents, pesticides, household
hazardous waste, and oil and grease.
Typically a family of four discharges
300 to 400 gallons of wastewater per
day.
Domestic wastewater is treated (or
partially treated) at its source in septic
tanks, cesspools, portable toilets, or in
publicly or privately owned wastewater
treatment works. These treatment works
may treat domestic wastewater alone or
a combination of domestic wastewater
and industrial wastewater.
-------
9256 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Municipal wastewater treatment
works may use one or more levels of
treatment (i.e., primary, secondary, or
tertiary) to clean this wastewater. Each
level of treatment provides both greater
wastewater cleanup and greater
amounts of sewage sludge.
Primary treatment processes remove
the solids that settle out of the
wastewater by gravity. This generates
2,500 to 3,500 liters of sludge per
million liters of wastewater treated.
Primary sludge contains 3 to 7 percent
solids, 60 to 80 percent of which is
organic matter. The water content of
primary sludge can easily be reduced by
thickening or by removing water.
Secondary treatment produces a
sludge generated by biological treatment
processes. Biological treatment
processes (e.g., activated sludge
systems, trickling filters, and other
attached growth systems) utilize
microbes to break down and convert the
organic substances in the wastewater to
microbial residue. These processes
remove up to 90 percent of the organic
matter in the wastewater and produce a
sludge that typically contains from 0.5
to 2 percent solids. These solids are
generally more difficult to de-water than
primary sludges. The organic content of
thu solids ranges from 50 to 60 percent.
Secondary treatment processes increase
the volume of sludge generated over
primary treatment by 15,000 to 20,000
liters of sludge per million liters of
wastewater treated.
Advanced wastewater treatment
processes, such as chemical
precipitation and filtration, produce an
advanced or tertiary sludge. Chemical
precipitation uses chemicals to remove
organics and nutrients and to separate
the solids from the wastewater.
Characteristics of these sludges vary,
depending upon the type of advanced
treatment process used and the type of
wastewatcr entering the treatment
process. Since these sludges typically
contain considerable amounts of added
chemicals, the solids content will vary
from 0.2 to 1.5 percent, while the
organic content of the solids will be in
the 35 to 50 percent range. Tertiary
treatment increases the volume of
sludge generated over secondary
treatment by another 10,000 liters of
sludge per million liters of wastewater
treated.
Unprocessed sewage sludge contains
from 93 to 99.5 percent water, as well
as the solids and dissolved substances
that were present in the wastewater or
that were added or cultured by the
wastewater treatment process. While
virtually all sewage sludge contains
nutrients (e.g., nitrogen, phosphorus)
and significant numbers of pathogens
(e.g., bacteria, viruses, protozoa, and
eggs of parasitic worms), some sludges
also contain more than trace amounts of
organic chemicals (e.g., chloroform) and
inorganic chemicals (e.g., iron). These
pollutants come from domestic
wastewater, from the discharge of
industrial wastewater to municipal
sewers, and from the runoff from
parking lots and lawns and fields where
fertilizers and pesticides were
incorrectly applied.
Sludge Processing
Prior to reusing or disposing of
sewage sludge, treatment works
generally thicken, stabilize, and de-
water the sewage sludge. Sludge
thickening is the removal of water from
sludge to achieve a volume reduction.
The reduction in sludge volume
decreases the capital and operating costs
of subsequent sludge processing and
disposal operations. For example,
lowering the volume of sewage sludge
reduces transportation costs. EPA
estimates that the cost of transporting
sewage sludge with a 22 percent solids
content over a 20-mile trip is about one-
half the cost of transporting sewage
sludge with a 6 percent solids content
over the same distance.
Treatment works frequently digest or
compost their sewage sludge to reduce
the level of pathogens and odors. The
degree to which a sludge is processed is
very important when applying sewage
sludge to land, when distributing and
marketing it, and when placing sewage
sludge in monofills or on surface
disposal sites in order to eliminate the
spread of pathogenic diseases,
Amount of Sewage Sludge Generated
Approximately 12,750 POTWs
generate 5.4 million dry metric tons of
sludge annually (see Table 1-1), or 47
pounds of sewage sludge (dry weight
basis) for every individual in the United
States (based on Questionnaire Survey
and other sources).
Unless the volume of sludge is
reduced, the nation cannot achieve its
environmental quality objectives.
Treatment alone is not the answer.
Communities should consider the
following additional measures to reduce
the quantity of sludge generated by
wastewater treatment: implement waste
separation and water conservation
programs, encourage the recycling of
garbage in compost piles, separate
household hazardous waste prior to
collection and handling, and separate
storm water from wastewater sewer
systems. These measures have proved
successful in reducing the volume of
wastewater generated and in improving
the quality of the sewage sludge that is
ultimately used or disposed.
Use and Disposal Methods
Sewage sludge is commonly used or
disposed of in a number of ways. These
include the following: Application of
sludge to agricultural and non-
agricultural lands; sale or give-away of
sludge for use in home gardens (often
referred to as distribution and marketing
of sludge); disposal of sludge in
municipal landfills, sludge-only
landfills (known as monofills), and
surface disposal sites; and incineration
of sludge.
Table I—1 shows the amount of sludge
that is generated based on the size of a
facility and on the amount of sewage
sludge that is disposed of by a use or
disposal practice. Table 1-2 shows the
number of facilities using a particular
method of use or disposal.
TABLE 1-1.—ESTIMATED MASS OF SEWAGE SLUDGE DISPOSED ANNUALLY BY PRIMARY, SECONDARY, OR ADVANCED TREATMENT
POTWS BY SIZE OF POTW AND USE/DISPOSAL PRACTICE
[Thousands of dry metric tons]
Use or disposal practice
IncKViration ,
Land application:
Agricultural
Compost
Reported flow rate (MGD)
>100
382.9
203.0
22.4
>10tO 100
346.5
400.8
65.3
>1 to 10
124.8
423.9
31.7
£1
10.5
143.2
30.8
Total (per-
cent of total)
864.7
(16.1)
1,170.9
(21.9)
150.2
(2.8)
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9257
TABLE 1-1 .—ESTIMATED MASS OF SEWAGE SLUDGE DISPOSED ANNUALLY BY PRIMARY, SECONDARY, OR ADVANCED TREATMENT
POTWs BY SIZE OF POTW AND USE/DISPOSAL PRACTICE—Continued
[Thousands of dry metric tons]
Use or disposal practice
Sale
Undefined
Surface disposal:
Monofill
Other
Unknown:
Other
Transfer
Total
(Percent of total)
Reported flow rate (MGD)
>100
4.5
62.1
52.6
30.6
12.7
518.6
34.2
13.8
31.5
166.1
0
N/A
1,532.0
(28.6)
>10 to 100
24.5
60.5
9.8
27.8
76.4
674.0
124.9
79.8
60.0
157.9
0
N/A
2,128.3
(39.7)
>1 to 10
1.0
40.3
2.4
11.9
27.2
495.6
63.2
41.6
17.4
8.0
0
N/A
1,284.1
(24.1)
S1
1.3
6.3
1.0
0.8
13.0
110.4
36.5
22.2
28.5
3.4
0
N/A
407.7
(7.6)
Total (per-
cent of total)
32.3
(0.6)
166.1
(3.1)
65.8
(1.2)
71.1
(1.3)
129.3
(2.4)
1,818.7
(34.0)
258.8
(4.8)
157.4
(2.9)
137.5
(2.6)
335.5
(6.3)
0
N/A
5,357.2
(100.0)
Note: "This survey was conducted before the Ocean Dumping Ban Act of 1988, generally prohibited the dumping of sewage sludge into the ocean after December
31,1991. Ocean dumping of sewage sludge ended in June, 1992. Numbers may not add up to 100 percent because of rounding.
Source: Prepared by ERG for EPA—1988 National Sewage Sludge Survey and 1988 Needs Survey.
TABLE I-2.—NUMBER OF PRIMARY, SECONDARY, AND ADVANCED TREATMENT POTWs AND THE QUANTITY OF SEWAGE
SLUDGE DISPOSED ANNUALLY BY USE OR DISPOSAL PRACTICE
[Thousands of dry metric tons]
Use/disposal practice
Unknown:
Other
Transfer
All POTWs
POTWs using a use/disposal
practice
Number
381
4,657
2,991
1,351
133
3,920
25
13,458
Percent of
POTWs
2.8
34.6
22.2
10.0
1.0
29.1
0.2
100.0
Quantity of sewage sludge dis-
posed
Quantity
(1,000dmt)
864.7
1,785.3
1,818.7
553.7
335.5
0
N/A
5,357.2
Percent of
sludge
16.1
33.3
33.9
10.3
6.3
0.0
N/A
100.0
Note: The total number of POTWs does not equal the number in the text because some of the POTWs utilize more than one use or disposal practice and are
counted twice in this table.
•The National Sewage Sludge Survey was conducted before the Ocean Dumping Ban Act of 1988, generally prohibited the dumping of sewage sludge into the
ocean after December 31, 1991. Ocean dumping of sewage sludge ended in June, 1992. Numbers may not add up to 100 percent because of rounding.
Source: Prepared by ERG for EPA—1988 National Sewage Sludge Survey (Questionnaire Survey) and 1988 Needs Survey, and ERG estimates.
Benefits of Reusing Sewage Sludge
The organic and nutrient content of
sewage sludge (biosolids) makes it a
valuable resource to use both in
improving marginal lands and as a
supplement to fertilizers and soil
conditioners. A study of sewage sludge
and effluent use on selected agricultural
crops in one area of Oregon found that
the return per acre of sludge application
ranged from a loss of $6 to an increase
of $15 per acre. This was compared to
traditional fertilizer sources and
depended on crop rotation, previous
soil management practices, soil type,
and level of sludge application. The
farmer gained net savings in the cost of
fertilizers, taking into account the fact
that the sludge was available at no cost
(Reference No. 10).
The beneficial uses of sludge are not
limited to the production of agricultural
commodities. Sewage sludge is used in
silviculture to increase forest
productivity and to re-vegetate and
stabilize harvested forest land and forest
land devastated by fires, landslides, or
other natural disasters. The application
of sewage sludge to forest land shortens
wood production cycles by accelerating
tree growth, especially on marginally
productive soils. Studies at the
University of Washington on the use of
sludge as a fertilizer in silviculture
show height increases of up to 1,190
percent and diameter increases of up to
1,250 percent compared to controls in
certain tree species. University of
Washington research has also shown
-------
9258
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
that trees grow twice as fast on sludge-
amended soil. This means that a tree
which would typically be cut after 60
years could be cut after only 30 years to
supply lumber for a variety of purposes.
Sludge is productively used to
stabilize and re-vegetate areas destroyed
by mining, dredging, and construction
activities. Air-dried sludge that looks
Hke compost is frequently used to
fertilize highway median strips, clover-
loaf exchanges, and for covering expired
landfills. Historically, land reclamation
has been very successful and
comparable in cost to other commercial
methods. In a strip-mined area in Fulton
County, IL, reclamation using municipal
sewage sludge cost $3,660 an acre, as
compared with a range of $3,395 to
$5,290 an acre using commercial
methods (Reference No. 49).
Pennsylvania has used the sludge
Philadelphia generates to reclaim more
than 3,000 acres of devastated lands.
Sludge, in combination with fly ash, is
currently used in the re-vegetation of
soils that have become highly
contaminated from the operation of a
zinc smelter in Palmerton, PA, over the
past 90 years.
EPA analyses show that current
beneficial use practices (i.e., land
application, and sale and give-away)
pose less carcinogenic risk than disposal
practices. On a per ton basis,
carcinogenic risks from reusing sewage
sludge range from 8xlO""K to 4xlO~7,
while those from incinerating and
disposing of sewage sludge in monofills
range from 2xlo~^to 5xlO~6.
Studies using Philadelphia sludge
have shown that the microbial
communities in reclaimed mined soils
revert to those of normal soils within 2
to 3 years. Conventional reclamation
could take as long as 10 to 15 years, or
even longer (Reference No. 49).
Forest soils have been found to be
woll suited to sludge application
because they have high rates of
infiltration (which reduce run-off and
ponding), large amounts of organic
material (which immobilize metals from
the sludge), and perennial root systems
(which allow year-round application in
mild climates). Although forest soils are
frequently quite acidic, research at the
University of Washington has found no
problems with metal leaching following
sludge application (Reference No. 14).
In addition, studies of animals living on
sludge-treated sites have found that the
animals are healthier than those on
control sites because of the increased
production of vegetative matter.
The sale of sewage sludge products
can bo used to defray the costs of de-
watering and composting the sewage
sludge, But no similar mechanism exists
to defray the costs of de-watering
sewage sludge placed in landfills or
incinerated. Further, the labor, capital,
and operating and maintenance costs of
incinerating sewage sludge are
substantially higher.
The Municipality of Metropolitan
Seattle (METRO), which treats
wastewater in the Seattle-King County
region, began using sludge to improve
soil in several Seattle area parks, restore
land disturbed during strip mining,
restore a gravel pit used for Interstate 90
construction, and enhance grass growth
at the King County International Airport
at Boeing Field. In October 1983, the
METRO Council adopted a sludge
management plan that outlined a goal to
use at least eight alternative sludge
recycling or disposal methods through
the year 2000. METRO reports that its
plants produced 65,000 tons of sludge
in 1985 and more than 91,000 tons in
1987. Sludge production is expected to
increase dramatically in the next decade
after METRO'S Puget Sound plants are
upgraded from primary to secondary
treatment. METRO says that by creating
a demand for sludge and developing a
variety of recycling options, it reduced
program expenses from $227 per ton of
sludge solids in 1983 to $148 in 1987.
The benefits of using sewage sludge to
improve land productivity are
substantial. However, if sewage sludge
containing high levels of pathogenic
organisms (e.g., viruses, bacteria) or
high concentrations of pollutants is
improperly handled, the sludge could
contaminate the soil, water, crops,
livestock, fish, and shellfish. The major
human health, environmental, and
aesthetic factors of concern in the land
application of sewage sludge are related
to pathogens, metals and persistent
organic chemicals content, and odors.
The standards promulgated today would
prevent the contamination of soil and
crops by pathogens, as well as the
contamination of food and animal feed
crops when sewage sludge is applied to
lands used in the production of
agricultural crops or to lands that may
be converted to residential use.
While the use of sewage sludge for
beneficial purposes is primarily related
to farm and home garden use, use of
sewage sludge to aid in the growth of a
final vegetative cap for municipal solid
waste landfills is also considered a
beneficial use of sewage sludge and
should be encouraged. By taking
advantage of the nutrient content and
soil amendment characteristics of
sewage sludge, a vegetative cover or cap
can be quickly grown to facilitate the
municipal solid waste closure plan.
In spite of the benefits of reusing
sludge, only one-third of the sewage
sludge generated in the United States is
effectively reused by applying it to the
land, or sold or given away for use in
home gardens (see Table 1-2). In
comparison, Japan uses 42 percent of its
sewage sludge for coastal reclamation
and home garden or farming uses. The
United Kingdom applies 51 percent of
its sewage sludge to the land (Reference
No. 4).
While section 405 (e) of the CWA
reserves the choice of use and disposal
practices to local communities, EPA's
preference is for local communities to
reuse this resource in beneficial ways.
On June 12,1984, the EPA published its
policy on the management of sewage
sludge stating that the Agency will
actively promote those municipal
sludge management practices that
provide for the beneficial use of sludge
while maintaining or improving
environmental quality and protecting
public health (see 49 FR 24358).
When the quality of the sewage sludge
appears to be a limiting factor for an
otherwise desirable use, POTWs can
establish discharge limits for non-
domestic users discharging wastewater
to the POTW. Controlling the quality of
non-domestic wastewater discharged
into municipal sewers is an important
element in managing the quality of
sewage sludge.
All dischargers of non-domestic
wastewaters are required to meet all
applicable National Pretreatment
Standards. These may include general
and specific prohibited discharge
standards, categorical pretreatment
standards, and local limits.
In addition, POTWs designed to
accommodate design flows of more than
5 million gallons per day and smaller
POTWs with significant industrial
discharges are required to establish local
pretreatment programs. Currently 2,015
of the nation's POTWs operated by
1,528 authorities have local
pretreatment programs. The local
program must include adequate legal
authorities, industrial user permitting,
compliance monitoring, enforcement,
and public participation. These 1,528
approved programs are estimated to
receive 80 percent of the national
wastewater flow discharged to POTWs.
In addition to wastewater reduction
and the separation of contaminated
waste from uncontaminated wastes,
pretreatment of non-domestic
wastewater is another key step in
managing the quality of sewage sludge.
If pretreatment does not reduce the
pollutant levels sufficiently,
communities may have to dispose rather
than use their sludge and, depending on
the disposal method, add pollution
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9259
controls and thereby increase the cost of
sludge disposal,
Use of Sewage Sludge
Land Application to Agricultural Lands
Some 66 percent of the sludge applied
to land (approximately 1.2 million dry
metric tons) is used to improve the
condition and nutrient content of soil
for agricultural crops, including row
and feed crops and pastures. The
method of applying sludge to
agricultural land depends on the
physical characteristics of the sludge
and soil and on the crops grown. Liquid
sludge may be applied with tractors,
tank wagons, irrigation systems, or
special application vehicles. Liquid
sludge may also be injected under the
surface layer of the soil. Dewatered
sludge, on the other hand, is typically
applied to cropland by equipment
similar to that used for applying
limestone, animal manures, or
commercial chemical fertilizers.
Generally, the dewatered sludge is
applied to the land surface and then
incorporated by plowing or disking.
When applied to pasture land, sludge is
usually not incorporated into the soil.
Land Application to Non-Agricultural
Lands
Ten or more States have undertaken
sludge application to forest land, at least
on an experimental field-scale level.
The most extensive experience with this
practice is in the Pacific Northwest.
Sludge is most often sprayed from
mobile equipment into established
forest stands as a partially dewatered,
but still liquid, material. Other types of
non-agricultural land application
include sewage sludge applied to public
contact sites (e.g., parks, cemeteries, golf
courses) and reclamation sites.
When sewage sludge is used to
stabilize and re-vegetate land at
reclamation sites, typically large
amounts of sludge (up to 112 metric
tons per hectare or more) are applied on
a one-time basis. This large amount is
necessary to ensure that sufficient
organic matter and nutrients are
introduced into the soil to support
vegetation until a self-sustaining
ecosystem is established.
Land Application—Sale or Give-Away
of Sewage Sludge
Approximately 12 percent of the
sewage sludge generated is sold or given
away for use on home gardens. As a
method of managing sewage sludge, this
is a highly beneficial practice and one
the Agency encourages.
Usually, sewage sludge that is sold or
given away is composted, or heat dried
and formed into pellets. In composting
sewage sludge, the sludge is dewatered;
mixed with a bulking agent, such as
wood chips, bark, rice hulls, straw, or
previously composted sludge; and
allowed to decompose aerobically for a
period of time, hi this form, the sewage
sludge is dry, practically odorless, and
easier to distribute. It is also easier for
the user to handle. Sewage sludge that
is distributed and marketed is used as
a substitute for topsoil and peat on
lawns, golf courses, parks, and in
ornamental and vegetable gardens. Yield
improvements have been valued at $35
to $50 per dry ton over other potting
media.
Risks of Disposal Methods
Communities should consider
alternatives other than burying or
burning their sludge. These are wasteful
practices that pose risks and incur costs.
Some methods of sewage sludge
disposal, such as incineration and
uncovered landfills, may contribute to
global warming (i.e., the "greenhouse
effect") by releasing carbon dioxide and
methane.
Sewage sludge with high
concentrations of certain organic and
metal pollutants may pose human
health problems when disposed of in
sludge-only landfills (often referred to
as monofills) or simply left on the land
surface, if the pollutants leach from the
sludge into the ground water. Therefore,
the pollutant concentration may need to
be limited or other measures such as
impermeable liners must be taken to
ensure that ground water is not
contaminated.
For the incineration of sewage sludge,
municipalities must take sufficient
measures to control the emissions from
sewage sludge incinerators. Otherwise,
particulates, heavy metals, toxic organic
compounds, and hydrocarbons will add
to a community's air pollution
problems.
Ocean dumping of sludge, which
Congress banned after 1991, may result
in the destruction of biota that influence
the balance between oxygen and carbon
dioxide. In ocean disposal, certain
pollutants often associated with
municipal sludge, including mercury,
cadmium, and polychlorinated
biphenyls, can bioaccumulate. High
levels of these pollutants can interfere
with the reproductive systems of certain
marine organisms, may produce toxic
effects in aquatic life, or may present
public health problems if individuals
eat contaminated fish and shellfish.
Disposal Methods
Surface Disposal
Sewage sludge surface disposal—a
term used to describe what are
essentially piles of sludge left on the
land surface and includes land
application to dedicated non-
agricultural land and disposal in sludge-
only landfills—is a common means of
sludge disposal. The majority of surface
disposal sites are smaller than 1 acre
and receive less than 50 gallons per day
of waste.
Generally, surface disposal sites do
not have a vegetative or soil cover.
Depending on the State in which they
are located, surface disposal sites may
be regulated in a manner similar to
monofills or landfills. In other cases,
surface disposal sites are areas of land
where sewage sludge has been placed
for many years with little or no
consideration given to its ultimate
disposal.
Disposal on Dedicated Sites
Contained in the surface disposal
subpart of today's final rule is the
provision for applying sewage sludge at
greater than agronomic rates to grow
food, feed and fiber crops. These crops
may be grown and animals grazed if the
owner/operator demonstrates to the
permitting authority, that through
management practices, public health
and the environment are protected from
reasonably anticipated adverse effects of
pollutants in sludge.
Municipal sewage sludge is often
applied at greater than agronomic rates
at sites specifically set aside for
municipal sludge management. Such
application rates are needed to reclaim
and restore marginal and disturbed
soils, such as strip mines, to full
agricultural productivity. Sludge
contains organic matter typically in the
range of 30 to 50 percent. Barren and
strip-mine soils contain organic matter
levels of less than one-half percent
which is considerably less than the
three to five percent needed for full
agricultural productivity. In addition,
such sites may likely be barren, very
erodible and acidic, and a threat to
ground and surface waters. Sludge
applications greater than agronomic
rates and even cumulative rate limits
can overcome the barren, erosion and
acid problems. Moreover, these
applications can restore the organic
matter levels to that needed to produce
such commercial agricultural crops such
as corn which would have been
impossible to produce otherwise.
Sites which use sludge application at
greater than agronomic rates are
generally owned, operated, and
-------
9260 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
controlled by, or are controlled under
long-term leases to, the municipal
sludge operator. Generally, public
access to these sites is strictly
controlled. Sites may range in size from
ten acres to greater than 10,000 acres.
Sludges applied to such dedicated
beneficial use sites apply nitrogen,
phosphorus, and other macro- and
micro-nutrients to crops and as was
already stated may also be used to
condition soils at sites containing
disturbed lands. For example, the
Metropolitan Water Reclamation District
of Greater Chicago has been operating a
15,600 acre site for 20 years in Fulton
County, Illinois. Sewage sludge is
applied to condition and fertilize strip-
mine spoils to produce crops, such as
corn, which are sold as animal feed or
for alternative fuel production, and is
also used to reclaim acid coal refuse
piles with vegetative cover.
In contrast to their large, rural, Fulton
County site, the Metropolitan Water
Reclamation District of Greater Chicago
also operates a site in the Village of
Hanover Park, one of Chicago's
residential suburbs. The site lies on the
property of the District's Hanover Park
Water Reclamation Plant and the entire
annual sludge production is utilized to
fertilize row crops and nursery stock.
This 120 acre farm, complete with a tile
drainage system for recirculation of field
percolate, has been successfully
operated for 13 years and has
harmoniously coexisted with its "across
the fence" neighbors, a grade school and
a community of single family homes.
However, the primary objective of this
practice is to employ the land as a
treatment system by using soil to bind
metals and by using soil
microorganisms, sunlight, and oxidation
to destroy the organic matter and
pathogens in the sludge. These sites are
generally owned by, or are under long-
tunn leases to, a treatment work.
Frequently, the dedicated land disposal
site has a non-food chain vegetative
cover crop (e.g., sod, pulpwood) to
reduce the potential for runoff or
leaching of the pollutants to surface or
ground water. In some cases, as
discussed above, an attempt is made to
use the nutrient and soil conditioning
properties of the sewage sludge to grow
crops for methanol production or for
other purpose.
Landfilling
Landfilling is a sludge disposal
method in which sludge is deposited in
a dedicated area, alone or with solid
waste, and buried beneath a soil cover.
Landfilling is another disposal method
that does not attempt to recover the
nutrient content of the sludge for
beneficial uses. However, the
decomposition of organic matter in
sewage sludge that is landfilled
produces methane gas. The methane gas
can be recovered and yields an energy
value more than half as great as that of
natural gas.
Thirty-three percent of the sewage
sludge disposed of by 22 percent of the
POTWs is landfilled with municipal
solid waste. In co-disposal, the
absorption characteristics of the solid
waste and soil conditioning
characteristics of the sludge
complement each other. The solid waste
absorbs excess moisture from sludge
and reduces leachate migration. Sewage
sludge usually makes up 5 percent or
less of the material in a solid waste
landfill.
Slightly less than 3 percent of the
sewage sludge generated is disposed of
in monofills (landfills only accepting
sewage sludge). EPA has identified
approximately 320 POTWs that dispose
of their sewage sludge in monofills.
Most monofills consist of a series of
trenches, dug into the ground, into
which dewatered sludge is deposited
and then covered with soil. Other
monofill designs, in which the sludge is
deposited on the ground surface (area
fill mounds, area fill layers, and diked
containment), do exist but are not
commonly used.
Incineration
Incineration is a method of disposal
that destroys the organic pollutants and
reduces the volume of sewage sludge.
Incineration takes place in a closed
device using a controlled flame. EPA
estimates that approximately 0.9 million
dry metric tons of sewage sludge are
incinerated each year, accounting for
more than 16 percent of the sewage
sludge disposed of by POTWs.
If the sewage sludge contains 20
percent solids, incinerators reduce the
volume of sewage sludge by about 90
percent, on a wet weight basis. While
this reduces the amount of material that
must be landfilled, owners or operators
must control the concentration of the
pollutants in the incinerator emissions
to prevent exacerbation of a
community's air pollution control
problems. They must also allocate
sufficient funds to pay for the labor,
capital, operating, and maintenance
costs of sewage sludge incinerators.
Approximately 110 (52 percent) of the
sewage sludge incinerators operated by
secondary and advanced treatment
works in the United States were built
prior to 1973, when the New Source
Performance Standards for Sewage
Sludge Incinerators were published (40
CFR part 60, subpart O). Multiple hearth
incinerators are the most commonly
used sewage sludge incinerators with
156 multiple hearth incinerators (74
percent firing sewage sludge). Other
types include 49 fluidized bed
incinerators (23 percent of the total), 3
flash drying incinerators, and 2 electric
furnaces. A description of these
incinerators is included in the
Technical Support Document for
Incineration (Reference No. 100).
The total estimated volume of sewage
sludge fired in incinerators operated by
POTWs in 1988 was approximately
860,000 dry metric tons. Not
represented in this estimate are
incinerators which fire sewage sludge
with solid waste in municipal waste
combustors. The Agency estimates that
seven facilities practice co-incineration
of sewage sludge with municipal solid
waste.
Part II: Federal and State Requirements
The use or disposal of sewage sludge
is currently subject to some Federal
regulation. Existing Federal regulations
are authorized under several statutes
and have been developed independently
along media-specific concerns. State
regulations generally are keyed to
Federal regulatory requirements,
primarily those in 40 CFR part 257,
covering the land application and
landfilling of sewage sludge, and those
in 40 CFR part 60, subpart O, covering
sewage sludge incinerators.
This part starts with a discussion of
the requirements of the CWA, followed
by a description and summary of other
Federal and State regulatory
requirements and how they relate to
today's rule.
Clean Water Act Statutory
Requirements
Sewage sludge has been an important
concern of the Agency since 1972, when
EPA, through the Federal Water
Pollution Control Act construction
grants program, began assisting in the
financing of wastewater treatment
facilities. The Clean Water Act of 1977
amended section 405, mandating that
EPA develop guidelines for the use and
disposal of sewage sludge. As
previously explained, under section
405(d), EPA was required to issue
regulations that:
(1) Identify uses for sewage sludge,
including disposal;
(2) Specify factors to be taken into
account in determining the measures
and practices applicable to each such
use or disposal (including publication of
information on costs); and
(3) Identify concentrations of
pollutants which interfere with each
such use or disposal.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9261
Responding to this mandate, in 1979,
EPA adopted criteria that provided
guidelines for sewage sludge use and
disposal when sewage sludge was
applied to land or disposed of in
landfills. These criteria were included
in regulations co-promulgated under
Subtitle D of RCRA and section 405(d)
of the CWA and are found in 40 CFR
part 257. These regulations contain a
number of specific requirements for the
management of sewage sludge. To
protect the ground water, the
regulations prohibit any use or disposal
of sewage sludge that causes the
concentration of 10 heavy metals and 6
organic chemicals in an underground
drinking water source to exceed
maximum contaminant levels (MCLs)
specified in the criteria. The criteria also
included management standards
applicable to sewage sludge use or
disposal methods to protect surface
waters, flood plains, and endangered
species. The criteria contain limitations
on the concentration of two pollutants
(cadmium and PCBs) in sewage sludge
when the sewage sludge is applied to
the surface of land used for the
production of animal feed or food-chain
crops. In addition, the requirements in
part 257 restrict sewage sludge use and
disposal except in compliance with
certain measures to control pathogens
and disease-carrying rodents, insects,
and birds. The regulation provided for
different levels of pathogen reduction,
depending on whether crops for direct
human consumption were grown or
animals for human consumption were
allowed to graze on the sewage sludge-
amended soil. The processes for
reducing the levels of pathogens include
aerobic and anaerobic digestion,
composting, lime stabilization, and heat
treatment and drying.
As part of its sludge regulatory
program, EPA has prepared a number of
documents which provide guidance and
direction to local POTWs on the proper
management and handling of sewage
sludge. EPA has actively encouraged
and assisted in the development and
implementation of various practices and
processes leading to the beneficial use
of sewage sludge. In addition to
supporting long-term research and
demonstration projects, the Agency has
also assisted in the development of
detailed design guidance for various
beneficial methods of disposal and such
technologies as digestion, composting,
and lime stabilization. The Agency has
also supported development of
improved de-watering systems,
pyrolysis, and other technologies to
improve energy recovery from thermal
conversion systems, methane recovery
from anaerobic digestion systems, and
the recovery of various potentially
marketable by-products from sewage
sludge.
To aid in developing the
comprehensive sewage sludge
regulations promised in the preamble to
the 40 CFR part 257 rule (44 FR 53439,
September 13,1979), EPA created an
Intra-Agency Sludge Task Force in 1982.
The task force was assigned the
following tasks: (1) Conduct a
multimedia examination of sewage
sludge management, focusing on sewage
sludge generated by POTWs; and (2)
develop a cohesive Agency policy on
sewage sludge management, designed to
guide the Agency in implementing
sewage sludge regulatory and
management programs. Numerous
Agency offices and ad hoc groups had
wrestled with sewage sludge
management, but none of these groups
had been able to decide how to
equitably regulate nationally a complex
and variable waste in an
environmentally protective and cost-
effective manner. Sewage sludge use or
disposal involved a myriad of site-
specific circumstances, could result in
multimedia effects, and depended on
proper planning and decision-making at
the local level. The Agency lacked
experience in developing performance
standards for solid waste that would
attenuate multimedia environmental
effects. Furthermore, at that time,
Congress had not provided a
compliance mechanism for the
regulations.
The task force, which included
representatives from all parts of the
Agency, recommended that the Agency
develop an integrated, comprehensive
regulatory structure for sewage sludge
use or disposal using the combined
authorities of section 405 of the CWA
and other laws. This structure would
also incorporate existing regulations
and, where appropriate, new regulations
to complete regulatory coverage where
important gaps remained.
While the Agency was working on a
regulatory approach consistent with the
recommendations of the Task Force, the
Natural Resources Defense Council sued
the Agency over EPA's pretreatment
regulation (40 CFR part 403). In that
suit, the U.S. Court of Appeals for the
Third Circuit ruled that the
pretreatment regulation was invalid in
four respects. [Natural Resources
Defense Council v. EPA, 790 F.2d 289
(3rd Cir. 1986)]. Most relevant here is
the court's fourth holding:
We hold that, despite EPA's contention
that sludge regulations are in place, EPA's
device of incorporating other regulations
does not meet the statute's command for a
comprehensive framework to regulate the
disposal and utilization of sludge and that
EPA cannot, in the absence of section 405(d)
regulations authorize the issuance of removal
credits under section 307(b)(l).
Throughout its lengthy consideration
of the amendments to the CWA, some
members of Congress expressed concern
that, without sewage sludge regulations,
industry would continue to discharge
toxic pollutants into wastewater for
POTWs to treat, making it more difficult
for a city to find sewage sludge
management alternatives. They believed
sludge criteria would stimulate effective
pretreatment programs and would
encourage recycling and reuse of toxic
pollutants by industry. In the Water
Quality Act of 1987 (Pub. L. 100-4,
February 4,1987), Congress reaffirmed
its directive that EPA develop
comprehensive sewage sludge
regulations and set forth a schedule for
the Agency to do so. The Water Quality
Act amended section 405(d) to include
requirements that:
(1) By November 30,1986, EPA propose
regulations establishing numerical limits and
acceptable management practices for toxic
pollutants that EPA identified as present in
sewage sludge in concentrations which, on
the basis of information available on their
toxicity, persistence, concentration, mobility,
or potential for exposure, may adversely
affect public health or the environment;
(2) By August 31,1987, EPA promulgate
regulations specifying acceptable
management practices and establishing
numerical limits for these pollutants that
"shall be adequate to protect public health
and the environment from any reasonable
anticipated adverse effects of each
pollutant";
(3) By July 31,1987, EPA identify and
propose regulations for those toxic pollutants
not identified in the regulations promulgated
August 31,1987, and promulgate regulations
for those toxic pollutants by June 15,1988;
and
(4) From time to time, but no less often
than every two years, EPA review the
regulations for the purpose of identifying
additional toxic pollutants and promulgating
regulations.
The amendments specify that
compliance with the regulations'
requirements must occur not later than
1 year after publication of the
regulations, unless the regulations
require the construction of new
pollution control facilities. In this latter
case, compliance must occur no later
than 2 years from the date of publication
of the regulations.
Section 405(d)(5) also provides that
nothing in the section is intended to
waive more stringent requirements in
the CWA or in any other law. This
means that States and local
communities remain free to impose
more stringent requirements than those
-------
9262 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
included in today's rule. In addition, as
described later in the preamble, where
EPA has established requirements
applicable to sewage sludge under other
statutes, compliance with regulations
established under those statutes also
constitutes compliance with part 503.
Section 405(ej was further amended
to read as follows:
Tlio determination of the manner of
disposal for USD of sludgo is a local
determination, except that it shall be
unlawful for any person to dispose of sludge
from a publicly owned treatment works or
any other treatment works treating domestic
sowago for any use for which regulations
have boon established pursuant to subsection
(d) of this section, except in accordance with
such regulations.
The implications of this section are
discussed later in the preamble.
CERCLA Liability
Questions have been raised about
conditions under which sewage sludge
disposed at a Suporfund site might give
riso to liability under the
Comprehensive Environmental
Response, Compensation and Liability
Act (CERCLA).
Section 107 of CERCLA generally
imposes liability for cleanup costs on,
among others, persons who own or
operate facilities at which hazardous
substances are disposed. Section 107
liability extends to the costs of cleanup
necessitated by a release or threat of
release of a hazardous substance.
However, section 101(22) defines
"release" to exclude the "normal
application of fertilizer."
If the placement of sludge on land
were considered to be "the normal
application of fertilizer," that placement
could not give rise to liability under
CERCLA. Today's rule, as previously
noted, establishes standards for sewage
sludge when applied to the land for a
bunuficial purpose (i.e., as a fertilizer
substitute or soil conditioner). Sludge
placed on the land for such beneficial
purpose and applied in compliance
with the requirements for land
application of sewage sludge provided
in §§503.13(b) (2) and (4), §503.14 and
§503.15 (where applicable) of the final
rule today, and in accordance with
accepted agricultural practices using
appropriate application rates, which
constitutes the normal application of
fertilizer, does not constitute a
"release."
Under CERCLA, protection from
liability is also provided when there is
a release of a CERCLA hazardous
substance and the release occurs
pursuant to Federal authorization. Thus
under CERCLA, in defined
circumstances, the application of
sewage sludge to land in compliance
with a permit required by section 405 of
the Clean Water Act is a Federally
permitted release as defined in
CERCLA. Recovery for response costs or
damages under section 107 of CERCLA
is not authorized for Federally
permitted releases. The Act defines
Federally permitted releases as, among
others, discharges in compliance with
an NPDES permit under section 402 of
the Clean Water Act. (See, Idaho v.
Hanna Mining Co. 699 F. Supp. 827 (D.
Idaho 1987) (State cannot recover under
CERCLA for damages resulting from
releases authorized by NPDES permit)
affd, 882 F.2d 392 (9th Cir. 1989)).
Consequently, releases of hazardous
substances from the land application of
sewage sludge authorized under and in
compliance with an NPDES permit
would constitute a Federally permitted
release.
Other Federal Requirements
Traditionally, the Agency has used
the standards, definitions, and
approaches developed under other
Federal public health and
environmental programs in responding
to the broad mandate of section 405(d)
when they are consistent with the goals
and objectives of the CWA. The use of
other Federal standards is desirable in
order to minimize duplicative,
overlapping, and conflicting policies
and programs. Further, as discussed
above, section 405 (d) (5) provides that
nothing in section 405(d) is intended to
waive more stringent requirements
established under other statutes.
Therefore, as previously indicated, in
developing today's rule EPA based
pollutant limits on human health or
environmental criteria established
under other statutory authorities.
Under section 304(a) of the CWA, the
Agency publishes Water Quality
Criteria. For the purposes of part 503,
these criteria are used in determining
whether a pollutant limit for a particular
use or disposal practice would not
exceed a freshwater quality criterion,
should the pollutant reach the surface
water. When the concern is to protect
the drinking water supplies, the basis of
the pollutant limits is the MCLs
promulgated under authority of the Safe
Drinking Water Act.
The NAAQS for lead, promulgated
under authority of section 109 of the
Clean Air Act, was used in developing
the pollutant limit for lead when sewage
sludge is incinerated. The National
Emission Standards for Hazardous Air
Pollutants (NESHAPs) for beryllium and
mercury, used in the part 503 proposal
to develop the numerical pollutant
limits for these pollutants when sewage
sludge is incinerated, have been omitted
from the final part 503 regulations
because these pollutants are already
regulated under the authority of section
112 of the Clean Air Act and found at
40 CFR part 61. Other applicable
regulatory requirements for the
incineration of sewage sludge include
the New Source Performance Standards
for Sewage Sludge Incinerators
promulgated under section 111 of the
Clean Air Act and found at 40 CFR part
60, subpart O. Owners or operators of
sewage sludge incinerators also must
ensure that their operations, including
the location of new incinerators,
conform to state implementation plans
approved under the regulations
authorized by section 110 of the Clean
Air Act and are found at 40 CFR parts
50-51.
State Requirements
The information on existing State
requirements summarized below was
gathered as part of EPA's effort in
developing guidance for writing sewage
sludge interim permits prior to
promulgation of the part 503 standards.
Under section 510 of the CWA, States,
political subdivisions of States and
interstate agencies retain the authority
to adopt or enforce more stringent
standards than those provided in
today's part 503 regulations.
At present, 42 States have regulations
or guidelines covering the land
application of sewage sludge which set
either a maximum allowable
concentration or maximum pollutant
loading rate for at least one pollutant.
Paralleling the requirements in 40 CFR
part 257, 41 States have set restrictions
on the growing of crops on soil to which
sludge has been applied (e.g., human
food chain crops cannot be grown on
sludge-amended soil until 18 months
after the application of the sewage
sludge). In addition, 41 States have
established management practices for
the land application of sewage sludge.
The give-away or sale of composted
sludge is regulated under State land
application requirements. Eleven States
have set numerical limits on the
concentration of pollutants in sewage
sludge that is distributed and marketed
and 22 States have established
management practices regulating this
use.
Many States enforce landfilling
restrictions for nonhazardous sludge
that follow the requirements in 40 CFR
part 257. While States have not set
maximum pollutant concentrations for
sewage sludge that is landfilled, 31
States do have some site restrictions or
other management practices governing
landfills.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9263
Many States regulate the emissions of
sewage sludge incinerators. State
implementation plans under the Clean
Air Act limit emissions of various
pollutants subject to NAAQS or
NESHAPs. Twenty States have
established opacity limits as well as
emission limits for beryllium, mercury,
particulates, sulfur dioxide, and carbon
monoxide. No State has established a
limitation on lead emissions from
sewage sludge incinerators. Twenty-
nine States have regulations or
guidelines governing operation of
incinerators, including disposal of ash.
In one State, the development and
enforcement of controls on all methods
of sewage sludge use and disposal are
delegated entirely to local agencies, as is
the issuance of permits. In other States,
local as well as State controls are
imposed on the use and disposal of
sewage sludge.
Part III: Selection of Pollutants
Considered for Regulation
This part describes how the Agency
selected the initial list of pollutants for
which numerical limits are promulgated
in today's rule and data bases used to
collect information about the pollutants.
Additional information may be found in
"The Record of Proceedings on the
OWRS Municipal Sewage Sludge
Committees" and "Summary of the
Environmental Profiles" (Reference Nos.
62 and 67).
Initial List of Pollutants
In the spring of 1984, EPA enlisted
the assistance of Federal, State,
academic, and private sector experts to
determine which pollutants likely to be
found in sewage sludge should be
examined closely as possible candidates
for numerical limits. These experts
screened a list of approximately 200
pollutants in sewage sludge that, if
disposed of improperly, could cause
adverse human health or environmental
effects. The experts were requested to
revise the list, adding or deleting
pollutants. The test for inclusion or
exclusion was the potential risk to
human health and the environment
when sewage sludge containing a
particular pollutant was applied to the
land, placed in a landfill, or incinerated.
The Agency also requested that the
experts identify the most likely route
which a pollutant could travel to reach
target organisms, whether human, plant,
or wild or domestic animals. The
experts attending the meetings
recommended that the Agency gather
additional environmental information
on approximately 50 pollutants. These
pollutants are listed in Table III-l.
TABLE 111-1 .—POLLUTANTS SELECTED FOR ENVIRONMENTAL PROFILES/HAZARDS INDICES
Pollutants
Aldrin/Dieldrin
Benzene
Benzidine . . . ..
Benzo(a)anthracen6
Benzo(a)pyrene . ..
Beryllium
Bis(2-ethylhexyl) phthalate
Cadmium
Carbon tetrachloride
Chlordane
Chlorinated dibenzodioxins
Chloroform
Chromium
Cobalt
Copper
Cyanide
DDT/DDD/DDE
3 S'-Dichlorobenzidine
2,4-Dichlorophenoxy-acetic acid
Dimethylnitrosamine
Heptachlor
Hexachlorobenzene .
Hexachlorobutadiene
Iron
Lead
Lindane
Malathion
Mercury
Methylene bis(2-chloroaniline)
Methylene chloride
Methylethyl ketone
Molybdenum
Nickel
PCBs
Pentachlorophenol
Phenanthrene
Phenol
Selenium
Tetrachloroethylene
Toxaphene
Trichloroethylene
Trichlorophenol . .
Tricresyl phosphate
Vinyl chloride
Zinc
Land application
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
Landfill
X
X
X
X
x
X
X
x
X
X
x
X
X
X
x
X
x
x
X
X
X
X
x
X
Incineration
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
-------
9264 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Environmental Profiles
During 1984 and 1985, the Agency
collected data and information from
published scientific reports on the
toxicity, persistence, means of transport,
and environmental fate of these 50
pollutants. EPA also developed
preliminary information on their
relative frequency of concentration in
sewage sludge by analyzing the sewage
sludge of 43 to 45 POTWs (depending
on the pollutant) in 40 cities ("Fate of
Priority Pollutants in Publicly Owned
Treatment Works"—the "40 City
Study"—Reference No. 60). The sewage
sludge data from the "40 City Study"
consist of concentrations of 40
pollutants (12 metals, 6 base neutral
organic compounds, 6 volatile organic
compounds, 9 pesticides, and 7 PCBs)
in sewage sludge analyzed from the
target POTWs.
Using this preliminary information on
the relative frequency and concentration
of pollutants in sewage sludge, their
toxicity and persistence, the pathways
by which the pollutants travel through
the environment to a receptor organism
(plant, animal, or human), the
mechanisms that transport or bind the
pollutants in the pathway, and the
effects of the pollutants on the target
organism, EPA made an assessment of
the likelihood that each pollutant would
adversely affect human health or the
environment. For this analysis, EPA
relied on simple screening models and
calculations to predict the concentration
of a pollutant that would occur in
surface or ground water, soil, air, or
food. EPA then compared the predicted
concentration with an Agency human
health criterion, such as a drinking
water standard promulgated under the
Safe Drinking Water Act, to determine
whether the pollutant could be expected
to have an adverse effect on human
health. For purposes of this initial
screening, EPA assumed conditions that
would maximize the pollutant exposure
of an individual, animal, or a plant, as
well as the worst possible pollutant-
related effects.
Based on the factors previously listed
(concentration, toxicity, persistence,
and others), EPA scored each pollutant
and ranked them for more rigorous
analysis. EPA excluded two categories
of pollutants for further evaluation.
First, EPA excluded pollutants which,
when compared to a simple index,
presented no risk to human health or
the environment at the highest
concentration that the Agency found in
the "40 City Study" or in other available
data bases. Second, EPA deferred
consideration of pollutants for which
EPA lacked human health criteria or
sufficient data.
Information on each pollutant, the
simple screening models and
calculations used to describe the
pollutant's path through the
environment, and the indices used to
evaluate the pollutant are compiled in
an environmental profile for each
pollutant. The summary of the
environmental profiles is listed as
Reference No. 64 in part XIV of the
preamble.
Table III-2 shows the pollutants EPA
did not analyze further because the
pollutant did not exceed an EPA human
health or environmental criterion at the
highest concentrations shown in the "40
City Study." The pollutants listed in
Table III-2 are also included in the list
of pollutants for which eligible POTWs,
complying with the requirements in part
503, may under 40 CFR part 403, apply
for authorization to grant removal
credits to their industrial dischargers
(see Part XV—Description of the
Amendments to 40 CFR Parts 257 and
403).
Table III-3 shows the pollutants for
which a lack of data at the time of
developing these regulations precluded
the Agency from promulgating
numerical limits at this time.1 Included
on the list in Table III-3 is dioxin. When
EPA initiated these pollutant
assessments in 1984, the Agency did not
include dioxin as a pollutant evaluated
for this rule. At that time, EPA lacked
the data required to assess numerical
limitations for dioxin in sewage sludge.
In addition, adequate data were not
available on the levels of dioxin or its
pervasiveness in sewage sludge.
TABLE 111-2.—POLLUTANTS EVALUATED AND FOUND NOT To INTERFERE WITH SEWAGE SLUDGE USE OR DISPOSAL
Pollutants
ChftHdano
Chromium
Cyankla'
Dimethyl ntlrosambio*
2,4-DicMoiophonoxy.acGtk: acid
Fkxxida"
Hoptochior
Iron* ....,„
Malalhton
Molybdenum
Nisfcol
PontacWojophonol
Phono)
Selenium
Tolrachlorooihytono*
Zinc- „
Use/disposal practice (concentration)
(2,686.6 mg/kg).
Distribution and Marketing (2 55 mg/kg)
Monofill (716 mg/kg)
Monofiil (0 63 mg/kg)
Monofill (40 mg/kg)
Monofill (82 06 mg/kg)
Monofill, Incineration (4,580 mg/kg)
•Exposure assessment models were used In determining that these pollutants, at the concentrations shown, do not interfere with the use or disposal of sewage
slodgo.
1 Somo of Iho organic pollutants for which
dovelojimonl of regulatory limits wore deferred are,
In fact, regulated in this rule. As explained.
Incinerator organic pollutant omissions are limited
by nil operational standard for total hydrocarbons.
Thus, because the emissions of total hydrocarbons
are regulated, emissions of the following Table III-
3 pollutants are, in actuality, regulated in the final
rule: benzo(a)anthracene, phenanthrene and vinyl
chloride.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9265
TABLE 111-3.— POLLUTANTS DEFERRED
BECAUSE OF INSUFFICIENT DATA
Pollutants
Benzo(a) anthracene
Bis(2-ethylhexyl)
phthalate.
Chlorinated dibenzo-
dioxins.
Chlorinated dibenzo-
furans.
Cobalt
Methylene bis (2-
chloroanline).
Methylene chloride
Methylethyl ketone
Pentachlorophenol
Phenanthrene
Tricresyl phosphate
Vinyl chloride
Use/Disposal Practice
Land Application, Distribution
and Marketing, Inciner-
ation.
Distribution and Marketing.
Land Application, Distribution
and Marketing, Monofills.
Land Application, Distribution
and Marketing, Monofills.
Land Application, Distribution
and Marketing, Monofills.
Land Application, Distribution
and Marketing.
Land Application, Distribution
and Marketing, Monofills.
Monofills.
Land Application, Distribution
and Marketing.
Monofills, Incineration.
Land Application, Distribution
and Marketing.
Incineration.
The Agency did not analyze sewage
sludge for dioxins as part of the "40 City
Study" because, at the time the samples
were collected (1979-1980),
methodologies did not exist for
analyzing trace quantities (parts per
trillion) of dioxins in sewage sludge.
Since better analytical methods no.w
exist, the Agency has collected sewage
sludge samples for dioxins analyses as
part of the National Sewage Sludge
Survey (NSSS) (see discussion below).
EPA will use the NSSS data and the
results of recent scientific studies to
complete its analysis of dioxins in
sewage sludge—a likely candidate for
regulation in the second round of
sewage sludge regulation. In the interim,
as explained later in the preamble, the
Agency is limiting the emission of
dioxins from sewage sludge incinerators
by establishing operating standards for
total hydrocarbons.
Part IV: February 6,1989 Proposed
Rule
This part describes the sewage sludge
use and disposal standards EPA
proposed in February, 1989. In that
notice, EPA proposed to include septage
from septic tanks in the definition of
sewage sludge and thus within the
scope of the proposed requirements. A
more detailed explanation of the
proposed rule is found at 54 FR 5746,
5791-5855 (February 6,1989).
The proposed standards included
numerical pollutant limits, management
practices, and other requirements that
defined a level of control which owners
or operators of treatment works and
users or disposers of sewage sludge
must attain over the use or disposal of
sewage sludge in order to protect human
health and the environment. EPA
proposed pollutant limits, management
practices, and other requirements that
were specific to the method of use or
disposal employed by treatment works
use.
EPA proposed requirements that
owners or operators of treatment works
and users or disposers of sewage sludge
would have to meet whenever they
ultimately used or disposed of the
sludge. The use or disposal methods
included in the proposal were: (1)
application to agricultural or non-
agricultural land, (2) distribution and
marketing (now referred to as sale or
give-away of sewage sludge), (3)
disposal in monofills, (4) disposal on
surface disposal sites, and (5)
incineration. EPA did not propose
separate standards for septage from
septic tanks. Rather, septage, when used
or disposed of by any method regulated
under the proposal (e.g., applied to
land, placed in a monofill or surface
disposal site) would have to meet the
applicable requirements in the same
manner as those for sewage sludge.
Land Application
EPA proposed standards for the
spreading of liquid, de-watered, dried,
or composted sewage sludge on or just
below the surface of agricultural and
non-agricultural land. Sewage sludge
applied to agricultural land was subject
to different numerical pollutant limits
from those limits proposed for sludge
applied to non-agricultural lands.
EPA based the numerical limits for
sewage sludge when applied to
agricultural land on a modelled
assessment of potential risk to public
health and the environment through 14
pathways of exposure. The numerical
limits for sewage sludge when applied
to agricultural land were expressed in
terms of a limitation on the cumulative
loading of 10 metals and an annual
pollutant loading of 12 organic
pollutants. The cumulative loading rate
for each of the metals represented the
limit on how much of a given metal in
sludge could be added to the soil. The
additional "load" of the metal could be
applied all at once or over a period of
years from repeated applications of
sludge. No further application of sludge
containing the metal would be allowed,
however, once the cumulative loading is
reached. In addition, the proposed rule
also limited, on an annual basis, the
quantity of 12 organic pollutants that
could be applied to land. In order to
ensure that the cumulative loading level
and annual pollutant rates would not be
exceeded, the proposal required owners
and operators of treatment works to
keep records on the amount of organic
and inorganic pollutants applied to each
land application site. In addition, before
sewage sludge could be applied to the
land by any one other than the
treatment works, under the proposal the
treatment works would have to enter
into an agreement with the distributor
or applier of the sludge to provide that
they must comply with the standards.
In the case or non-agricultural land,
EPA developed pollutant ceilings for the
concentration in sewage sludge of these
22 organic and inorganic pollutants. The
standards were premised on the
assumption that pollutants in sludge
applied to non-agricultural land would
not reach individuals through the food
chain. The ceiling concentrations were
based on 98th-percentile values for
pollutant concentrations in municipal
sewage sludge based on data from a
1981-82 study.
Distribution and Marketing
Different requirements were proposed
for sewage sludge which is distributed
and marketed—what is now
denominated sludge that is sold or given
away—for use as a fertilizer and soil
conditioner for potting medium, lawns,
ornamental plants and gardens. In the
case of distributed and marketed sludge,
the Agency proposed to limit the
quantity of sludge (or a product derived
from the sludge) of a given
concentration that could be applied to
land in one year. When a treatment
works was not the distributor of the
sludge or sludge product, the proposal
required an agreement between the
distributor and treatment works to
ensure compliance with the
requirements.
An important difference between the
proposed land application requirements
and the proposed distribution and
marketing requirements was in the
numerical limits for some of the organic
pollutants and some metals. In the
exposure assessment pathway scenarios
for both, it was assumed that the sewage
sludge is used in the production of
crops intended for human consumption.
The numerical limits for the application
of sewage sludge to agricultural land
were based on crops intended for direct
human consumption or fed to animals
intended for direct human
consumption, whichever was the more
stringent loading rate. For the organic
pollutants, which tend to bioaccumulate
through the food chain, the limiting
numerical limit was based on crops fed
to animals intended for human
consumption. However, the distribution
and marketing scenario was designed to
protect a fruit and vegetable home
garden, not a garden in which feed is
raised for animals intended for human
consumption. Therefore, the numerical
limits for organic pollutants in
-------
9266 Federal Register / Vol. 58, No. 32 /Friday, February 19, 1993 / Rules and Regulations
distribution and marketing tended to be
higher than those for agricultural land
application.
Another major difference in the
proposed requirements between the
land application standards and the
distribution and marketing standards
was that for the land application
requirements to apply, as noted, there
had to be an agreement between the
treatment works and the distributor or
applior of the sewage sludge to abide by
the requirements, such as the access and
use restrictions. In the absence of an
agreement, the proposal required the
treatment works to comply with the
requirements for the distribution and
marketing standards.
Monofills
EPA also proposed requirements that
would apply to landfills receiving only
sewage sludge (monofills) and any
person disposing of sewage sludge in a
monofill. EPA developed numerical
limits on the concentration of 16
pollutants in sludge that could not be
exceeded if the sludge was disposed of
in a monofill. These limits, derived from
a modelled exposure pathway analysis,
would vary depending the type of
ground water under the unit. Moreover,
(lie proposal provided for the
determination of site-specific limits for
monofills in defined circumstances.
Surface Disposal
In addition to the disposal of sewage
sludge in sludge-only landfills, EPA also
developed standards for another widely
practiced means of sludge land disposal.
EPA called this disposal method
"surface disposal"—typically piles of
sludge placed on the land—and defined
them as areas of land where sludge is
placed for a year or longer. Because EPA
concluded that surface disposal sites are
generally small and in rural areas, these
sites did not expose individuals to
significant concentrations of pollutants.
EPA proposed pollutant concentration
limits for sludge placed on a surface
disposal site based on the 98th-
purcontile values derived from the data
on sewage sludge quality. The effect of
using 98th-percontile data was to cap
pollutant concentrations at the level of
quality represented by the data base.
EPA concluded that this would protect
public health and the environment
because analysis of aggregate effects of
sowngo sludge use and disposal showed
a low incidence of adverse health effects
associated with this method of disposal.
Because surface disposal and monofills
shored a number of common
characteristics, where the most stringent
numeric monofill limits exceeded the
OBth-percontile concentration, these
were substituted for the 98th-percentile
concentrations.
In addition, because of the similarity
of surface disposal to non-agricultural
land application of sludge and to
monofills, EPA committed to revisiting
for the final rule the issue of whether
distinguishing these different use and
disposal methods was appropriate.
Furthermore, EPA committed to develop
exposure assessment models to evaluate
potential risk to health and the
environment from surface disposal units
for the final rule.
Pathogen and Vector Attraction
Reduction Requirements
As noted, sewage sludge typically
includes contaminants like bacteria,
viruses, protozoa and helminth ova.
These organisms can cause diseases,
usually enteric diseases through direct
human contact with the organism or
through the ingestion of an infected
animal. These contaminants may be
spread by birds, rats and other animals
exposed to them. The proposal included
requirements for control of the
pathogens in sludge as well as measures
for reducing the contact of the disease
"vectors" with the sludge pathogens.
The proposal included pathogen
reduction and vector attraction
reduction requirements for sewage
sludge that is applied to agricultural and
non-agricultural land, distributed and
marketed or disposed of on a monofill
or surface disposal site.
In the proposal, treatment works
could use any one of three levels of
pathogen reduction when sewage sludge
is applied to either agricultural or non-
agricultural land as long as the
treatment works or applier complied
with the applicable restrictions on
public access to the land and on
growing crops or raising animals on the
sludge-amended soil. In addition, two
sets of numerical limits were included
in this part. The applicability of these
limits depended on whether the sewage
sludge is used in the production of
crops intended, directly or indirectly,
for human consumption or for animals
raised for human consumption.
One key difference between the
proposed requirements of subpart B
(land application) and subpart C
[distribution and marketing) was the
level of pathogen reduction in sludge
required for a treatment works. Under
the proposal, treatment works that
distribute and market their sewage
sludge to the general public had to
process their sludge to attain the highest
level of pathogen reduction provided. In
contrast, the land application subpart of
the proposal allowed a treatment works
the option of selecting alternative
pathogen reduction standards as long as
the landowner imposed public access
and animal grazing controls and
restricted the growing and harvesting of
crops in accordance with the standards
of the class of pathogen reduction
selected,
In developing the requirements for the
land application of sewage sludge, the
Agency assumed that, except for the
applier, there would be little public
contact with the sewage sludge itself or
with the land receiving the sewage
sludge. EPA also assumed that public
access restrictions could be imposed on
either agricultural or non-agricultural
land for a period of time. The
underlying premise in developing
sewage sludge distribution and
marketing requirements was that the
sludge would be used in a home garden
where there would be immediate and
continuous human contact with the
sewage sludge or with the land
receiving it. Under such circumstances,
the Agency could not restrict access.
Incineration
EPA proposed the following
requirements for sewage sludge that is
incinerated in an incinerator firing only
sewage sludge. First, the proposed rule
required a sludge incinerator to comply
with the National Emission Standards
for Hazardous Air Pollutants for
mercury and beryllium. Second, in the
case of lead, arsenic, cadmium,
chromium and nickel, the proposal
established a limit on the sludge
concentration of these metals that could
be incinerated. That concentration
would vary depending principally on
two factors: The control efficiency of the
incinerator, and the dispersion factor
(i.e., the relationship between ground
level concentrations and pollutant
emissions). These limits were designed
to ensure that ground level
concentrations (called the "risk-specific
concentration") for a given pollutant did
not exceed a value associated with
protection of human heath at a cancer
risk level of 10~5. In the case of lead,
the standard was designed to ensure
that the National Ambient Air Quality
Standard for lead was not violated. For
purposes of this calculation, sewage
sludge incinerators were assigned 25
percent of the air-shed loading for lead.
Third, the February 6,1989 notice
proposed a limit for maximum
allowable total hydrocarbon
concentration in sewage sludge. Again,
this limitation, like the metal limits
would vary with dispersion factors and
control efficiency. Similarly, it was
designed to ensure that ground level
concentrations of total hydrocarbon
emissions from the incinerator stack
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9267
would not exceed a level associated
with a cancer risk of 10 ~5. In order to
determine the risk-specific
concentration for total hydrocarbons,
EPA made a number of assumptions
about which organic pollutants
comprised the total hydrocarbon
mixture and at what levels these
drganics were present.
Monitoring, Recordkeeping and
Reporting
The proposal required owners and
operators of treatment works to sample
and analyze their sludge and keep
certain records. The pollutants for
which monitoring was required
depended on the method of sludge use
or disposal employed. The frequency of
monitoring would vary with the design
capacity of the treatment works. In
addition, treatment works were to
monitor the sewage sludge for
compliance with the pathogen reduction
requirements when the sludge was used
or disposed of other than by
incineration. Further, the proposal
required owners or operators of sewage
sludge incinerators to monitor
continuously for incinerator stack
hydrocarbon concentrations, sludge feed
rate, combustion temperature, and
oxygen content of the exit gas.
As noted, the proposal required an
agreement between the treatment works
and the distributor or land applier. The
information needed for the proposed
reporting requirements would be
contained in these agreements. EPA
proposed that treatment works applying
sewage sludge to agricultural lands keep
the records for the life of the treatment
works to ensure that the cumulative
pollutant loading rate is not exceeded
for a particular parcel of land receiving
sewage sludge.
The monitoring, recordkeeping, and
reporting requirements proposed for
non-agricultural lands were similar to
those required for agricultural lands.
One difference was that treatment works
did not have to keep track of annual and
cumulative pollutant loading rates.
Therefore, retention was only required
for 5 years.
The proposal required retention of the
analytical data on sewage sludge
concentrations and pathogen reduction
for 10 years for monofills and for five
years for surface disposal sites.
Incinerator records under the proposal
were required to be kept for 5 years.
Part V: November 9,1990 Notice of
Availability of Information and Data,
and Anticipated Impacts on Proposed
Rule
Subsequent to publication of the
proposed part 503 regulation in the
Federal Register, three data gathering
efforts were undertaken to gather
information for the final part 503
regulation. They include the National
Sewage Sludge Survey, a sewage sludge
incinerator study, and a domestic
septage sample collection and analytical
study. This part of today's preamble
describes those efforts briefly.
Background
Public Comment and Scientific Peer
Review
In the preamble to the part 503
proposal, the Agency solicited public
comment on a wide range of issues
including the fundamental principles of
the rule, the carcinogenic risk levels
used, other human health and
environmental criteria that could be
used in establishing the numerical
limits, changes that may occur because
of other Agency actions (e.g., changes in
MCLs and air standards for lead), the
models, the MEI and aggregate risk
analyses, the anticipated benefits and
costs of the rule, and data deficiencies.
In addition, EPA committed to seek and
support scientific peer review of the
technical bases of the rulemaking
package during the public comment
period on the proposed rule (54 FR
5747):
EPA will have experts from both inside
and outside the Agency review the scientific
and technical bases of the proposal. This
review may include the Agency's Science
Advisory Board, the Cooperative State
Research Service, Regional Research
Technical Committee (sometimes called the
W-170 Committee), representatives of
academia, and/or other scientific/technical
bodies with expertise in the areas covered by
this proposed rule. With the additional data
and the scientific and technical review of the
proposal, the Agency should he able to
expand and refine the standards.
The Agency worked with two peer
review groups during the public
comment period to review in detail the
scientific and technical bases of the
proposed rule. These two peer review
groups were as follows:
1. Land Practices Peer Review
Committee—The land application,
distribution and marketing, monofill
and surface disposal provisions of the
proposal were reviewed in depth by a
specially convened group of sewage
sludge experts. This group included
many nationally known experts on
sludge use and disposal including
several members of the U.S. Department
of Agricultural W-170 Committee and
represented a broad diversity of views.
A representative of the Natural
Resources Defense Council served on
this committee. The final report was
officially submitted to EPA on July 24,
1989 (Reference No. 58). Members of the
committee and their organizations
volunteered their time for this effort.
Contributions to travel expenses for
committee members were provided by
several outside organizations
(Association of metropolitan Sewerage
Agencies, Water Environment
Federation).
2. EPA Science Advisory Board
(SAB)—The SAB reviewed the technical
bases of the sludge incineration
regulations. In the past, various SAB
committees have reviewed the technical
bases of similar EPA incineration
regulations, most notably municipal
solid waste combustion and hazardous
waste incineration. The final report was
submitted on August 7,1989 (Reference
No. 97). A representative of the Natural
Resource Defense Council served on this
committee.
In addition to the two peer review
reports, EPA received in excess of 5,500
pages of comments from 656
commenters during the 183-day public
comment period on the proposed rule.
The type and number of commenters a
broken down as follows:
Municipalities
Industry
States
Septage haulers
Septage association
Consultants
Associations
Federal agencies
Individuals
Academic
Public interest
Congressional
Public hearing
are
Total:
278
51
36
36
3
34
29
17
16
12
9
72
63
656
The public and scientific peer review
groups provided a comprehensive range
of opinions, comments, and
recommendations. Many of the
comments were critical of the Agency's
risk assessment methodology (stating it
was overconservative for some use and
disposal practices, and under
conservative for others); the risk levels
used by the Agency (questioning which
risk levels are most appropriate, 10 ~4/
10 ~5 versus 10 ~6); the selection of data
and parameters used in the exposure
assessment analyses (providing
additional/better data and parameters);
and the impacts the proposed rule
would have on beneficial reuse of
sewage sludge.
On November 9,1990, EPA provided
public notice of the availability of the
National Sewage Sludge Survey data.
That notice described some of the
results of the survey. In addition, the
notice contained information and data
from the Sewage Sludge Incinerator
Study and the Domestic Septage Study,
and described the changes the Agency
-------
9268 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
was considering making to the proposed
part 503 regulation as a result of these
studies. Further, the notice requested
comments on a number of changes to
the use and disposal standards that were
being considered for the part 503
proposal in light of the comments
submitted earlier, peer review of the
Agency's effort and new information
developed since the February 8,1989
proposal. (55 FR 47210-47823).
The 60-day public comment period
for the notice closed on January 8,1991.
During that time, the Agency received
more than 1,000 pages of comments
from 153 commenters. Many of the
comments made by the commenters
supported the changes identified in the
notice as revisions that the Agency was
considering for the final part 503 rule.
Need for Information on Current
Sewage Sludge Quality and Use and
Disposal Practices
The "'JO City Study" Data Base
As required by section 405(d), EPA
rolled on available information in
developing proposed 40 CFR part 503.
The primary source of information on
the occurrence and concentration of
pollutants in sewage sludge was
determined from analyzing data on 40
pollutants from POTWs in 40 cities ("40
City Study"—Reference No. 60).
As discussed earlier, at the time of
proposal the Agency relied on the "40
City Study" data as the primary source
of information on the pollutant
concentrations in municipal sewage
sludge. The "40 City Study" provided
the most comprehensive and best
documented nationwide data base on
the concentrations of pollutants in
sewage sludge. Consequently, EPA
concluded these data were an
appropriate basis for developing the
proposal. However, EPA recognized
several deficiencies in using the "40
City Study" data. Key among them was
the fact that data on final processed
sewage sludge was generally not
available from the "40 City Study."
Further, the procedure used to select
POTWs in the "40 City Study" did not
follow the statistical methods required
to support unbiased national estimates
of pollutant concentrations in POTW
sewage sludge.
The study was designed not to
measure pollutant concentrations in the
sewage sludge leaving a POTW, but to
determine what happened to section
307(a)(l) priority toxic pollutants in
POTWs employing secondary or
advanced treatment. The study
approach required that some sewage
sludge samples be taken at points
within the POTW prior to final sewage
sludge processing in order to account
for organic pollutants that may be
transformed into more elementary
compounds or gases before final sewage
sludge processing, as in anaerobic
digestion. However, the study did
include information that enabled the
Agency to estimate the dry weight
concentrations of pollutants in POTW
sewage sludge.
Another deficiency of the data from
the "40 City Study" is that they are not
current. Sewage sludge quality had
changed since 1978, because of the
initiation of many pretreatment
programs, development of new
industrial facilities discharging
wastewater to the POTW, and changes
in wastewater treatment processes.
Therefore, pollutant concentrations
from the "40 City Study" did not reflect
the current quality of sewage sludge.
Moreover, analytical method
advancements since the "40 City Study"
allow for more accurate analyses of
pollutants in the presence of suspended
solids.
Although other sources of data on
sewage sludge quality existed, these also
suffered from deficiencies rendering
them unsuitable for regulatory purposes.
Some data were drawn from too narrow
a geographic area or were drawn from
POTWs of a particular size. Frequently,
these data were not collected
systematically and different sampling
and analytical protocols were used in
the same survey. In addition, many of
these other data were collected prior to
the "40 City Study" data.
While EPA believed that the "40 City
Study" data were the appropriate data
to use in developing the proposed part
503 regulations, EPA concluded the data
needed to be replaced, or at a minimum,
be supplemented to support the final
regulations. Therefore, EPA undertook
the NSSS to obtain a current and
reliable data base for developing the
final part 503 rule. This data base, as
previously explained, will also be used
in developing a list of pollutants from
which the Agency will select additional
pollutants for further analyses and
potential regulation under section
405(d)oftheCWA.
The NSSS data collection effort began
in August 1988 and was completed in
September 1989. EPA collected sewage
sludge samples at 180 POTWs and
analyzed them for more than 400
pollutants. In addition, through the use
of detailed questionnaires, the survey
collected information on sewage sludge
use and disposal practices from 475
public treatment facilities with at least
secondary treatment of wastewater. The
results of the NSSS have provided EPA
current data and information essential
to establishing numerical pollutant
limits in the final part 503 rule that will
encourage the beneficial reuse of sewage
sludge and provide a greater degree of
public health and environmental
protection than the February 6,1989,
proposal.
The National Sewage Sludge Survey
The NSSS, a massive undertaking,
was conducted to obtain credible
analytical data in order to characterize
the quality of final process sewage
sludge (55 FR 47210, November 9,
1990). These data were used to develop
national estimates for the probability
distribution of pollutant concentrations
in sewage sludge. The estimates of
pollutant distribution were used in
developing the regulatory impact
analysis for the final part 503 rule. EPA
augmented sewage sludge quality data
with information concerning sewage
sludge generation and treatment
processes, current and alternative
sewage sludge use and disposal
practices, and treatment and disposal
cost data. These data, from a national
sampling of POTWs employing
secondary or advanced treatment of
wastewater, were necessary for a
number of essential analyses required
for promulgating the final part 503
regulations including the aggregate risk
analysis (ARA) and the regulatory
impact analysis (RIA) which project the
benefits and expected effects associated
with the final part 503 rule. The ARA
and the RIA are discussed later in part
XIII.
In establishing numerical limits,
pollutant concentration data from the
NSSS were required to estimate the
level of risk posed by current sewage
sludge quality and current use or
disposal practices. EPA also used the
data from the survey to test the
reasonableness of its analyses and
regulatory approach. Some areas of
earlier concern included the accuracy of
anticipated risks and analyzed
characteristics of increased incidence of
chemically induced disease in
proximity to particular use or disposal
practices. The survey information
assisted the Agency in further
evaluating its regulatory approach and
in capping those pollutants at the 99th-
percentile pollutant concentration
where the Agency believes the strictly
risk-based numerical limitations do not
provide an adequate margin of safety to
protect public health and the
environment.
The results of the survey were also
used to assess the potential shifts among
the various use or disposal practices as
a result of the final regulations. The
effect of the rule is an important
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9269
element in determining how rapidly to
implement the regulations. For instance,
if there is likely to be only a slight
impact from a particular numerical
limitation, immediate implementation
of the regulations may be appropriate. If,
on the other hand, wide shifts in current
methods of use or disposal are
anticipated from the numerical limits,
the POTWs may need assistance in
developing more stringent pretreatment
limits for their industrial dischargers or
in the adoption of alternative use or
disposal practices.
In addition, EPA will study the
analytical results of the NSSS to identify
a preliminary list of pollutants for
second round rulemaking. Potential
candidate pollutants are those that have
elevated concentrations in sewage
sludge. A final decision to regulate
pollutants in the second round will
significantly depend on the availability
of sufficient information on a pollutant's
toxicity and environmental fate, effect,
and transport properties. As explained
earlier, the process EPA will follow to
identify these pollutants will be similar
to the process used in developing the
pollutants controlled in this rulemaking.
Description of the National Sewage
Sludge Survey
The NSSS was a data collection effort
relying on analytical sampling and an
informational questionnaire to obtain
data on sewage sludge quality and
management. The NSSS was designed to
collect information and data necessary
to produce national estimates of: (1)
Concentrations of toxic pollutants in
municipal sewage sludge, (2) sewage
sludge generation and treatment
processes, (3) sewage sludge use and
disposal practices and alternative use
and disposal practices, and (4) sewage
sludge treatment and disposal costs.
Participants in the NSSS were
selected from 11,407 POTWs in the
United States, Puerto Rico, and the
District of Columbia, identified in the
EPA 1986 Needs Survey as having at
least secondary wastewater treatment.
Secondary treatment was defined as a
primary clarification process followed
by biological treatment and secondary
clarification. In identifying POTWs for
the NSSS, EPA excluded POTWs with
"Present Effluent Characteristics" codes
of "No Discharge," "Raw Discharge,"
and "Advanced Primary" from the 1986
Needs Survey.
As noted above, the NSSS effort
consisted of a questionnaire and
analytical survey. The sample of POTWs
for each component was selected from
the 11,407 secondary treatment POTWs
identified by the Agency. The POTWs
included in the two samples were
selected according to stratified
probability design. The two POTW
samples are related in that all POTWs in
the analytical survey were selected from
among those POTWs that were already
selected to receive the questionnaire.
The questionnaire survey was
designed to allow survey results to be
analyzed separately by flow rate group
and by sewage sludge use and disposal
practice. The secondary treatment
POTWs identified by the Agency were
divided into 24 mutually exclusive
groups. Membership in these groups is
based on four categories of wastewater
flow rate and six primary use and
disposal practices. The flow rates and
use and disposal categories are as
follows:
1. POTW average daily flow rate
categories:
a. Flow less than or equal to one
million gallons per day (MGD).
b. Flow more than one MGD but less
than or equal to 10 MGD.
c. Flow more than 10 MGD but less
than or equal to 100 MGD.
d. Flow greater than 100 MGD.
2. POTW sewage sludge use and
disposal practice groups:
a. Land application.
b. Distribution and marketing.
c. Incineration.
d. Monofill (sewage sludge only
landfill).
e. Ocean disposal.
f. Co-disposal landfill and other.
A 50-page questionnaire was mailed
to every POTW selected for the NSSS.
A total of 479 POTWs were selected to
receive the questionnaire. General
information gathered by the
questionnaire concerned service area,
POTW operating information, general
sewage sludge use and disposal
practices, pretreatment activities,
wastewater and sewage sludge testing
frequencies, and POTW financial
information. POTWs also supplied use
and disposal practice specific
information and indicated which
practice(s) would be likely alternatives
to current use and disposal practices.
POTWs in the analytical survey were
restricted to the contiguous States and
the District of Columbia. The POTWs in
the analytical survey were drawn from
those included in the questionnaire
survey. A total of 208 POTWs from the
four flow rate categories were selected
for sampling and analysis. EPA contract
personnel collected sewage sludge
samples just prior to disposal from each
POTW according to sampling and
preservation protocols.
Samples were analyzed for a total of
412 analytes. These analytes included
every organic, pesticide, dibenzofuran,
dioxin and PCB for which EPA has gas
chromatography and mass spectrometry
(GC/MS) standards. The remaining
pollutants are inorganics. The pollutants
were also selected in consideration of:
(1) The CWA section 307(a) priority
pollutants, (2) toxic compounds
highlighted in the Domestic Sewage
Study, and (3) Resource Conservation
and Recovery Act (RCRA, Pub. L. 94-
580) appendix Vin pollutants.
Sewage sludge sampling,
preservation, and analytical protocols
were specifically developed for this
survey. Analytical methods 1624 and
1625 were adapted from methods to
deal specifically with the sludge matrix
for volatile and semivolatile organics,
respectively, and utilize gel permeation
chromatography sample clean-up
followed by isotope dilution gas
chromatography-mass spectrometry
analyte identification and
quantification. Pesticides and PCBs, and
dibenzofurans and dioxins were
analyzed using analytical methods 1618
and 1613, respectively. Metals and other
inorganics and classicals were analyzed
by standard EPA methods. The
analytical methods were either
developed, chosen, or adapted
specifically for the sludge matrix to give
the most reliable, accurate, and precise
measurements of the 412 analytes
undertaken in any previous analytical
survey.
All raw analytical results were
subjected to a two-step quality
assurance/quality control (QA/QC)
procedure. In the first step, each result
and analytical procedure was checked
against analytical method specifications.
If this step was satisfied, then the result
was evaluated for potential outlier
characteristics by checking on
laboratory identification number
validity as well as sample origin. If the
sample raw data passed both of these
checks, it was certified and reported to
EPA. Information on the availability of
the NSSS data base and analytical
protocols is provided in Part XIV—
Availability of Technical Information on
the Final Rule.
Sewage Sludge Incinerator Field
Studies
In 1987, the Agency initiated a series
of field studies on sewage sludge
incinerators to support the part 503
rulemaking effort. The purposes of the
on-site tests were to obtain: (1)
Information about the percentage of
hexavalent chromium in the total
chromium in the exit gas from a sewage
sludge incinerator, (2) information on
the percentage of nickel subsulfide in
the total nickel in the exit gas from a
sewage sludge incinerator, (3) total
-------
9270 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
hydrocarbon (THC) emissions data for
the sowago sludge incinerators, and (4)
information about organic compounds
in the exit gas from a sewage sludge
incinerator.
As part of the studies, information
was collected at 10 sewage sludge
incinerators. Eight of the incinerators
wore multiple hearth incinerators and
one was a iluidized bed incinerator. The
incinerators had various combinations
of air pollution control devices
including wet scrubbers and wet
electrostatic precipitators.
For the final rule, risk-specific
concentrations are used to develop
allowable pollutant concentrations for
metals in sewage sludge. The risk-
specific concentration for chromium
depends on the percentage of
hexavalent chromium in the total
chromium in the exit gas. Based on tests
at several sewage sludge incinerators,
the Agency determined that the
conversion to hexavalent chromium
varies with the type of sewage sludge
incinerator and air pollution controls.
From the results, EPA derived different
risk-specific concentration values
(shown in Table 2 of section 503.43 of
today's final part 503 regulation) based
on four combinations of sewage sludge
incinerators and air pollution control
technologies.
The results of the nickel speciation
tests revealed that nickel subsulfide is
not emitted from sewage sludge
incinerators above the level of detection
for the analytical methods used in the
tests. In order to be protective, EPA
decided to base the standard risk-
specific concentration for nickel on the
higher of two detection limit values for
nickel subsulfide. The risk-specific
concentration for nickel in Table 1 of
section 503.43 of today's final part 503
regulation is based on there being 10
percent nickel subsulfide in total nickel
emitted from a sewage sludge
incinerator.
Data from the studies on the total
hydrocarbon concentration in the exit
gas from sewage sludge incinerators
were used, along with the aggregate risk
analysis, as the basis for the THC
operational standard in today's final
part 503 regulation. This standard is
technology-based in that it is based on
performance data from sewage sludge
incinerators. The THC operational
standard is partly based on THC
omissions measured using a heated
sampling line and corrected to seven
percent oxygen and zero percent
moisture.
Information on total organic
pollutants and THC in the exit gas from
the sewage sludge incinerator was the
basis for THC being used as a surrogate
for measuring organic compounds in the
exit gas. These tests showed that there
is a significant correlation between THC
and organic compounds, which is
important because sampling and
analysis techniques are not available to
identify or quantify all potential organic
compounds emitted from sewage sludge
incinerators, nor are toxicity data
available for all compounds. In
addition, THC is easier and less
expensive to monitor than are total
organics, and THC can be measured on
a continuous basis, which enhances
operating and management practices.
Further, information on the organic
pollutants in the exit gas from the
sewage sludge incinerator was used to
judge whether the technology-based
THC limit protects public health and the
environment from the reasonably
anticipated adverse effects of organic
pollutants in sewage sludge. Knowing
which organic pollutants are in the exit
gas (or potentially in the exit gas)
allowed the Agency to develop an
ambient risk-specific concentration for
the organic compounds. This value was
then used to estimate the risk level for
the technology-based THC limits, which
is an exit gas concentration.
The sewage sludge incinerator tests
were also used to demonstrate that (1)
wet electrostatic precipitators were
effective at controlling metals
emissions, (2) improved incinerator
operating procedures and afterburners
were effective at controlling THC
emissions, and (3) THC analyzers were
reliable instruments for measuring THC
in the exit gas. More details on the
sewage sludge incinerator field studies
may be found in the Technical Support
Document for Incineration. Information
on the availability of single copies of
this and other technical support
documents is provided in part XIV.
Domestic Septage Study
In 1991, EPA initiated a sampling and
analysis study for domestic septage. The
purpose of this study was to
characterize domestic septage. It was
conducted because data on organic
pollutants in domestic septage were not
available.
As part of the study, nine samples of
domestic septage were collected and
analyzed for over 400 pollutants. These
samples were collected and preserved in
accordance with approved protocols.
Analytical results from this study
were used for two purposes. First, the
total Kjeldahl nitrogen and ammonia
concentrations in the domestic septage
were used to calculate the factor in the
annual application rate equation for
domestic septage in the final part 503
regulation. Second, the data were used
in the justification of the domestic
septage annual application rate.
More details on the domestic septage
study and how it was used in
developing the final regulation may be
found in the Technical Support
Document for Land Application.
Information on the availability of single
copies of this and other technical
support documents is provided in Part
XIV—Availability of Technical
Information on the Final Rule.
Part VI: Risk Assessment Methodology
The purpose of risk assessment for
EPA is to identify the potential for
adverse effects associated with a
pollutant in order to determine what, if
any, measures are needed to protect
public health and the environment.
EPA, in developing these use and
disposal standards, evaluated the
potential risk to public health or the
environment from individual pollutants
present in sewage sludge. In performing
this assessment, EPA relied on its
traditional risk assessment processes
and tools.
The methods for performing a risk
assessment used by EPA were originally
outlined by the National Academy of
Sciences (NAS, 1983—Risk Assessment
and Management: Framework for
Decision Making. Washington, DC) and
published in the Federal Register. EPA
followed the following guidelines in its
work in developing these regulations:
U.S. EPA, 1986a—Guidelines for
Carcinogen Assessment; Guidelines for
Estimating Exposure; Guidelines for
Mutagenicity Risk Assessment;
Guidelines for Health Assessment of
Suspect Developmental Toxicants; and
Guidelines for Health Risk Assessment
of Chemical Mixtures. FR Vol. 51, No.
185.
EPA's methodology for risk
assessment may be broken down into
four stages: hazard identification, dose-
response evaluation, exposure
evaluation, and characterization of risks.
These are explained below.
Hazard Identification
The first element in this process is
hazard identification—a determination
of the nature of the effects that may be
experienced by an exposed human or
ecosystem from an identified pollutant.
Hazard identification is used to
determine whether the pollutant poses a
hazard and whether sufficient
information exists to perform a
quantitative risk assessment. Hazard
identification consists of gathering and
evaluating all relevant data that help
determine whether a pollutant poses a
specific hazard, then qualitatively
evaluating those data on the basis of the
-------
Federal Register /Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9271
type of health effect produced, the
conditions of exposure, and the
metabolic processes that govern
pollutant behavior within the body or
organism. It may also involve
characterization of the behavior of a
pollutant in the environment (or within
an organism) as well as interactions the
pollutant may undergo within the
environment or within an organism.
Thus, hazard identification helps to
determine whether it is appropriate
scientifically to infer that effects
observed under one set of conditions
(e.g., in experimental animals) are likely
to occur in other settings (e.g., in human
beings), and whether data are adequate
to support a quantitative risk
assessment.
The first step in hazard identification
is to gather information on the toxic
properties of pollutants through animal
studies and controlled epidemiological
investigations of exposed human
populations.
The use of animal toxicity studies is
based on the longstanding assumption
that effects in human beings can be
inferred from effects in animals. Three
categories of animal bioassay are: Acute
exposure tests, subchronic tests, and
chronic tests. The usual starting point
for such investigations is the study of
acute toxicity in experimental animals.
Acute exposure tests expose animals to
high doses for short periods of time,
usually 24 hours or less. The most
common measure of acute toxicity is the
median lethal dose (LD50), defined as
the dose level that is lethal to 50 percent
of the test animals. This dose is usually
experimentally determined by
administering the test compound orally
or intraperitoneally to mice or rats. Less
commonly, tests can also be conducted
by administering the pollutant by
inhalation, dermal exposure or
intravenously. LD50 is also used for
aquatic toxicity tests and refers to the
concentration of the test substance in
the water that results in 50 percent
mortality in the test species. Substances
exhibiting a low LD50 (e.g., for sodium
cyanide, 6.4 mg/kg) are more acutely
toxic than those with higher values (e.g.,
for sodium chloride, 3,000 mg/kg)
(NIOSH, 1979—Registry of Toxics
Effects of Chemical Substances).
Subchronic tests for pollutants
involve repeated exposures of test
animals for 5 to 90 days, depending on
the animal, by exposure routes
corresponding to human exposures. The
tests are used to determine the No
Observed Adverse Effect Level
(NOAEL), the Lowest Observed Adverse
Effect Level (LOAEL), and the
Maximum Tolerated Dose (MTD). The
MTD is the largest dose a test animal
can receive for most of its lifetime
without demonstrating adverse effects
other than cancer. In studies of chronic
effects of pollutants, test animals receive
daily doses of the test agent for
approximately 2 to 3 years. The doses
are lower than those used in acute and
subchronic studies and the number of
animals is larger because these tests are
trying to detect effects that will be
observed in only a small percentage of
animals.
The second method of evaluating
health effects uses epidemiology—the
study of patterns of disease in human
populations and the factors that
influence these patterns. In general,
scientists view well-conducted
epidemiological studies as the most
valuable information from which to
draw inferences about human health
risks. Unlike the other approaches used
to evaluate health effects,
epidemiological methods evaluate the
direct effects of hazardous substances
on human beings. These studies also
help identify human health hazards
without requiring prior knowledge of
what causes disease, and they
complement the information gained
from animal studies.
Epidemiological studies compare the
health status of a group of persons who
have been exposed to a suspected causal
agent with that of a comparable
nonexposed group. Most
epidemiological studies are either case-
control studies or cohort studies. In
case-control studies, a group of
individuals with a specific disease is
identified (cases) and compared with
individuals not having the disease
(controls) in an attempt to find past
commonalities in exposures. Cohort
studies start with a group of people (a
cohort) considered free of the specific
disease. The health status of the cohort
known to have a common exposure is
examined over time to determine
whether any specific condition or cause
of death occurs more frequently than
might be expected from other causes.
Epidemiological studies are well
suited to situations in which exposure
to the risk agent is relatively high; the
adverse health effects are unusual (e.g.,
rare forms of cancer); the symptoms of
exposure are known; the exposed
population is clearly defined; the link
between the causal risk agent and
adverse effects in the affected
population is direct and clear; the risk
agent is present in the bodies of the
affected population; and high levels of
the risk agent are present in the
environment.
The next step in hazard identification
is to combine the pertinent data to
ascertain the degree of hazard associated
with each pollutant. In general, EPA
uses different approaches for
qualitatively assessing the risk or hazard
associated with carcinogenic versus
noncarcinogenic effects. For
noncarcinogenic health effects (e.g.,
mutagenic effects, systemic toxicity), the
Agency's hazard identification/weight-
of-evidence determination has not been
formalized and is based on qualitative
assessment.
EPA's guidelines for carcinogenic risk
assessment (U.S. EPA, 1986a) group all
human and animal data reviewed into
the following categories based on degree
of evidence of carcinogenicity:
• Sufficient evidence.
• Limited evidence (e.g., in animals,
an increased incidence of benign tumors
only).
• Inadequate evidence.
• No data available.
• No evidence of carcinogenicity.
Human and animal evidence of
carcinogenicity in these categories is
combined into the following weight-of-
evidence classification scheme:
• Group A—Human carcinogen
• Group B—Probable human carcinogen
Bl—Higher degree of evidence
B2—Lower degree of evidence
• Group C—Possible human carcinogen
• Group D—Not classifiable as to
human carcinogenicity
• Group E—Evidence of
noncarcinogenicity
Group B, probable human carcinogen,
is usually divided into two subgroups:
Bl—pollutants for which some limited
evidence of carcinogenicity from
epidemiology studies exists, and B2—
pollutants for which sufficient evidence
exists from animal studies but
inadequate evidence exists from
epidemiology studies. EPA treats
pollutants classified in categories A and
B as suitable for quantitative risk
assessment. Pollutants classified as
Category C receive varying treatment
with respect to dose-response
assessment (see discussion below), and
they are determined on a case-by-case
basis. Pollutants in Groups D and E do
not have sufficient evidence to support
a quantitative dose-response
assessment.
The following factors are evaluated by
judging the relevance of the data for a
particular pollutant:
• Quality of data.
• Resolving power of the studies
(significance of the studies as a function
of the number of animals or subjects).
• Relevance of route and timing of
exposure.
• Appropriateness of dose selection.
• Replication of effects.
• Number of species examined.
-------
9272 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
• Availability of human
opidomiologic study data.
Although the information gathered
during tho course of identifying each
pollutant hazard is not used to estimate
risk quantitatively, hazard identification
enables researchers to characterize the
body of scientific data in such a way
that two questions can be answered: (1)
Is a pollutant a hazard? and (2) Is a
quantitative assessment appropriate?
The following two sections discuss how
such quantitative assessments are
conducted.
Dose-Response Evaluation
Estimating or evaluating the dose-
response relationships—what "dose" of
a chemical produces a given
"response"—for the pollutant under
review is the second step in the risk
assessment methodology. Evaluating
dose-response data involves
quantitatively characterizing the
connection between exposure to a
pollutant (measured in terms of quantity
and duration) and the extent of toxic
injury or disease. Most dose-response
relationships are estimated based on
animal studies, because even good
epidemiological studies rarely have
reliable information on exposure.
Therefore, this discussion focuses
primarily on dose-response evaluations
based on animal data.
Two general approaches to dose-
response evaluation are used,
depending on whether the health effects
ore based on threshold or nonthreshold
characteristics of the pollutant. In this
context, "threshold" refer to exposure
levels below which no adverse health
effects are assumed to occur. For effects
that involve altering genetic material
(including carcinogenicity and
mutagenicity), the Agency's position is
that effects may take place at very low
doses; therefore, they are modeled with
no thresholds. For most other biological
effects, it is usually, but not always,
assumed that threshold levels exist.
For nonthreshold effects, the key
assumption is that the dose-response
curve for such pollutant exhibiting these
effects in the human population
achieves zero risk only at zero dose. A
mathematical model is used to
extrapolate response data from doses in
tho observed (experimental) range to
response estimates in the low-dose
ranges. Scientists have developed
several mathematical models to estimate
low-dose risks from high-dose
experimental risks. Each model is based
on general theories of carcinogenesis
rather than on data for specific
pollutants. The choice of extrapolation
model can have a significant impact on
the dose-response estimate. For this
reason, the Agency's cancer assessment
guidelines recommend the use of the
multistage model, which yields
estimates of risk that are conservative,
representing a plausible upper limit of
risk. With this approach, the estimate of
risk is not likely to be lower than the
true risk (U.S. EPA, 1986a).
The potency value, referred to by the
Carcinogenic Assessment Group as Qi*
(also referred to as Q*), is the
quantitative expression derived from the
linearized multistage model that gives a
plausible upper-bound estimate to the
slope of the dose-response curve in the
low-dose range. The QJ* is expressed in
terms of risk-per-dose and has units of
(mg/kg/day)"1. These values should be
used only in dose ranges for which the
statistical dose-response extrapolation is
appropriate. EPA's Qi * values can be
found in the Integrated Risk Information
System (IRIS), accessible through the
National Library of Medicine. IRIS is
EPA's computerized data base on health
effects for carcinogenic and non-
carcinogenic pollutants and contains the
Agency's Qi* and RfD values for these
pollutants.
Systemic toxicants or other
compounds exhibiting noncarcinogenic
and nonmutagenic health effects are
assumed to exhibit threshold effects.
Dose-response evaluations for
substances exhibiting threshold
responses involve calculating what is
known as the Reference Dose (oral
exposure) or Reference Concentration
(inhalation exposure), abbreviated to
RfD and RfC, respectively. RfDs and
RfCs are estimates of a daily exposure to
the human population that is likely to
be without appreciable risk of
deleterious effects during a lifetime. The
RfDs and RfCs developed by EPA can be
found in IRIS.
No Observed Effect Level (NOEL), No
Observed Adverse Effect Level
(NOAEL), Lowest Observed Effect Level
(LOEL), or Lowest Observed Adverse
Effect Level (LOAEL) can be used to
calculate RfDs and RfCs values. Each
value is stated in mg/kg/day, and all the
values are derived from laboratory
animal and human epidemiology data.
Uncertainty factors are applied to RfD
and RfC values depending on the level
of confidence the Agency has in the data
used to derive them. The magnitude of
uncertainty factors varies according to
the nature and quality of the data from
which the NOAEL or LOAEL is derived.
The uncertainty factors range from 10 to
10,000. They are used to extrapolate
from acute to chronic effects, to account
for differences in species sensitivity or
variation in sensitivity in human
populations and, when appropriate, to
extrapolate from a LOAEL to a NOAEL.
Ideally, route-specific (e.g., exposure
through dermal contact, inhalation, etc.)
RfDs and RfCs should be developed. If
information is available for only one
route of exposure, this information is
used to extrapolate to other routes. Once
an RfD or RfC is derived, the next step
in the risk assessment is to estimate
actual human (or animal) exposure.
Exposure Evaluation
The first step in exposure evaluation
is to estimate environmental
concentrations of pollutants. The
Agency relies on two methods to
determine pollutant concentration:
(1) Directly monitoring levels of
pollutants, and
(2) Using mathematical models to
predict pollutant concentrations.
Once environmental pollutant
concentrations are determined, the
Agency must then determine the
severity of the exposure. In this step, the
Agency evaluates data on the nature and
size of the population exposed to a
pollutant, the route of exposure (i.e.,
oral, inhalation, dermal), the extent of
exposure (concentration times time),
and the circumstances of exposure.
Monitoring
Monitoring involves collecting and
analyzing environmental samples.
These data provide the most accurate
information about pollutant
concentrations. The two kinds of
exposure monitoring are personal
monitoring and ambient (or site and
location) monitoring.
Most exposure assessments are
complicated in that people move from
place to place and are therefore exposed
to different pollutants throughout the
day. Some exposure assessments
attempt to compensate for this
variability by personal monitoring.
Personal monitoring uses one or more
techniques to measure the actual
concentrations of hazardous substances
to which individuals are exposed. One
technique is sampling air and water.
The amount of time spent in various
microenvironments (i.e., home, car, or
office), may be combined with data on
environmental concentrations of risk
agents in those mircroenvironments to
estimate exposure.
Personal monitoring may also include
the sampling of human body fluids (e.g.,
blood, urine, or semen). This type of
monitoring is often referred to as
biological monitoring or biomonitoring.
Biological markers (also called
biomarkers) can be classified as markers
of exposure, of effect, and of
susceptibility. Biological markers of
exposure measure exposure either to the
exogenous material, its metabolite(s), or
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9273
to the interaction of the xenobiotic agent
with the target cell within an organism.
An example of a biomarker of exposure
is lead concentration in blood. In
contrast, biologic markers of effect
measure some biochemical, physiologic,
or other alteration within the organism
that points to impaired health.
(Sometimes the term biomonitoring is
also used to refer to the regular
sampling of animals, plants, or
microorganisms in an ecosystem to
determine the presence and
accumulation of pollutants, as well as
their effects on ecosystem components.)
Ambient monitoring (or site or
location monitoring) involves collecting
samples from the air, water, soil, or
sediments at fixed locations, then
analyzing the samples to determine
environmental concentrations of
hazardous substances at the locations.
Exposures can be further evaluated by
modeling the fate and transport of the
pollutants.
Modeling
Measurements are a direct and
preferred source of information for
exposure analysis. However, such
measurements are expensive and are
often limited geographically. The best
use of such data is to calibrate
mathematical models that simulate the
movement of pollutants into and
through the environment with
mathematical equations or algorithms
that can be more widely applied.
Estimating concentrations using
mathematical models must account not
only for physical and chemical
properties related to fate and transport,
but must also document mathematical
properties (e.g., analytical integration
vs. statistical approach), spatial
properties (e.g., one, two, or three
dimensions), and time properties
(steady-state vs. nonsteady-state).
Hundreds of models for fate,
transport, and dispersion from the
source are available for all media.
Models can be divided into five general
types by media: atmospheric models,
surface-water models, ground water and
unsaturated-zone models, multimedia
models, and food-chain models. These
five types of models are primarily
applicable to pollutants or to radioactive
materials associated with dusts and
other particles.
Selecting a model for a given situation
depends on the following criteria:
Capability of the model to account for
important transport, transformation, and
transfer mechanisms; fit of the model to
site-specific and substance-specific
parameters; data requirements of the
model, compared to availability and
reliability of off-site information; and
the form and content of the model
output that allow it to address important
questions regarding human exposures.
To the extent possible, selection of the
appropriate fate and transport model
should follow guidelines specified for
particular media where available; for
example, the Guidelines on Air Quality
Models (U.S. EPA, 1986b—Guidelines
on Ah- Quality Models (Revised), EPA/
OAQPS-450/2-78-027R.).
Population Analysis
Population analysis involves
describing the size and characteristics
(e.g., age/sex distribution), location (e.g.,
workplace), and habits (e.g., food
consumption) of potentially exposed
human and nonhuman populations.
Census and other survey data often are
useful in identifying and describing
populations exposed to a pollutant.
Integrated exposure analysis involves
calculating exposure levels, along with
describing the exposed populations. An
integrated exposure analysis quantifies
the contact of an exposed population to
each pollutant under investigation via
all routes of exposure and all pathways
from the sources to the exposed
individuals. Finally, uncertainty should
be described and quantified to the
extent possible.
Risk Characterization
It is EPA policy to describe statements
about risks in major regulatory and
policy documents to convey the extent
of the Agency's confidence in those risk
estimates. Risk assessment information
must be clearly presented, separate from
any risk management considerations.
EPA seeks to present information on the
range of exposures and risks and to
identify all major uncertainties and
address their influence on the
assessment.
One way to identify uncertainties in
risks is to evaluate how exposure
assessments were conducted. For
example, in human health risk
assessment for this rule, the technical
support documents define several
exposure pathways for the three sludge
management practices. EPA used point
estimates for each exposure pathway
and did not consider variability of the
parameters describing exposure among
individuals.
EPA's confidence in the risk
assessment is necessarily limited by the
data available to the EPA and by the
lack of accepted risk assessment
methodologies in certain areas. Overall,
it is difficult to judge whether the point
estimates in the human health risk
assessment and assumptions made in
the ecological effects assessment are
likely to underestimate or overestimate
actual risks. Some aspects of the risk
analysis may contain conservative or
protective assumptions, while other
factors may bias results in the opposite
direction. In addition, some
assumptions are based on longstanding
Agency policy and reflect risk
management choices. Again, some of
these assumptions are conservative
while others are less conservative.
The sections that follow examine the
uncertainties in several important
aspects of the risk assessment: human
health, human exposure pathway, plant
toxicity and uptake, effects on wildlife,
and ground water impacts.
Human Health Assessment
In accordance with standard Agency
practice, human-health dose-response
assessments are based on reference
doses (RfDs) for non-carcinogens and
cancer potency factors (Qi*J for
carcinogens. Both of these measures are
generally considered conservative, that
is, they predict a greater impact on
human health than is likely to actually
occur. The reference dose is defined as
"an estimate (with uncertainty spanning
perhaps an order of magnitude) of a
daily exposure to the human population
(including sensitive subgroups) that is
likely to be without appreciable risk of
deleterious effects during a lifetime". It
is calculated by taking the most
sensitive adverse effect found in
toxicological testing and applying a
series of uncertainty factors, so that
higher exposures may also not present
any appreciable risk. It is assumed, for
example, that humans may be an order
of magnitude more sensitive than the
animals tested, but in fact humans may
also be less sensitive. It is also assumed,
except as noted, in the risk assessments
relied on for these regulations that
exposures may last an entire lifetime,
whereas they may in fact be much
shorter.
Similarly, calculated cancer risks are
described in the Agency's risk
assessment guidelines as "plausible
upper bounds" to the actual risk.
Conservative assumptions are used in
the calculations, such as use of the most
sensitive animal data in bioassays,
linear extrapolation to low doses,
species-to-species conversion based on
surface area, and use of an upper
confidence limit for the dose-response
slope. Thus, it is unlikely that the
cancer risk would be greater than is
calculated, but it could be orders of
magnitude less or even zero.
Human Exposure Assessment
There are uncertainties concerning
the long-term behavior of metals in
sludge. The sludge experts that EPA
-------
9274 Federal Register /Vol. 58, No. 32 /Friday, February 19, 1993 / Rules and Regulations
rolled on conclude, based on field
studios, that iron oxides and manganese
oxides found in sludge as a result of
wastowator treatment and metal oxides
naturally found in soils may form
complexes with the metals and
significantly reduce their
bioavailability. Documentation to
support these conclusions is limited. At
a minimum, when the organic
component of the sludge breaks down,
it is possible that average concentrations
of pollutants may increase or they may
become more bioavailable.
The risk assessment for the soil
ingestion pathway assumes the child
ingests 0.2 grams of undiluted sludge
every day for a five-year period, and has
a "typical" background intake of the
contaminants. The Agency has
determined that this assumption is
conservative and will protect children
who inadvertently ingest sewage sludge.
The exposure assessment for many
pathways assumes that the sludge will
bo fully incorporated into the top six
inches of soil, although there is no
labeling requirement to provide these
instructions on sludge products.
Home Garden Scenario
The Agency characterized the data
and assumptions used for exposure
analysis in the human food chain
pathway; specifically the calculations
for production of crops for home
consumption by gardeners and farmers.
The population assessed for this
pathway were individuals who use
sludge products to produce crops for
their own consumption. Ideally, the
Agency would like to describe the
distribution of exposures within this
population. However, the available data
oro insufficient for such an analysis. The
Agency made specific assumptions
about a number of variables addressing
human behavior and properties of
sludge.
Plant Uptake of Metals
Tho slope of the line for the plant
uptake was used to estimate metal
concentration in plants. Plant uptake of
metals was considered proportional to
the cumulative application rates. An
uncertainty exists whether it is
appropriate to calculate plant
concentration as a slope of plant uptake
times an application rate. Some data on
plant concentration versus application
rnto suggest non-linearities. EPA's
assessment assumes that the linear
approximation is conservative because
application rates allowed under the rule
ore in general well in excess of test plot
application rates, and metals
concentration in plants is thought to
reach a plateau at higher sludge
application rates.
Another uncertainty in the plant
uptake calculation is the use of a
geometric mean value of all slopes
calculated from individual sludge
studies. If a distribution is lognormal,
the geometric mean provides an
estimate of the median (50th percentile)
slope. Such a value is useful in
estimating uptake for a "typical sludge".
The individual sludge studies that EPA
used to calculate plant uptake used
sludges with higher metals
concentrations than the "typical
sludges" on the market today. Sludges
with higher metals concentration are
most likely to produce higher plant
concentrations. It is possible that the
geometric mean value of uptake slopes
that EPA used is higher than the mean
value would be if the studies used in
calculations were repeated using
currently produced sludge.
Another uncertainty exists as a result
of the way that the geometric mean
calculations were done. A value of 0.001
was used as the uptake slope from
individual studies when there was no
significant increase in metal uptake by
the crops raised on the sludge. A
geometric mean calculation is very
sensitive to the inclusion of low values.
From the inspection of several data sets
it appears that 0.001 is substantially
smaller than the upper bound on uptake
that would be obtained from "no
significant increase in metal uptake"
studies. The use of the default slope of
0.001 may underestimate the typical
slope for crop uptake.
Dietary Consumption
The pollutant limits were calculated
based on population average food
consumption estimates derived in a
study by Pennington. These estimates
are based on United States government
survey data from short term food
consumption reports of large surveyed
populations. Such survey data is an
accepted basis to estimate population
average food consumption rates.
Two limitations exist with the way
that the food consumption estimates
were presented. First, the calculations
presented address the average g/day
food consumption rate. In the sludge
dietary exposure assessment food
consumption values are normalized for
adult body weight. This does not reflect
the higher food consumption rates per
unit body weight of young children
compared with adults. The dietary
assessment does not separately consider
exposures to children as a population
subgroup.
A second limitation of the food
consumption estimates is that they
apply to the United States general
population rather than individuals
raising crops for home consumption. It
is possible that individuals who raise a
particular crop may have a higher
consumption rate than individuals who
only obtain the item from commercial
sources. This would introduce an
underestimation of the consumption
rates in the population considered in
the assessment. On the other hand,
home gardens do not produce year-
round, which may offset this bias.
Fraction of Food Raised on Sludge
Treated Land.
To complete the analysis of the
human food chain pathway it is
necessary to estimate how much food
comes from sludge treated land. USDA
survey data on average percentage food
consumption from home grown crops
was used. While these estimates are
average values for this population, EPA
estimated that large garden plots are
required to produce the amount of home
grown crops assumed in the assessment.
EPA believes that a relatively small
percentage of gardens are that large.
Secondly, because of seasonal factors, it
may be difficult for most gardeners to
produce the quantities of leafy
vegetables that are assumed in the
assessment. Leafy vegetables are
important to the assessment as these
crops tend to have high metal uptake
slopes.
Plant Toxicityand Uptake
The phytotoxicity assessment was
based on the relationships between
sludge application rate and tissue
residue, between tissue residues and
reduction in growth, and between
reduction in growth and reduction in
yield. The relationship between
reduction in growth and reduction in
yield is particularly uncertain. The
uncertainties will vary with chemical,
crop species, and toxic endpoint; the
best data were available for zinc, corn,
and growth reduction. Some crops (e.g.,
beans) and endpoints (e.g.,
reproduction) may be more sensitive to
the effects of sludge, although other
crops (e.g. sudangrass) and endpoints
(e.g., mortality) maybe less sensitive. In
addition, there are limited data about
non-cultivated forest species and
perennials, which may differ in their
response to contaminants.
Phytotoxicity of metals is particularly
sensitive to soil pH and the degree of
binding to the sludge matrix. Most
metals are more bioavailable in acidic
soil, but molybdenum and selenium
may be more available in alkaline soils.
Since forest soils in some areas of the
country may have pH below 5.5, the
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9275
assumption that the analysis represents
a "reasonably worst case" may not
apply to all forest land application.
While some data shows that cadmium
uptake plateaus at a certain
concentration in the soil, other evidence
indicates copper and zinc may continue
to increase. In addition, uptake varies
among plant species; e.g. beets take up
copper more readily than 38 other crops
studied.
However, based upon results from
several field studies, EPA believes that
metals are bound to the sludge matrix
and remain relatively unavailable
biologically.
Wildlife
EPA has no standard methodology for
assessing risks to wildlife. There are
many uncertainties about how sludge
application affects terrestrial wildlife
and soil biota. The analysis presented,
while utilizing available data and
methodologies, only described direct
toxicity to a few species. Uncertainties
exist about how to extrapolate this
information to other birds, mammals,
amphibians, and soil invertebrates
whose relative sensitivity to the
compounds of concern is unknown. The
ecotoxicological analyses focused on
cadmium and lead because the most
data are available for them. Other
chemicals, particularly selenium, may
also be of concern.
The criteria are based on direct
toxicity, and impacts at population and
community levels are not addressed. In
addition, EPA used a simple linear
model of bioaccumulation or
bioconcentration from soil to
earthworms to shrews and did not
model the more complex effects of
sludge contaminants on the terresHal
food chain. The analysis evaluates
effects on shrews as an indicator of
ecotoxicological effects, but there may
be other highly exposed or sensitive
organisms in the forest or field systems.
Other uncertainties arise from the
assumption that 33% of the shrew's diet
consists of contaminated soil biota
(represented solely by earthworms).
Because no standard methodologies
exist, EPA did not consider how sludge
amendment of forest soils or edges of
agricultural fields may change the
composition of species in the plant
community, through either nutrient
enhancement or phytotoxicity. Such
changes, in turn, could change the
species of herbivorous and granivorous
insects, mammals, and birds with
subsequent ramifications throughout the
food web.
Uncertainty also exists about the
impact of sludge on soil biota. The
criteria are based solely on a NOAEL for
the earthworm Eisenia foetida, which
may not be the most sensitive or
appropriate species to evaluate for many
of the chemicals. Additionally, the
analysis did not address the influence
on the soil flora and fauna (nematodes,
protozoa, bacteria, fungi, viruses) of
adding nutrients to the soil or possible
increased exposure to organisms that
feed in the litter layer due to the organic
matter in the sludge.
Aggregate Risk
The statistical approximations tfnd
assumptions used in the aggregate risk
analysis are extensive and several are
important contributors to uncertainty.
While the model used for assessment of
national aggregate risk has not been
validated in comparison to actual
exposure data, the Agency's aggregate
risk assessment models generally reflect
assumptions similar to those described
here.
(1) The assessment assumes that
population exposure is lognormally
distributed before and after exposure to
sludge. As the assessment addresses
many low probability events in the far
tail of the population distribution, a
strict lognormal model may not be
appropriate but no other data were
available.
(2) The effect of sludge use on the
distribution is assessed by making a
small shift to the geometric mean of the
United States population distribution
without changing the geometric
standard deviation. In principle, both
the geometric mean and standard
deviation may be expected to change.
The geometric standard deviation is a
highly sensitive parameter in lognormal
models, so this assumption may be
important in aggregate risk calculations.
(3) For lack of adequate data, the
inherent variability in individual
exposure to pollutants in sludge is not
addressed.
Ground Water
Sensitivity analysis for the ground
water model indicates that numerical
criteria are very sensitive to values
selected for equilibrium partition
coefficients for each pollutant, and the
range of plausible values for these
coefficients spans several orders of
magnitude. However, the Agency
believes that it has chosen reasonable
assumptions for the modeling, resulting
in numerical criteria that are sufficiently
protective of public health.
An additional source of uncertainty
for partition coefficients is the
speciation of metals within soils. For its
calculations, the Agency used single
lumped partition coefficients to
represent the behavior of potential
mixes of metal species within the soil.
These coefficients are based on studies
of sandy loam soils treated with
wastewater sludge and are believed to
provide appropriate and protective
values for the calculations. However, -
under certain local conditions (e.g.,
highly acidic soils), differences in the
speciation of metals could lead to
partitioning that differs by one or more
orders of magnitude from that predicted
by the ground water model. They could
also affect the toxicity of metals in
groundwater.
EPA assumed that sludge would be
uniformly mixed to a depth of 15 cm.
Uneven distribution of contaminants in
soil could lead to "hot spots" and
variation in the amount of leaching to
ground water. However, because the
criteria are based on exposure averaged
over many years of an individual's
lifetime, the Agency believes that this
variation will not significantly affect
total exposure.
Monitoring Study to Address Land
Application Risk Assessment Issues for
Round Two Standards
Section 405 requires EPA to develop
standards for sludge use or disposal
which are adequate to protect public
health and the environment from
reasonably anticipated adverse effects of
pollutants in sludge, present in
concentrations that may adversely affect
public health and the environment. The
statute directs the Agency to promulgate
these standards in two stages and to
revise the standards periodically. The
Agency has concluded that the
standards adopted today are adequately
protective based on its assessment of the
available data. However, to verify its
conclusions about the adequacy of
today's standards, the Agency is
committing to develop a comprehensive
environmental evaluation and
monitoring study. The results of the
study will provide a useful data base for
the Round Two sludge standards. Such
a study will also aid the Agency in its
efforts to develop a comprehensive
ecological risk assessment methodology,
and to correct any uncertainties in
subsequent part 503 rulemakings.
As a minimum this study will
address:
(1) Transport and transformation of
inorganic and organic constituents of
sludge considering leaching, surface
runoff, and soil and sludge binding
capacity (the variability in the binding
capacity of different sludge/soil
matrices will be considered). Ground
water monitoring will be included in
the study to assess whether leaching of
inorganics is occurring;
-------
9276 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(2) Variability of real-world sludge
application practices;
(3) Unavailability of sludge
constituents to both plants and animals
undor different environmental
conditions;
(4) Ecological effects of organic and
inorganic constituents as well as
pathogens, including effects to wildlife
and non-cultivated crops and impacts
on unmanaged plant and animal
communities, endpoints chosen in the
risk assessment for phytotoxicity and
alternative endpoints;
(5) Confirmation of the distribution
and variability in the concentration of
constituents and binding capacity of
sludge matrices; and
(GjLong-term temporal changes; for
example, changes in binding capacity as
sludge ages and sensitivity of the results
to changes in site condition such as
degradation of the sludge matrix, pH
changes, and land-use changes.
EPA will develop a plan for the study
and submit it to external experts for
comment and refinement. The final plan
including study design will be available
for public comment at the time that the
Round Two regulation is proposed. The
Agency is socking comment at this time
on the priority of the various elements
of the study and suggestions for
alternative cost-effective approaches to
address the uncertainties in the human
health and ecological risk assessment.
This information will be used in
development of the study design.
As the Agency develops its ecological
risk assessment methodology and as it
obtains results from the monitoring
study, the risk assessment decisions
made in this final rule may need
revision. The Agency will consider
necessary revisions when the results of
tho monitoring study are available.
The Agency will also further evaluate
the potential risks and benefits of
nutrients contained in sludge in the
Round Two sludge regulations.
Although sludge, like other fertilizers
applied to agricultural land, provides
valuable nutrients needed for crop
growth, over application can degrade
ground and surface water quality. An
extensive evaluation of the effects from
nutrients in sludge was not performed
in Round One. Because sewage sludge
has relatively low nutrient content as
compared to other unregulated
commercial fertilizers, EPA did not
consider nutrients a problem if sewage
sludge is applied at agronomic rates.
Excessive loadings of nutrients from
the use of fertilizers, both organic and
inorganic, pose significant ecological
risks by stimulating the over-enrichment
of estuaries, lakes, reservoirs, bays, and
slower streams in a process known as
eutrophication. Eutrophication occurs
when excess nutrients stimulate the
growth of algae and alter the biological
composition of ecological communities.
In general, nitrogen is the limiting factor
for plant growth in marine ecosystems
and phosphorus is the limiting factor in
fresh water. In some estuarine systems,
both nitrogen and phosphorus can limit
plant growth.
Nitrogen in the form of nitrate is
highly mobile and moves with water. If
nitrate finds its way to ground water
and then to drinking water wells, it may
pose a human health risk. EPA has set
a drinking water standard of 10 mg/1 to
protect against the most sensitive health
effect endpoint, methemoglobinemia
(blue baby syndrome) in infants.
The Agency will consider sludge
management practices in the context of
risks and benefits posed by nutrients in
the Round Two regulations. In addition,
representatives of the U.S. Department
of Agriculture have raised concerns
about the standard for cadmium
contained in these regulations. EPA
believes, based on its current analyses,
that the regulations promulgated today
satisfy the requirements of Section 405
of the Clean Water Act. However, EPA
welcomes additional data and analyses
related to this particular sludge standard
and will consider any such additional
information received by the Agency
within 90 days from the publication of
today's rule. Should significant
additional data or analyses be presented
to the Agency demonstrating that a
different standard is warranted, the
Agency will expeditiously modify this
rule.
Part VII: Risk Management Approach
Agency Risk Management Approach
Armed with the risk characterization
information, the Agency can determine
if a "significant" or "unreasonable" risk
exists, what to do about it or what
controls are necessary, and how to
communicate the risk to the public and
regulated community. Implicit in this
analysis is that the simple identification
of risk is not necessarily sufficient to
justify action. In addition, non-risk
factors such as the availability and-
effectiveness of controls, the existence
of alternatives, and any benefits that
would be lost or gained as a result of
controls must be considered by the
Agency in the process of reaching a
decision. In some cases, the weight of
the risk and benefits will be such that
the benefits outweigh the risks. In such
a case, the Agency's risk management
decision may be to take no regulatory
action. In other cases, risks relative to
benefits are such that the reasonable
action is to reduce the risk or control the
environmental effect.
This process is interactive and affects
earlier components in the risk
assessment. Under each exposure
scenario, the Agency identifies a range
of control strategies and regulatory
requirements that usually reduce
exposure so that the risk or identified
effect is put back into balance with the
benefits. Using the information
provided in the risk management step,
the Agency can select the appropriate
control strategy and means for
communicating it to the public and
regulated community.'
Alternative Regulatory Approaches
Considered in Developing the Final
Rule
Introduction
This part of the preamble discusses
alternatives the Agency considered in
developing today's part 503 rule. EPA
solicited public comments on these
proposed approaches and sought
suggestions for other appropriate
approaches that the Agency could
consider in developing its risk
assessment methodology used to
establish standards for the use and
disposal of sewage sludge. Over the
years, EPA has developed different
regulatory approaches, depending on
the legal requirements of a particular
statute, surrounding issues,
uncertainties, and information bases.
Other EPA statutes covering the same
pollutants or activities have very
different legal requirements from
section 405(d) of the CWA. The
following discussion examines how
different statutes mandate how EPA
establishes standards under different
regulatory regimes.
Title III of the 1990 Clean Air Act
Amendments establishes a program to
reduce emissions of hazardous air
pollutants from stationary sources. Title
III requires EPA to develop standards for
sources of hazardous air emissions
based on maximum achievable control
technology for controlling these
emissions. Section 112 includes a list of
nearly 200 chemicals and chemical
classes for which National Emission
Standards for Hazardous Air Pollutants
may be set. The standards promulgated
under section 112 require the maximum
achievable reduction in emissions,
considering cost and other relevant
factors. Categories and subcategories of
sources are subject to regulation
according to a specified schedule, with
the first set of sources regulated by
1992.
EPA proposed listing sewage sludge
incinerators as a category of major
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9277
sources as required under title in of the
1990 Clean Air Act Amendments (54 FR
28548, June 21,1991). At this time, the
Administrator has decided that listing
this category of sources under the Clean
Air Act is required by the legislation.
Regulatory review of this category will
take into account the final requirements
being promulgated today under part
503. The regulatory review of this
category is not expected to take place for
seven years because comprehensive
controls on this category are in the
incineration subpart of the part 503 rule
being promulgated today.
The EPA may promulgate additional
standards, if needed, to protect health
with an ample margin of safety or to
prevent adverse environmental effects.
Unless new legislation is enacted,
health-based standards will be
mandatory for categories of sources that
pose an estimated cancer risk of greater
than 1x10 ~6 to the most exposed
individual. The schedule for these
"residual risk" standards is nine years
after promulgation of control technology
standards for the first set of source
categories and eight years post-
promulgation for the remaining source
categories.
Under the Safe Drinking Water Act
(SDWA), the Agency first defines a goal
to limit the concentration of the
pollutant in drinking water (maximum
contaminant level, goal—MCLG; for
carcinogens, the concentration goal is
zero). After setting a goal, the Agency
sets an enforceable standard (maximum
contaminant level) based on feasibility.
Under the SDWA, the enforceable
standard may not necessarily achieve
the goal set for the pollutant, but it is
established at a level that is safe for
human health. The Carcinogenic risk
levels for drinking water MCLs
generally range from 1x10 ~6 to 1x10 ~4
The Federal Insecticide, Fungicide,
and Rodenticide Act (FIFRA) and the
Toxic Substances Control Act (TSCA)
explicitly provide for balancing health
and costs in decisionmaking. The
carcinogenic risk levels established
under FIFRA range from lxlO~6 to
1x10 ~4, depending on the type of
exposure involved. Applier exposure is
generally in the range of 1x10 ~4 and
dietary exposure is generally in the
range of IxlO"6. The regulatory limits
under TSCA are driven by balancing
economic analyses and exposure
analyses, with the exposure analyses
also considering adverse health effects
other than carcinogenicity.
Under the Resource Conservation and
Recovery Act (RCRA), Subtitle D (non-
hazardous wastes), the Agency sets
standards to protect human health and
the environment based on the
reasonable probability that municipal
solid waste landfills will cause adverse
effects. The standards are established
considering the "practical capability" of
the facilities. The Agency is requiring
that States establish ground water
protection standard remedies for
carcinogens in the range of 1x10 ~6 to
IxlO"4 (see, 56 FR 50978, October 9,
1991).
However, Subtitle C of RCRA
(hazardous wastes) contains no
provision to consider costs or the
practical capability of a facility to meet
the standards. The standards developed
by the Agency under RCRA Subtitle C
are necessary to protect human health
and the environment. The Agency has
standards that prohibit hazardous waste
incinerator emissions for metals from
exceeding a summed carcinogenic risk
level of 1x10~5.
The Comprehensive Environmental
Response, Compensation, and Liability
Act (CERCLA) directs the Agency to set
standards for cleanup by considering
the relative degree of risk to human
health and the environment. Under
CERCLA, the Agency has set standards
based on carcinogenic risk levels of
1x10 ~7 to IxlO"4, with IxlO"6 as the
departure point for the analysis.
As shown, each statute is unique.
Therefore, the regulatory approach and
limits developed under one statute may
not be appropriate for those developed
under another statute. Before comparing
regulatory requirements, the legal
requirements of the authorizing statute
must be examined.
In developing a regulatory approach,
one of the principles guiding EPA is to
establish reasonable standards. Section
405(d)(2)(D) of the CWA requires the
Agency to establish management
practices and numerical limits that are
"adequate to protect public health and
the environment from any reasonably
anticipated adverse effects of each
pollutant." EPA used exposure
assessment models to derive these
numerical pollutant limits. EPA
determined that the exposure
assessment assumptions used in its
models protect individuals from events
that are likely to occur and meets the
statutory standard to protect public
health and the environment from
"reasonably anticipated adverse effects
of a pollutant."
Selecting a Regulatory Approach for
Part 503
In developing a regulatory approach
for establishing the management
practices and numerical limits
(standards) that would safeguard public
health and the environment, the Agency
examined the use or disposal practices
and the probability that individuals
would be exposed to pollutants from
these practices. EPA identified the type
of the risks involved (e.g., breathing air
with higher levels of pollutants,
drinking water with pollutant levels
exceeding the MCLs for drinking water,
and others). It also examined the
possibility of special populations at
greater risk (e.g., small children playing
in gardens where sewage sludge
products had been applied or the effect
of lead on adult males). The Agency also
examined whether individuals
voluntarily incurred the risks. For
example, risks associated with breathing
more contaminated air by individuals
living in close proximity to an
incinerator are involuntarily incurred
and, therefore, more unacceptable than
risks associated with using a properly
labeled sewage sludge product in a
garden. Finally, before developing
alternative approaches, EPA used
exposure assessment models to project
the effect on an individual receiving a
maximum dose throughout an average
lifespan of 70 years. Aggregate effects
analyses were used to project the
incidence of adverse health effects from
sewage sludge use or disposal on the
population as a whole (i.e., the resulting
number of cancer cases, carcinogenic
risk, number of people exposed to lead
at levels producing adverse health
effects, and the number of people
exposed to concentrations of non-
carcinogenic pollutants above a
reference dose—RfD).
In considering a regulatory approach,
in the proposal EPA primarily focused
on two types of risks—risks to
individuals receiving the maximum
dose (most exposed individual, plant or
animal—MEI) and risks to the
population as a whole (aggregate risk).
The Agency considered four regulatory
approaches for the use and disposal of
sewage sludge. Each of the approaches
places greater emphasis on reducing an
individual or other organism's exposure
to a pollutant. However, the Agency
examined both the individual and
aggregate effect of each alternative to
balance the uncertainties in the
analyses. The data available resulted in
greater emphasis being placed on public
health rather than environmental
effects. However, where environmental
effects could be identified, even
qualitatively, they were considered in
the determination of what constituted
"adequate" protection of public health
and the environment.
Opinions are divided concerning the
emphasis that should be placed on
individual or aggregate risk. There are
some who maintain that individual
cancer risk is the most, or the only,
-------
9278 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
important measure. Arguments that
favor addressing individual risk assert
that no individual should be at high risk
and that consideration of the number of
people at risk leads to acceptance of
higher individual risk when few people
are exposed. Furthermore, the latter
approach leads to the inequity of having
the acceptable risk to an individual
depend on the number of people
similarly exposed. The limitation of
using maximum individual risk alone is
that the measure does not indicate how
many people may be affected. It only
relates the carcinogenic risk to the MEL
Arguments in favor of examining the
aggregate risk are that incidence is an
appropriate measure of total public
health impact. Therefore, incidence is a
good indicator of whether an approach
adequately protects public health.
A rule mat covers Doth carcinogenic
and non-carcinogenic pollutants, such
as today's rule, presents another
disadvantage to using only an MEI or an
aggregate analysis as a single measure of
whether an approach adequately
protects public health and the
environment. Methodologies and data
do not yet exist, except for lead, to
correlate differing levels of exposure to
non-carcinogenic pollutants with
incidence of an effect. The only measure
for threshold pollutants other than lead
is the number of people exposed to a
level above a RfD. This, in fact, may
have little meaning for individual risk
since risk above the RfD cannot be
determined using the RfD methodology.
The RfD is established such that there
is a very low probability that exposure
to a pollutant at or below the RfD will
cause an individual health case. This
also implies that there is no certainty
that exposure above the RfD will cause
an individual health case. Therefore,
while any exposure to carcinogens can
bo considered a case, the same
assumption can not be made for non-
carcinogens.
In addition, the Agency typically
weighs the aggregate effects estimates
along with maximum individual or
average cancer risk estimates when
evaluating a particular category of like
risks (i.e., the number of individuals
exposed to a particular pollutant from a
particular type of facility). Some
observers question the relevance of
adding risks, in a rule such as today's
rule, when risks from different types of
pollutants present different types of
risks (i.e., inhalation, ingestion, and
others) from different types of sources
(i.e., incineration, land application for
agricultural purposes, among others).
The following discussion describes
the proposed alternative regulatory
approaches considered by the Agency in
developing the risk assessment
methodology used in today's rule. The
first two approaches accept the
aggregate effects of current sewage
sludge quality. Approach HI is directed
solely to protecting the MEI and
Approach IV uses a combination of MEI
exposure and aggregate effects of current
sewage sludge quality.
Although the combination of
approaches in Option IV was the
Agency's selection for purposes of the
part 503 proposal, it was revised for the
final rule based on current Agency
policy, public comment and scientific
peer review.
Approach I: Use Existing Regulations
(Aggregate Approach)
The first approach considered by the
Agency was to use existing regulations
to establish numerical limits and
management practices. In establishing
numerical limits for sewage sludge that
is incinerated, the Agency would use
the NESHAPs for mercury and
beryllium in 40 CFR part 61, subparts C
and E, respectively; 25 percent of the
NAAQSs for lead; and the particulate
limitations and monitoring
requirements in 40 CFR part 60, subpart
O. In addition, the Agency would have
also used numerical limits for cadmium
and PCBs and the pathogen reduction
process requirements in 40 CFR part 257
when sewage sludge is applied to the
land. Under this approach, if existing
regulations did not address a particular
pollutant, EPA would have used the
toxicity characteristic pollutant
concentrations in 40 CFR part 261 to
determine if a sewage sludge was
hazardous. Therefore, standards for
hazardous sewage sludge would not be
established in part 503. All approaches
considered by the Agency similarly
exclude hazardous sewage sludge from
the part 503 standards. As discussed
later in the preamble, for purposes of
section 405, EPA is regulating
hazardous sewage sludge under the
requirements in 40 CFR parts 261
through 268 and sewage sludge with 50
ppm or more PCBs under the
requirements in 40 CFR part 761.
The first approach was rejected
immediately by the Agency because it
would misuse the toxicity characteristic
concentrations. The toxicity
characteristic concentrations were
developed to identify pollutant
concentrations in wastes that, if placed
in improperly managed MSWLFs have
the potential to cause an unacceptably
high level of ground water
contamination. The regulatory
thresholds do not purport to define a
concentration that would be safe if used
for growing food or feed crops. The
toxicity characteristic concentrations, if
used in the exposure assessment
models, would result in concentrations
exceeding the human health criteria for
the disposal practice. Limiting emission
levels of sewage sludge incinerators to
25 percent of the NAAQS for lead
would require some incinerators to
install wet electrostatic precipitators
(ESPs). At present, many States are not
controlling lead emissions from sewage
sludge incinerators.
Approach II: Use the 98th-Percentile
Pollutant Concentration (Aggregate
Approach)
The second approach considered by
the Agency was to use existing EPA
regulations, as in the first approach.
However, if existing regulations do not
establish numerical limits, numerical
limits would be established
corresponding to the 98th-percentile
pollutant concentration in the Agency's
national data base on sewage sludge.
The 98th-percentile pollutant
concentrations would be calculated
from a regression analysis of the values
of each pollutant in the national data
base and would be used as a cap on
allowable pollutant concentrations. This
would preclude potential deviations
from the pollutant concentrations
shown in the national data base and
prevent increases in any risks associated
with current use and disposal practices.
In addition to management practices
specified in existing regulations, such as
pathogen reduction processes for the
land application of sewage sludge in 40
CFR part 257, the Agency would require
that labels or information sheets
accompany sewage sludge products that
are distributed and marketed. These
would inform users about the proper
use of the product.
Approach III: Use the Exposure
Assessment Models for All Practices
(MEI Approach)
The third approach that the Agency
considered was to use the exposure
assessment models in establishing
numerical limits for all use or disposal
practices. The exposure assessment
models allow the Agency to limit not
only the concentration of a pollutant in
sewage sludge, but also the annual and
cumulative loading rates for pollutants
when sewage sludge is applied to land
used for growing food-chain crops or
distributed and marketed.
In the MEI approach, the target
organism is a most exposed individual,
plant, or animal that remains for an
extended period of time at or adjacent
to the site where the maximum
exposure occurs. EPA used models and
14 exposure pathways to determine the
-------
Federal Register / Vol, 58, No, 32 / Friday, February 19, 1993 / Rules and Regulations 9279
concentration of sludge-borne pollutants
that may be utilized or disposed of in
each use and disposal practice without
exceeding human health or
environmental criteria.
The human health and the
environmental criteria used to protect
the MEI from the adverse effects of
specific pollutants were taken from
criteria already published or
promulgated by the Agency, from
human health criteria developed by the
Agency, or from plant and animal
toxicity values published in scientific
literature. For example, when the
objective was to protect sources of
drinking water, pollutant limits were
developed which would ensure the
Agency's maximum contaminant levels
were not violated. When the objective
was to protect surface water, Water
Quality Criteria were used. If the
Agency had not published or
promulgated criteria for specific
pollutants, reference doses listed in the
Agency's computerized Integrated Risk
Information System were used.
For carcinogens, the risk-specific
doses corresponding to an incremental
carcinogenic risk level of 1x10~5 were
used for all use and disposal practices
except when sewage sludge was
distributed and marketed. For the
distribution and marketing of sewage
sludge, numerical limits were
established to ensure pollutant levels do
not exceed a risk-specific concentration
corresponding to an incremental
carcinogenic risk level of lxlO~6.
For all pathways, the human MEIs
were assumed to be the most sensitive
individuals continuously exposed over
a 70-year lifetime. Ecological MEI
endpoints were also conservatively
constructed, using the most sensitive
species with steady-state duration and
concentration of exposure over a critical
life period.
Approach IV: Use the Exposure
Assessment Models and the 98th-
Percentile Pollutant Concentration (The
Approach Used in the Part 503
Proposal)
The final approach that the Agency
considered, and the one on which the
Agency based the part 503 proposal,
used a combination of aggregate and
MEI analyses (i.e., the second and third
approaches). The Agency used existing
regulations, the NESHAPs for mercury
and beryllium and 25 percent of the
NAAQS for lead when sewage sludge is
incinerated. EPA also used the exposure
assessment models to establish
numerical limits, as in the third
approach, when individuals are likely to
be exposed to high levels of pollutants
in sewage sludge or when significant
scientific uncertainties exist about the
effect of a particular sewage sludge use
or disposal practice.
However in this approach, the Agency
selected an incremental carcinogenic
risk target of lxlO~4 for sewage sludge
used in the production of agricultural
crops, the sale or give-away of sewage
sludge products, and the disposal of
sewage sludge in monofills. This target
was selected because Agency analyses
did not indicate a significant aggregate
populational carcinogenic risk for these
practices. The Agency's analyses did
indicate, however, that incineration
posed significantly more aggregate
populational carcinogenic risk than
other use or disposal methods. To
reduce this aggregate carcinogenic risk,
the Agency proposed regulating the
incineration of sewage sludge such that
the carcinogens in the emissions would
not exceed an incremental unit risk of
lxlO~5.
The Agency did consider an
incremental carcinogenic risk level of
lxlO~6 for all practices. This option
was rejected because EPA's analyses
indicated that such an approach may
lead to the incineration of greater
volumes of sewage sludge with a
potential for increased human health
risks. Furthermore, considerable
uncertainty remained in projecting the
number of cancer cases. Since the
number was already small (for other
than incineration), increased
uncertainty exists in projecting further
reductions.
Carcinogenic risk targets were applied
pollutant-by-pollutant in all use or
disposal practices, except for the
organic pollutants in the emissions of
sewage sludge incinerators. For
incinerators, the Agency set a limit on
the total hydrocarbon emissions from a
sewage sludge incinerator rather than on
each individual organic pollutant. To do
this, the Agency developed a weighted
average risk-specific concentration for
the carcinogenic organic compounds
listed in IRIS. The Agency believed that
this was comparable to setting a
pollutant-by-pollutant risk-specific
concentration for the metals in
incinerator emissions.
When individuals were unlikely to be
exposed to the pollutants in sewage
sludge, the Agency proposed setting
numerical limits that correspond to the
98th-percentile pollutant concentration
in the Agency's national data base on
sewage sludge. As in the second
approach, the 98th-percentile
concentration is a cap on the allowable
concentration of a pollutant in sewage
sludge that precludes significant
deviations from the concentrations
shown in the national data base to avoid
increased risk from the disposal of
sewage sludge.
The 98th-percentile pollutant
concentration applied to the application
of sewage sludge to land used for non-
agricultural purposes (i.e., forests,
reclaiming lands, and others), a practice
on which human dietary impacts are
negligible. The 98th-percentile pollutant
concentration also applied to the
disposal of sewage sludge on surface
disposal sites, which are generally
small, located away from population
centers, and usually located on property
owned by the treatment work. The
Agency believed that little, if any,
likelihood of exposure to the pollutants
from these two use and disposal
methods would result.
Comments on the Alternative
Regulatory Approaches
The Agency received extensive
scientific peer review and public
comments on the proposed alternative
regulatory approaches. These comments
focused on the MEI exposure scenario
used to determine human health
impacts and on the use of the 98th-
percentile technique for deriving
numerical pollutant limits for sewage
sludge. A description of the
commenters' major concerns is
presented below.
The Most Exposed Individual Approach
The risk and exposure assessment
assumptions and data used in the model
pathways for the MEI approach were
criticized by many commenters as being
inappropriate or too conservative to
mirror "real world" situations'. For
example, many commenters took issue
with the Agency's exposure assessment
scenario posing an MEI who lives near
a sewage sludge disposal site and is
exposed continuously (i.e., 24 hours per
day) for a 70-year lifetime—used to
establish numerical pollutant
concentrations in sewage sludge that
protect public health. Commenters
maintained that such exposures were
unrealistic and should be considerably
less than 70 years, and that few
individuals would be expected to live in
the same location for their entire lives.
Commenters suggested that the Agency
revise the MEI exposure assessment
assumptions to reflect more realistic
exposure conditions.
Commenters were divided on which
risk levels should be used by the
Agency to protect the MEI. As discussed
earlier, the Agency traditionally
establishes standards within a range of
1x10 ~7 to 1x10 ~4, depending on the
statute, surrounding issues,
uncertainties, and information bases.
Many commenters argued that the risk
-------
9280 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
lovols selected by the Agency (i.e.,
1x10 "•* for all use and disposal
practices, except lxlO~5 for
Incineration) were too conservative,
while other commenters felt that the
Agency was not stringent enough and
should lower the risk level to the
lxlO~*to lxlO~7 range. Some
commontors maintained that the same
risk level should be used for all use and
disposal practices, and that the different
risk levels (i.e., 10 ~4 vs. 10 ~s) used in
the proposal were not scientifically
justifiable, do not reflect an ample
"margin of safety," and fail to consider
non-carcinogenic effects. Other
commenters suggested that the risk for
all regulated pollutants destined for
incineration (i.e., four metals and total
hydrocarbons) be additive to allow
facilities the flexibility to trade off their
emissions and still meet an overall
additive risk level for the five pollutants
of SxlO"5. Still other commenters were
supportive of the proposal, stating that
the risk levels selected by the Agency to
protect the MEI were appropriate for the
use and disposal practices regulated and
thai no change was needed.
Even though many commenters were
critical of the risk policy decisions and
exposure assessment assumptions and
data (e.g., duration of exposure, use of
salt/pot studies, soil ingestion rates, and
others) used by the Agency in the MEI
approach, none of the commenters
suggested an alternative regulatory
approach that they believed would be
more scientifically defensible and
provide an adequate level of protection
of public health and the environment.
The QBlh-Percentile Approach
Many commenters were critical of the
98th-percentile approach stating that the
approach had scientific and technical
deficiencies and either over or under
regulated the use and disposal of sewage
slndgo, depending on the pollutants of
concern and the practice. Further, the
commontors maintained that the
numerical limits derived from the 98th-
porcentilo approach were not supported
by adequate risk assessments and were
not substantiated by field studies. These
limits could not be considered a
substitute for plant and animal exposure
pathway analysis and subsequent
calculation of numerical limitations by
consideration of the pathway analysis.
In addition, may commenters felt that
the 98th-percentile approach would
reduce the desirability of beneficial use
practices because of the increased
public perception of a human health or
environmental risk. Some commenters
suggested that all beneficial use
practices should be consistent and use
the same risk assessment methodology.
Response to Comments
The Agency agrees with many of the
comments provided by the public and
scientific peer review committees
concerning the risk assessment
approach used to develop numerical
limitations for the part 503 proposal.
The proposed approach (a combination
of MEI and 98th-percentile approaches)
was necessarily constrained by the
adequacy of information and data on the
fate, transport and effects of sewage
sludge pollutants, parameters and
assumptions used in the model
pathways and exposure assessment
analyses, and on the use and disposal
practices.
Furthermore, there is no clear
guidance in section 405, which provides
only that standards must be adequate to
protect public health and the
environment against reasonably
anticipated adverse effects. There is
only limited discussion of how to
establish pollutant limits under section
405(d) of the Clean Water Act in the
legislative history of the Act (U.S.
Congress, Senate, Senator Stafford, 16
October 1986, Congressional Record
S16427). Senator Stafford in debate on
the legislation stated:
* * * EPA's rules must also establish
numerical limitations for each such
pollutant. EPA's rules must protect public
health and the environment with an ample
margin of safety, and must take care to
protect the health of individuals or
populations which are at higher risk than the
population as a whole.
EPA concluded that its statutory duty
to protect against reasonably anticipated
adverse effects required it to consider
reasonable risks to exposed populations
and not the risk associated with highly
unlikely or unusual circumstances.
Accordingly, the Agency decided to
evaluate the risk to a highly exposed
individual (HEI), instead of the most
exposed individual (MEI), for the final
part 503 regulation risk assessment.
This more realistically reflects
protection of the health of individuals
or populations which are at higher risk
than the population as a whole.
EPA also decided to retain a 70 year
exposure for the HEI in the risk
assessment for the final part 503
regulation. The Agency recognizes that
the exposure assessment assumption of
70 years of continuous exposure is
conservative in the context of a highly
mobile society. Further, EPA is aware
that the assumption constitutes a
simplification of actual conditions. The
decision to assume 70-year exposure for
standards setting purposes represents,
in part, a policy judgment by EPA. EPA
believes this assumption is preferable to
the less conservative alternatives
suggested. Although releases of
pollutants from sewage sludge use and
disposal practices would reasonably be
expected to change over time, such
changes cannot be predicted with any
degree of certainty. In lieu of
discontinuing a practice, facilities may
elect to replace or even expand their use
or disposal practice and subsequently
increase their release of pollutants to the
environment. The 70-year exposure
duration represents a steady-state
exposure assessment assumption that is
consistent with the way in which the
measure of carcinogenic risk is
expressed (i.e., as the probability of
contracting cancer based upon a lifetime
[70 year] exposure to a unit
concentration). Constraining the
analysis to an "average" lifetime
exposure carries the implication that no
one could be exposed for a period
longer than the average. Since, by
definition, approximately half the
population would be expected to be
exposed longer than the average, this
assumption would tend to
underestimate the possible risk to
highly exposed individuals and
populations.
The Agency agrees that the U.S.
population, in general, is highly mobile.
However, adjusting the exposure
assumptions to constrain the possibility
of exposure to pollutant releases from
sewage sludge use and disposal
practices implies that everyone has the
same degree of mobility (e.g., children,
the elderly and handicapped) and that
exposure during the periods away from
the residence are zero. EPA knows this
is not the case. In addition, a less-than-
lifetime exposure assumption would
also have a proportional impact on the
estimated risk to highly exposed
individuals, suggesting that no
individual could be exposed for 70
years. On balance, EPA believes that the
present exposure assessment
assumption of continuous exposure is
consistent with (1) the steady-state
nature of the analysis and with (2) the
stated purpose of providing an adequate
level of public health and
environmental protection from any
reasonably anticipated adverse effects of
pollutants found in sewage sludge. In
the Agency's opinion, this exposure
assessment assumption, while
representing in part a policy judgment
by EPA, continues to be preferable to
the less conservative alternatives
suggested and represents an appropriate
one, given the Agency's obligation to
protect public health. This is true both
in view of the shortcomings of such
alternatives and in the absence of
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9281
compelling evidence to the contrary.
Further, retaining 70-year assumption
gives EPA confidence that the
population of highly exposed
individuals will remain extremely
small.
To remedy information gaps in
preparing the MEI risk assessment
analyses for the part 503 proposal, the
Agency used what it believed were
"reasonable worst-case" assumptions.
Each parameter or assumption has a
"margin of safety" associated with it,
depending on the accuracy of the data
and information supporting it. For
example, if the Agency lacked data from
sludge/field studies on metals uptake in
crops grown for human consumption,
data from sludge/pot studies or salt/pot
studies was used in the MEI risk
assessment analysis. The margin of
safety associated with the data from
salt/pot studies is greater than the
margin of safety associated with data
from sludge/pot studies and far greater
than the margin of safety associated
with data from sludge/field studies.
However, given the availability of the
data at the time of proposal, the Agency
believed that the use of data from salt/
pot studies in the absence of data from
sludge/pot or sludge/field studies was a
reasonable worst-case assumption and
provided an adequate level of public
health and environmental protection.
The problem occurs when a series of
parameters and assumptions, each
having a large margin of safety, are used
in the same exposure pathway
assessment. This results in an extremely
conservative analysis where the margin
of safety for each parameter and
assumption has a compounding effect
resulting in numerical limitations that
appear to be unrealistic and could
conceivably over-regulate a use and
disposal practice.
A number of commenters supported
the Agency's policy decision on setting
the acceptable risk level to the MEI at
1x10 ~4 for all use and disposal
practices except incineration, which
was set at 1x10 ~5. The Agency disagrees
with commenters who proposed that the
risk levels selected by the Agency may
not be stringent enough, may be too
conservative, or may lead to an
inconsistent policy allowing different
acceptable risk decisions for different
use and disposal practices. For the final
part 503 regulations, EPA established
standards after an evaluation of risks at
the same risk levels as those used for the
proposed rule. Based on this evaluation,
which included new information
gathered during and after the public
comment period for the proposal, the
Agency concluded that the risk levels
selected for the proposal were protective
of public health, and that different
human health effects levels (i.e., the
different human health effects for
incineration vs. other use and disposal
practices) could appropriately result in
different acceptable risk decisions but
that the proposed risk level for
incineration was unnecessarily
protective and burdensome.
Information provided by the NSSS,
the sludge incinerator study, the
scientific peer review committees and
the public was incorporated into the
aggregate risk assessment for the final
rule and showed minimal risk from
current sludge management methods
(referred to as "pre-Part 503" or
"baseline" risk). Sludge incineration,
which EPA had believed based on its
earlier analysis posed the greatest risk to
the widest population, exhibited low
baseline risk. Consequently, the Agency
decided to evaluate standards for the
final part 503 rule that would achieve
an HEI risk level no higher than 1x10~4
for all use and disposal practices. The
Agency disagrees with commenters that
argued that our assumptions in
describing and protecting the HEI are
not conservative enough. For example,
in the incineration pathway scenario the
Agency assumed that the HEI was
exposed to incinerator emissions 24
hours a day for 70 years, and that the
HEI was physically located where it
would receive the highest annual
ground level concentration of pollutant
emissions for the entire exposure
period. The aggregate risk assessment,
which included the effects on highly
exposed individuals and
subpopulations (HEIs) as well as the
population as a whole, was based on
many conservative exposure
assumptions such as these, and verified
that the lxlO~4 risk level provided an
adequate level of public health
protection across all use and disposal
practices including incineration. In
addition to providing an adequate level
of public health and environmental
protection, the 1x10 ~4 risk level
reduces the regulatory impact of the rule
allowing the Agency to regulate the use
and disposal of sewage sludge without
needlessly burdening the regulated
community or negatively impacting
beneficial reuse.
In addition, the Agency disagrees that
the risk levels for pollutants in sewage
sludge that is incinerated should be
additive to allow facilities the flexibility
to trade-off emissions to meet a higher
risk level (e.g., adding a 1x10~4 risk
level for each of four carcinogenic
metals and total hydrocarbons to
establish a higher risk level for
compliance of 5x10 ~4). The Agency
evaluated the potential for the summed
risk of pollutants in sewage sludge to
exceed the proposed risk level. Sewage
sludge from 30 facilities was evaluated
to determine if the total carcinogen risk
of the pollutant mixture exceeded the
carcinogen risk from the single highest
risk pollutant found in the mixture. In
all but three cases, a single pollutant
dominated the risk. Therefore, the
Agency believes that summing the risk
would not make a significant difference
in complying with the final Part 503
rule regardless of the risk level chosen.
Neither does the Agency believe that it
would justify the increased
administrative burden it would impose
on regulatory authorities and permit
writers who would need to constantly
readjust permits to account for varying
mixtures of pollutant concentrations
and for new pollutants regulated under
future rulemakings.
The Agency agrees with the public
and the scientific peer review
committees that the 98th-percentile
approach is inconsistent with the MEI
approach and that numerical limitations
derived from the 98th-percentile
approach do not ensure protection of
public health and the'environment
because they lack a formal pathway risk
assessment.
In preparing the part 503 proposal,
the Agency relied on the 98th-percentile
approach because it did not have
reliable exposure assessment models
nor the input data and information
needed to conduct a formal pathway
risk assessment for certain practices.
The Agency believed at the time of the
proposal that the 98th-percentile
approach would adequately protect
public health and the environment
because the 98th-percentile pollutant
limitations would apply to: (1) The
application of sewage sludge to land
used for non-agricultural purposes (i.e.,
forests, reclaimed lands, and others), a
practice on which human dietary
impacts are negligible and other forms
of human and environmental exposure
appeared to be low; and (2) the disposal
of sewage sludge on surface disposal
sites, which are generally small, located
away from populated centers and
usually located on property owned by
the treatment works, and therefore
should present little, if any, likelihood
of exposure. In addition, the 98th-
percentile approach was supported by
the Agency's aggregate risk assessment
which showed low exposure and
minimal human health impacts on the
population as a whole from these use
and disposal practices. This information
further supported the Agency's belief
that the 98th-percentile approach was
protective of public health and the
-------
9282 Federal Register / Vol.-58, No. 32 / Friday, February ,19, 1993 / Rules and Regulations
environment and acceptable for
purposes of proposal.
Since the proposal, the Agency has
worked with experts from inside and
outside EPA to develop, then refine, the
modeling techniques and supporting
data to conduct a formal pathway risk
assessment for these practices. In
addition, the public comments and
scientific peer review reports have
provided EPA with better data and
information that improved the precision
and accuracy of certain modeling
parameters and assumptions used in the
risk assessment to derive numerical
limitations for all sewage sludge use and
disposal practices. This allowed EPA to
establish more realistic numerical
limitations without compromising the
level of protection of public health and
tho environment.
Final Action—Risk Assessment
Methodology for the Part 503 Rule
Based on public comments, scientific
poor review and the record developed in
tho rulomaking, EPA has selected an
approach based on risk to highly
exposed individuals (HEIs) and
consideration of health protection for
higher risk populations (aggregate risk
assessment), not an unrealistic worst-
case ME! approach. The Agency has
decided to use a risk assessment*
methodology consistent with EPA
guidelines and based on (or supported
by—in the case of the operational
standard for sludge incineration) an
exposure pathway assessment using an
array of assumptions and modeling
parameters some of which are worst-
case and others that are more reasonably
based. EPA believes that this approach
Is consistent with the Congressional
intent to establish standards "adequate
to protect public health and the
environment from reasonably
anticipated adverse effects of each
pollutant."
Thus, EPA evaluated the risk to
highly exposed individuals and
populations from pollutants found in
sovvago sludge using different exposure
assessment pathways The aggregate risk
assessment (which assessed risk to the
HEI as well as the population as a
whole) showed minimal risk from the
use and disposal of sewage sludge under
current (pre-part 503) sludge
management methods. Therefore, the
Agency concluded that if the standards
developed under the final part 503
regulations protect the HEI to a cancer
rlsK level no higher than IxlO"4 for all
sewage sludge use and disposal
practices, that risk level is considered
an adequate level of public health
protection.
Further, EPA also evaluated as part of
its risk assessment (also using exposure
assessment pathways), bther non-
carcinogenic health risks and
environmental effects,from pollutants
found in sewage sludge! The risk level
of 1x10 ~4 established by the Agency for
this rule provided a benchmark for
judging the level of protection to the '
HEI and populations at greater risk from
carcinogenic pollutants, but did not
constitute a rigid line for making'the
determination that such risk is adequate
to protect public health and the
environment from "all reasonably
anticipated adverse effects." The
Agency recognized early on that
consideration of non-cancer risk.to
individuals and other environmental
effects were critical in .evaluating the
protectiveness of standards promulgated
in today's rule. . -.' . ,
As a result, in evaluating standards
for today's final rule that provide an
adequate level of protection of public ,
health and the environment, the Agency
set standards not only based on cancer
risk but on a series of other health and
environmental effects. These include
the overall incidence of other serious
health effects as well as cancer within
the exposed population as a whole
(including average exposed and highly
exposed individuals) and within special
subpopulations, such as children. The
Agency also considered effects on plants
and animals from exposure to pollutants
found in sewage sludge, science, policy
assumptions, estimation of uncertainties
and margin of safety associated with the
risk assessment parameters and
assumptions, weight of the.scientific ,'
evidence for human .health and
environmental effects, other quantified
or unquantified health and
environmental effects, and other
impacts associated with the use and
disposal of sewage sludge before
selecting the final standards.
Section 405 of the CWA requires EPA
to develop regulations for sewage
sludge, when used or disposed of, that
are protective of public health and the
environment, hi today's action, the
Agency has selected an HEI approach
with consideration of the health effects
on higher risk individuals and ,.
subpopulations and the population as a
whole (aggregate risk assessment) to
establish numerical pollutant
limitations, operational standards and
management practices for the use and
disposal of sewage sludge. The Agency
has concluded that the numerical
pollutant limitations, operational
standards and management practices
will provide an adequate level of '
protection of public health and the
environment from any reasonably
anticipated adverse effects of the
pollutants found in sewage sludge.
As noted above, EPA employed
exposure assessment models to develop
risk-based numerical pollutant limits for
sewage sludge when it is applied to the
land or placed on a surface disposal site.
EPA has determined that its statutory
duty to ensure adequate protection of
public health and the environment
requires the Agency to add safety factors
to the numerical criteria derived from
the exposure assessments.
The decision to include additional
safety factors in its protective numerical
pollutant limitations serves a second
critical objective in this rulemaking.
That objective is to promote the use of
sewage sludge for its beneficial
properties. An important component in
promoting the beneficial use of sludge is
building public confidence that sewage
sludge used to grow the food the public
eats is safe. Adding a margin of safety
to the model-derived criteria should
help courage this.
There are two reasons for adding
safety factors to the model-derived
numerical criteria.
First, designing these models has
required EPA to make a number of
assumptions to characterize the
exposure to an HEI. Given current
modeling tools, in developing the
Agency's exposure assessments, it
Would have been impossible to account
for all of the variables in the real-world
movement of pollutants from sewage
sludge to environmental end points.
EPA, as a consequence, made a number
of assumptions to reduce the complexity
of actual experience. EPA is confident
that its exposure assessments (and the
resulting risk-derived numerical
limitations) generate numerical criteria
consistent with protection of public
health and the environment. At the
same time, EPA recognizes that
modelling is not an exact science. Of
necessity, there are aspects of its
exposure assessment about which the
Agency has greater confidence and areas
in which, because of data limitations or
because the analytical tools are not
highly developed, less certainty.
Second, through its exposure
assessments, EPA derived numerical
limitations for metals that represented
the total quantity of metals that could be
added to the soil. So long as the total
quantity (loading) for the metal is not
exceeded, the exposure assessment
models predict that there will be no
injury to the HEI. The model is
unconcerned whether the total quantity
of the pollutant is received in a single
load or over time. Thus, adopting purely
a cumulative loading approach could
mean that sewage sludge with extremely
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9283
high, metals concentrations could be
applied to the land so long as the
cumulative load is not exceeded.
In developing the final numerical
pollutant limitations, the Agency
concluded that adoption of a strictly
risk-based numerical pollutant
limitation may allow degradation of
current sewage sludge quality. EPA's
aggregate risk assessment shows only
small public health effects associated
with current use and disposal practices.
This confirms what EPA's exhaustive
review of data on sludge usage revealed,
that is, sludge used at current pollutant
concentration levels presents a low risk
to public health and that such pollutant
levels already have an inherent level of
protection. However, its exposure
assessment models relied, in part, on
data from field studies on sewage sludge
applied to agricultural land that
represented a range of sewage sludge of
different concentrations. The models do
not look exclusively at data from the
most heavily contaminated sludges or
consider ecological systems impacts
from sludges applied to non-agricultural
lands.
In order to ensure continued
protection of public health and the
environment, EPA concluded that
existing quality of sewage sludge that is
applied to land should be "protected".
and not allowed to deteriorate above
current concentration levels. Implicit in
EPA's numerical pollutant limits for
land application (and its conclusion that
such limits are safe) is the assumption
that sludge with low concentrations of,
pollutants is safe and to downgrade the
quality of sludge reduces the protective
levels inherent in such limits. In these
circumstances, EPA has concluded that
its certainty about the protectiveness of
the numerical criteria derived from its
exposure assessment models for land
application is increased by adding
margins of safety to the numerical ,
criteria.
Accordingly, the Agency has placed a
"ceiling" on the concentration of
pollutants in sewage sludge that may be
applied to land at the 99th-percentile
pollutant concentration from the NSSS
survey. The ceiling concentration is the
higher of the 99th-percentile pollutant
concentration or risk-based pollutant
limitation and acts as a trigger, dictating
when sludge quality is no longer
suitable for beneficial use (regardless
how it is applied to the land) and must
be disposed of. An important purpose of
the "ceiling" is to direct the "cleanest"
sludges into beneficial use practices,
thereby preventing the "dirtiest"
sludges from being applied to
agricultural land under the veil of
beneficial use. In addition, the Agency
has "capped" the numerical pollutant
limits for land application at the 99th-
percentile pollutant concentration'
found in the NSSS if that concentration
is lower than the risk-based numerical
pollutant limit. The "cap" determines
when sludge quality is suitable for
beneficial use under the alternative
pollutant limit concept or must be
applied using cumulative pollutant
loading rates (alternative pollutant
limits and cumulative pollutant loading
rates are discussed below in parts VIII
andXI). :
The Agency has made these risk
policy decisions (i.e., the "capping and
ceiling" policies) to provide an
additional margin of safety to protect
public health and the environment
beyond the risk-based standards
developed for today's rule, while
maintaining sewage sludge quality to
encourage sludge utilization consistent
with the Agency's beneficial use policy.
In today's action, the Agency has
selected an HEI approach with
consideration of the health effects on
higher risk individuals and
subpopulations and the population as a
whole (aggregate risk assessment) to
establish numerical pollutant
limitations, operational standards and
management practices for the use and
disposal of sewage sludge. It is the
Agency's belief that the numerical
pollutant limitations, operational,
standards and management practices
will provide an adequate' level of
protection of public health and the
environment from any reasonably
anticipated adverse effects of the :
pollutants found in sewage sludge. The
following p'aft, part VIII, describes the
exposure assessment methodology for
each sewage sludge use and disposal
practice that was an outgrowth of the
public comments and scientific peer
review on the proposed regulatory
approach.
Part VIII: Exposure Assessment
Methodology and Other Risk
Management Issues for Sewage Sludge
Use and Disposal Practices for the Final
Rule
This part of today's preamble
discusses how EPA evaluated exposure
and assessed the risk in determining
what pollutant limits in the final part
503 rule were needed to protect public
health and the environment from
pollutants in'sewage sludge that is
applied to the land, placed on a surface
disposal site, or fired in a sewage sludge
incinerator. Included in this part is a
discussion of the exppsure assessment
approach used to develop pollutant
limits in both the proposed and final
part 503 rule, as well as a discussion of
the basis of other technical and non-
technical assumptions used in the
regulations.
Exposure Assessment Methodology and
Risk Management Issues for the
Proposed Rule
For the proposed rule, EPA adapted
existing models and developed new
models to determine the concentration
of sewage sludge-borne pollutants that
may be applied to the land, placed in
sewage sludge-only landfills (monofills),
or incinerated without exceeding
human health or environmental criteria
(Reference Nos. 71, 72, and 79). The
models simulate the movement of
pollutants into and through the
environment with a series of
mathematical equations or algorithms.
These equations or algorithms link the
pollutant disposal or release rates to the
concentration of the pollutant that
moves into the air, water, or land and,
subsequently, reaches a target organism
(i.e., plants, animals, and humans). Each
algorithm in a model represents one
exposure pathway through which
sewage sludge-borne pollutants enter
and pass through or effect an
environmental medium.
The exposure pathways modeled for
each use and disposal practice in the
part 503 proposal were as follows:
1. Land Application to Agricultural Land
Sludge-soil-plant-human (Pathway 1)
Sludge-soil-plant-human-future use change
(Pathway IF)
Sludge-soil-human-future use change
(Pathway 2F)
Sludge-soil-plant-animal-human (Pathway
3)
Sludge-soil-animal-human (Pathway 4)
Sludge-soil-plant-animal toxicity (Pathway
5)
Sludge-soil-animal toxicity (Pathway 6)
Sludge-soil-plant toxicity (Pathway 7)
Sludge-soil-soil biota toxicity (Pathway 8)
Sludge-soil-soil biota-predator of soil biota
toxicity (Pathway 9)
Sludge-soil-airborne dust-human (Pathway
10)
Sludge-soil-surface water-contaminated
water-toxicity to fish-toxicity to humans
(Pathway 11)
Sludge-soil-air-human (Pathway 12 A)
Sludge-soil-ground water-human (Pathway
12W)
2. Distribution and Marketing
Pathway IF, 2F, 7, 8, 9, and 11
3. Land Application to Non-Agricultural
Land
Pathway 11 and 12W
4. Monofilling
Pathway 12A and 12W
5. Surface Disposal
Pathway 12A and 12W
6. Incineration
Inhalation of incineration participates by
humans (Pathway 12A)
Both current and future exposures
were considered with respect to
-------
9284 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
conversion of agricultural lands to home
gardens (Pathways IF and 2F). Future
conversions of non-agricultural lands to
either agricultural lands or home
gardens were considered by imposing a
5-yoar waiting period. However, growth
of practices to accommodate future
increases in sludge volume or shifting
between practices were not considered
in establishing the numerical limits.
For all these pathways, the target
organism was the most exposed
individual, plant, or animal that
remained for an extended period of time
at or adjacent to the site where the
maximum exposure occurred. The
models calculate individual pollutant
exposure, relying on certain fixed
assumptions about the exposure route.
For example, the models assumed
inhalation of 20 cubic meters of air per
day—an individual diet representative
of extreme upper-end food
consumption—and consumption of two
liters of drinking water per day. Other
assumptions included in the models
were mo location of the MEI relative to
the site where the sewage sludge is
placed and the source of food in the diet
of the MEI. The same duration of
exposure was used as that assumed in
developing the applicable human health
or environmental toxicological criteria
(allowable doses). For example, where
cancer risks were evaluated, the MEI
was assumed to be continuously
exposed for 70 years. Ecological MEIs
were also conservatively constructed,
using the most sensitive species with
steady-state duration and concentration
of exposure.
The Agency selected numerical values
for the parameters in the algorithms of
cadi model, translated the models into
computer programs, and where
appropriate, used the models to
calculate the numerical limits in the
proposal. The numerical limits derived
from the exposure assessment models
and pathways were based on human
health or environmental criteria already
published or promulgated by the
Agency, on human health criteria
developed by the Agency, or on plant
and animal toxicity values published in
the scientific literature. The numerical
pollutant limits were designed to
protect a most exposed individual (MEI)
for a lifetime of exposure (except the
pathway that addresses exposure of a
child) to a pollutant in sewage sludge
that is used or disposed. The dose that
the ME! could receive for the exposure
was the dose allowed by established
Agency health criteria (e.g., an RfD for
inorganic pollutants for a person who
consumes plants grown on sewage
sludge-amended soils or a threshold
toxic soil concentration for an animal
that grazes on sewage sludge-amended
soils). Use of these values protects the
MEI against the reasonably anticipated
effect of a pollutant (e.g., in the case of
the cadmium RfD, this represents a level
in the human renal cortex not associated
with significant proteinuria).
The risk level for the carcinogenic
pollutants controlled in the proposed
part 503 regulation varied by use or
disposal practice. When sewage sludge
is incinerated, the numerical limits for
beryllium and mercury were based on
the NESHAPs for these pollutants, and
the numerical limit for lead was based
on the NAAQS for lead. When the
objective was to protect sources of
drinking water, pollutant limits were
developed which would ensure the
MCLs were not violated. When the
objective was to protect surface water,
EPA Water Quality Criteria were used.
If the Agency had not published or
promulgated criteria for specific
pollutants in the proposal, EPA used
reference doses listed in IRIS and risk-
specific doses corresponding to an
incremental carcinogenic risk level of
1x10 ~4, except when sewage sludge was
incinerated. For the incineration of
sewage sludge, numerical limits were
established to ensure pollutant levels
did not exceed a risk-specific
concentration corresponding to an
incremental carcinogenic risk level of
lxlO~5. Terrestrial criteria designed to
protect plants or animals were based on
toxicity values determined from the
appropriate scientific literature.
A complete description of the
exposure assessment methodology and
risk management issues for the proposal
is found at 54 FR 5764-5791. The
following sections discuss the exposure
assessment pathways modeled in the
final part 503 rule, the major comments
received on the proposed exposure
assessment approach and risk
management issues, the critical
modifications and risk management
decisions made in developing the final
exposure assessment approach for each
sewage sludge use and disposal
practice. A detailed discussion of the
exposure assessment methodology (i.e.,
models, pathways, parameter values,
assumptions, and others) and the risk
management decisions used to develop
numerical limitations for the final part
503 rule can be found in the technical
support documents for each sewage
sludge use and disposal practice.
Information on obtaining these
documents is provided in Part XIV—
Availability of Technical Informational
on the Final Rule.
Exposure Assessment Pathways and
Risk Management Issues Evaluated for
the Final Part 503 Rule
EPA evaluated 14 pathways of
potential exposure to pollutants in
sewage sludge for the final part 503 rule.
The rule distinguishes between sewage
sludge that is applied to the land for a
beneficial purpose and sludge disposed
of on the land. For the final regulation,
EPA looked at potential exposure when
sludge is used as a fertilizer or soil
conditioner under two generic
categories: agricultural land and non-
agricultural land. Agricultural land
application would include use by a
farmer to grow food or feed crops, on
pasture and rangeland, use by large agri-
business enterprises as well as use by
the home gardener. Home garden use
was formerly described as "distribution
and marketing" but for the final rule is
"sewage sludge sold or given away in a
bag or container." Non-agricultural uses
include use on forest land, reclamation
sites and public contact sites. In the case
of agricultural land, EPA evaluated 14
pathways of exposure, for non-
agricultural land, 12 of the applicable
14. EPA evaluated 2 pathways of
exposure for surface disposal sites. This
is the descriptive term the rule uses for
sludge that is merely disposed on land
either in piles or in sludge-only landfills
(also referred to as monofills). For
sewage sludge that is incinerated, EPA
evaluated a single pathway of
exposure—inhalation. Below are the 14
exposure assessment pathways
evaluated in the final part 503 rule,
followed by a brief description of each
pathway:
1. Land Application (Beneficial Use)
Sludge-soil-plant-human (Pathway 1)
Sludge-soil-plant-home gardener (Pathway
2)
Sludge-soil-child (Pathway 3)
Sludge-soil-plant-animal-human (Pathway
4)
Sludge-soil-animal-human (Pathway 5)
Sludge-soil-plant-animal toxicity (Pathway
6)
Sludge-soil-animal toxicity (Pathway 7)
Sludge-soil-plant toxicity (Pathway 8)
Sludge-soil-soil biota toxicity (Pathway 9)
Sludge-soil-soil biota-predator of soil biota
toxicity (Pathway 10)
Sludge-soil-airborne dust-human (Pathway
11)
Sludge-soil-surface water-contaminated
water-fish toxicity- human toxicity
(Pathway 12)
Sludge-soil-air-human (Pathway 13)
Sludge-soil-ground water-human (Pathway
14)
2. Surface Disposal
Sludge-soil-air-human (Pathway 13)
Sludge-soil-ground water-human (Pathway
14)
3. Incineration
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9285
Sludge-incineration particulate-air-human
(Pathway 13)
In situations where the Agency
determined that the exposure
assessment pathways analyzed for a
particular use or disposal practice did
not yield adequately protective results,
additional management practices were
imposed to prevent environmental
abuses and to protect public health.
For the assessment, all pathways,
except Pathways 3, 5, and 7), assumed
the mixing of sewage sludge with 15
centimeters (i.e., 6-inch plow depth) of
the surface soil layer (having a mass of
2 million kilograms per hectare) either
by mechanical incorporation or by
weathering processes. This allowed
conversions between pollutant
concentrations in soil (in mass of
pollutant per unit mass of soil), and
cumulative pollutant loading rates for
metals (in mass of pollutant per hectare
of land) and annual pollutant loading
rates for organics (in mass of pollutant
per hectare of land per 365-day period).
After first determining the pollutant
concentration in the soil that would be
allowed (i.e., the maximum pollutant
concentration in the soil that, when
taken up by a plant and consumed by
a target organism, does not produce
undue risk) for a particular pathway, the
model determines the allowable
pollutant loading rate in one of two
ways. For metals, the model determines
the cumulative pollutant loading rate,
the total quantity of metal consistent
with no undue risk. This equals the
allowable pollutant concentration in the
soil multiplied by the mass of the soil
in the top 15 centimeters of a hectare of
land. The Agency assumed that metals
remain in the sludge-soil matrix and
that, over time, they become less
biologically available to plants.
For organic pollutants, the model
determines an annual pollutant loading
rate (in kilograms per hectare per 365-
day period) by considering the rate of
pollutant loss or decay. The model
assumes first order decay of organic
pollutants; that is, the quantity of an
organic pollutant lost per year is
directly proportional to the quantity
present. With continual annual
applications, the concentration of a
pollutant gradually approaches a
plateau at which the quantity lost each
year equals the quantity applied. The
annual pollutant loading rate is
determined such that the concentration
levels off at the allowable soil
concentration when sewage sludge is
applied over a long period of time.
For all human exposure pathways in
the final rule, the maximum allowable
intake of pollutants was based on the
following EPA health effects criteria: A
reference dose (RfD), recommended
daily allowance (RDA) or concentration
(RfC) for non-carcinogens; a risk-specific
dose for carcinogens based on a risk
level of 1x10 ~4 for all use and disposal
practices; a daily dietary intake derived
from a drinking water standard; or a
drinking water standard (MCL). The
only exception to this is the dust
inhalation pathway (Pathway il).
In Pathway 11, the pollutant
concentration in the soil is not
permitted to exceed the National
Institute of Occupational Safety and
Health (NIOSH) workplace air quality
criteria if significant quantities of soil
become airborne. Assuming that the
total airborne dust does not exceed the
NIOSH criterion, this pathway was not
a limiting pathway for any pollutant in
the final rule.
Currently, 100 percent of a Maximum
Contaminate Level (MCL) or other
health-based standard is used as the
reference point in developing numerical
pollutant limits in the final part 503
rule. Because the numerical pollutant
limits are based on assumptions
designed to be protective of highly
exposed individuals and the final part
503 regulations control sludge quality
before it is used or disposed of, the
Agency did not believe that MCLs or
other health-based standards used in the
exposure pathway assessment required
any additional margin of safety beyond
the margin of safety provided by
parameters used in the pathway to
protect against reasonably anticipated
worst-case conditions. However, EPA's
1991 Ground Water Protection Strategy
emphasizes prevention and recognizes
that reaching an MCL or other health-
based standard in ground water that is
currently or reasonably expected to be
used as a drinking water source is a
failure of policy. Using a percentage of
the MCL or health-based standard (e.g.,
50 percent) as the reference point
provides a margin of safety that makes
the reference point consistent with the
prevention policy in the 1991 Ground
Water Protection Strategy (i.e., MCL is
not reached).
With the publication of the final part
503 regulation, the Agency is soliciting
public comment on the use of a
percentage of the reference point (i.e.,
an MCL or other health-based standard)
to develop the allowable concentration
of pollutants in sewage sludge for the
ground water pathway in both the land
application and surface disposal risk
assessments. EPA is requesting public
comments within 90 days of the date of
publication of the final part 503
regulation on the use of a percentage of
the MCL or other health-based standard
as the reference point for the ground
water pathway in the land application
risk assessment. The Agency will
consider the public comments in future
amendments to part 503 for the ground
water pathwaj.
The following is a brief summary of
each of the pathways analyzed for the
final part 503 rule. As discussed
previously, a more detailed description
of the pathways and the entire risk/
exposure assessment methodology can
be found in the technical support
documents for the rule.
Pathway 1
This pathway evaluates human
exposure to crops grown with sludge
fertilizer. It is designed to protect
consumers who eat produce grown in
soil using sewage sludge. The
environmental endpoint is an HEI
assumed to live in a region where a
relatively high percentage of the
available cropland receives sewage
sludge applications. All crops in the
diet could be presumed to be affected.
However, it is assumed that the HEI
ingests a mix of crops from land on
which sewage sludge was applied and
from land on which sewage sludge was
not applied. For this pathway, 2.5
percent of a consumer's intake of grains,
vegetables, potatoes, legumes, and
garden fruits is assumed to be grown on
sludge-enriched soil.
Pathway 1 evaluates crops grown for
human consumption when sewage
sludge is applied. Uptake of sewage
sludge pollutants is assumed to occur
through the plant roots. Direct
adherence of sewage sludge or soil to
crop surfaces is assumed to be minimal,
and crops are assumed to be washed
before consumption. The relevant
practices for this pathway include
agricultural use in commercial
enterprises where crops for human
consumption are raised, whether in pots
(e.g., hothouse production) or in the
field (e.g., truck farming).
The exposure evaluated for Pathway 1
in a non-agricultural setting is the
exposure of a person who ingests wild
berries and mushrooms grown in
sludge-amended soils. The exposure to
a pollutant in sewage sludge in Pathway
1 is based on (1) the uptake of a
pollutant by each type of wild berry and
mushroom; (2) a daily consumption of
wild berries and mushrooms; and (3) the
fraction of different wild berries and
mushrooms grown in sewage sludge-
amended soil. The HEI for Pathway 1 is
a person who lives in a region where
sewage sludge is applied to forest, a
public contact site, or a reclamation site.
The dose for this pathway is the RfD for
an inorganic pollutant. Organic
-------
9286
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
pollutants were not evaluated for this
pathway because they do not
concentrate in wild berries and
mushrooms.
Pathway 2
This pathway evaluates the case in
which sludge is added to the soil in a
homo garden. The major difference
between Pathways 1 and 2 is the
fraction of food groups produced on
sewage sludge-amended soil. For this
pathway, as much as 60 percent of the
HEI's diet of certain food groups is
assumed to be grown in the home
garden in which sludge is used as
fertilizer.
The HEI for Pathway 2 is the home
gardener who produces and consumes
potatoes, leafy vegetables, legume
vegetables, root vegetables, and garden
fruits. These are also consumed, but not
produced, by the HEI in Pathway 1.
Unlike the HEI in Pathway 1, grains and
cereals and peanuts are not included in
the crops grown and consumed by the
HEI in Pathway 2 because home
gardeners do not usually consume
grains and cereals and peanuts they
grow themselves on sewage sludge-
amended soils. For these individuals,
the percentage of their diet grown on
sewage sludge-amended soil is the
percentage of their diet that is
homegrown.
PatiiwayS
This pathway assesses the hazard to a
child ingesting undiluted sewage
sludge. The HEI is the child who ingests
sewage sludge from storage piles or from
the soil surface. It is assumed that the
sewage sludge is not diluted with soil
when exposure occurs. The sewage
sludge incestion rate used was 0.2 grams
(dry weight) per day for 5 years based
on the 1989 Agency soil ingestion
directive suggesting this value for
children at higher risk (U.S. EPA, 1989).
For this rule, EPA assumed ingestion at
this level would be limited to 5 years.
In Pathway 3, EPA used the integrated
uptake biokinetic model (IUBK) instead
of extrapolating from cattle data, as had
boon done earlier for the proposal, to
evaluate the effects from lead on
children ingesting sewage sludge. The
IUBK model used a lead blood level not
to exceed 10 micrograms per deciliter, a
30 percent absorption value and a 95th-
porconUle population distribution to
protect the HEI. Using these values in
the model results in an allowable
sewage sludge lead concentration of 500
parts per million (ppm) generated by the
IUBK model. The lead pollutant limit
calculated by the Peer Review
Committee was based on the
observation that body burdens
(absorption) of animals fed up to 10
percent of their diet as sewage sludge
did not change until the lead
concentration in the sewage sludge
exceeded 300 ppm. The Agency,
therefore, decided to select the more
conservative numerical limit for the
final part 503 rule to minimize lead
exposure to children and set the
allowable lead concentration in sewage
sludge at 300 ppm for this pathway.
Several reasons support this
determination. First, setting the
allowable lead concentration at 300
ppm provides an additional margin of
safety with respect to lead soil
contamination and any threat to the
systems of developing children. Because
childhood ingestion of dirt is so
widespread a phenomenon and the
potential consequence so severe, a high
order of conservatism is warranted on
this point, especially in the context of
regulatory decisions authorizing the
addition of a threshold pollutant like
lead to the environment. In addition, a
300 ppm lead concentration in sludge is
consistent with current sewage sludge
quality at all but a small number of
POTWs. As a result, the societal cost of
an additional safety factor is small in
comparison to the potential benefits.
Pathway 4
The analysis developed for this
pathway is designed to evaluate human
exposure from the consumption of
animal products. Pollutant limits
calculated for this pathway protect a
highly exposed human being consuming
the tissue of foraging animals that have
consumed feed crops or vegetation
grown on sewage sludge-amended soils.
The HEI is assumed to consume daily
quantities of the various animal tissue
food groups. The HEI is also assumed to
be exposed to a background intake of a
pollutant.
Animals may consume forage and
grain produced on sewage sludge-
amended soil. This pathway depends on
plant uptake of a contaminant being
proportional to soil concentration of the
contaminant. Uptake can occur through
the roots with transport to shoots or
other edible feedstuffs, or by
volatilization from soil to above ground
parts of plants.
The allowable pollutant concentration
in the soil is the quotient of the
allowable pollutant concentration in the
feed crop and a crop uptake factor
(partition coefficient). The allowable
pollutant concentration in the feed crop
is determined from: (1) the human
intake of pollutant that can be allowed
without causing undue risk, (2) typical
consumption rates of various classes of
animal products, (3) the percentage of
each class of animal product assumed to
be raised on sludge-amended soil, and
(4) a set of uptake factors relating the
pollutant concentration in each animal
product to the pollutant concentration
in the feed consumed by the animal.
Forty percent of the HEI's diet of meat,
dairy products and eggs is assumed to
come from animals consuming feed
from soil to which sludge was applied.
This is especially warranted in the
context of regulatory decisions
involving the addition of threshold
pollutants to the environment.
For Pathway 4 in a non-agricultural
setting, a human consumes meat or
products from wild animals that
consume plants grown in sewage
sludge-amended soil. The meat is
assumed to be obtained from hunting
wild animals (herbivores) that forage
vegetation grown in sewage sludge-
amended soil on forest and reclamation
sites. The allowable dose for this
pathway is the RfD for an inorganic
pollutant adjusted for a 70 kilogram
person minus the background
contribution of the pollutant from air,
water, and food. The exposure for this
pathway is based on (1) uptake factors
relating the pollutant concentration in
each animal product to the pollutant
concentration in the plant consumed by
the wild animal, (2) typical
consumption rates of various classes of
animal products, and (3) the percentage
of each class of animal product assumed
to forage on sludge-amended soil.
Pathway 5
This pathway involves the application
of sewage sludge to the land, the direct
ingestion of this sewage sludge by
animals, and finally, the consumption of
contaminated animal tissue by humans.
The analysis developed for this pathway
evaluated pollutant loading limits to
protect a highly exposed human
consuming the tissue of foraging
animals that have incidentally ingested
sewage sludge. The HEI is assumed to
consume daily quantities of the various
animal-tissue food groups as determined
by an EPA analysis of the diet. The HEI
is also assumed to be exposed to a
background intake of pollutant.
A grazing animal can be exposed to
direct ingestion of sewage sludge by two
quite different methods. The first
involves direct ingestion of sewage
sludge by livestock, where sewage
sludge has been surface-applied to
pasture crops. Livestock can ingest
sewage sludge adhering to the crops or
lying on the soil surface. Each year the
grazing livestock are presumed to be
exposed to freshly applied sewage
sludge with no time for dissipation of
the organic pollutants. Alternatively,
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9287
sewage sludge can be injected into the
soil or mixed with the plow-layer soil,
and the grazing livestock ingest the soil
sewage sludge mixture. Livestock
exposure will obviously be maximized
when sewage sludge is directly ingested,
and hence this ingestion route is
considered in this analysis.
It is assumed that only a small
percentage of the grazing livestock's diet
is sewage sludge, and that not all of the
animal tissue consumed by the HEI is
derived from livestock that have been
feeding on sewage sludge-amended
land. Background pollutant intake by
the HEI (i.e., the ingestion of pollutants
from all sources other than that
associated with the application of
sewage sludge to the land) is taken into
consideration through data derived by
EPA for total background intake.
Path way 6
This pathway evaluates what level of
pollutants in sludge is protective of
animals that ingest plants grown on
sewage sludge-amended soil. Pathway 6
is designed to assist in setting pollutant
loading limits that protect the highly
sensitive/highly exposed herbivorous
livestock that consumes plants grown
on sewage sludge-amended soil. It is
assumed that the livestock diet consists
of 100 percent forage grown on sewage
sludge-amended land and that the
animal is exposed to a background
pollutant intake. In this pathway,
different animals are affected by
different pollutants; thus, when a
sensitive species has been identified for
a pollutant, that species is used in the
exposure assessment. Among the
species looked at for this pathway were
livestock, domestic grazing animals,
birds and rodents although not all were
reviewed for each pollutant,
Pathway 7
This pathway is designed to evaluate
pollutant loading limits that are
associated with protection of the highly
sensitive/highly exposed herbivorous
livestock, which incidentally consumes
sewage sludge adhering to forage crops
and/or sewage sludge on the soil
surface. It is assumed that the percent of
sewage sludge in the livestock diet is 1.5
percent and that the animal is exposed
to a background pollutant intake. Again,
different animals are considered in this
pathway when evaluating the different
pollutants; thus, when a sensitive
species has been identified for a
pollutant, that species is used in the
exposure assessment.
Pathways
This pathway evaluates the risk posed
by pollutants in sludge to plant growth.
For the plant toxicity pathway, the
Agency determined an allowable
pollutant concentration in the soil that
would be associated with a low •
probability (1x10 ~4) of a 50 percent
reduction in young plant growth. This
value was derived from scientific data
relating the growth of young plants and
soil contaminant levels. Thus, the
allowable pollutant load for this
pathway is that load which, after
dilution with 15 centimeters of soil,
does not exceed the threshold value.
The Agency has determined that the
relationship between reduction in
growth and reduction in yield is
particularly uncertain for metals such as
chromium. Phytotoxicity resulting from
metals is sensitive to changes in soil pH,
plant species and to the degree of
metals' binding in the sludge matrix.
Based on data provided during the
public comment period, EPA concluded
that metals remain bound in the sludge
matrix and are relatively unavailable
biologically. However, the Agency
determined that its data base on soil
types and plant species sensitivity was
limited and that pollutants regulated by
this pathway should be "capped" (as
discussed earlier) at the 99th-percentile
pollutant concentration from the NSSS
to provide an additional margin of
safety to protect sensitive plant species
not fully evaluated in its risk
assessment.
Pathway 9
The analysis developed for this
pathway is designed to assist in setting
pollutant loading limits that protect the
highly exposed/highly sensitive soil
biota. At this time, limited sludge field
data exists that indicate the level at
which inorganic pollutants become
toxic to soil biota. However, Hartenstein
et al. (1980) routinely raised earthworms
using sewage sludges, which provided a
limited source of data. Evidence does
not prove that they are highly sensitive
species; however, because of the lack of
data for other species, the criteria for
this pathway have been set using
earthworm data. The criteria are based
on a No Observed Adverse Effect Level
(NOAEL) for the earthworm Eisenia
foetida.
Pathway 10
The analysis developed for Pathway
10 is designed to assist in setting
pollutant loading limits that protect
highly sensitive/highly exposed soil
biota predators. Of concern in this
pathway, therefore, are sensitive
wildlife that consume soil biota that
have been feeding on sewage sludge-
amended soil. No predator has been
singled out as being particularly
sensitive to cadmium and lead, but
rather the literature has been reviewed
to identify what the Agency determined
is a pollutant intake level protective of
sensitive species in general. This is not
the case for PCBs, where clear evidence
exists that chickens are a highly
sensitive species. Chronic exposure
assumes that 33 percent of the sensitive
species' diet is soil biota.
Pathway 11
This pathway evaluates human
exposure to sludge pollutants through
inhalation. The HEI for this pathway is
the tractor driver tilling the field. This
pathway evaluates the impact of
particles that have been resuspended by
the tilling of dewatered sewage sludge.
The particles are inhaled by a tractor
operator.
This pathway assumes that the
distance from the driver to the soil
surface is one meter, sewage sludge is
incorporated to a depth of 15
centimeters, and sewage sludge and soil
are well mixed. This HEI is not expected
to be exposed to more than 10
milligrams per cubic meter (g/m3) of
total dust. At dust levels at or above this
level, the American Conference of
Governmental Industrial Hygienists
(ACGIH) recommends that individuals
work within a closed cab.
Pathway 12
The surface run-off pathway, Pathway
12, is intended to protect beneficial use
of surface waters in order to protect
human health and aquatic life. This
pathway evaluates the risk to surface
water associated with run-off of
pollutants from soil on which sludge
has been applied. The exposure
assessment calculates the pollutant
concentration in sludge-amended soil
that would not result in exceeding a
Water Quality Criterion for a pollutant
if the soil enters a relatively small
stream. The rate at which the soil enters
the stream was based on the Universal
Soil Loss Equation and a sediment
delivery ratio. Water Quality Criteria are
designed to protect human health,
assuming exposure through
consumption of drinking water and
resident fish, and to protect aquatic life.
Pathway 13 (Land Application)
In model Pathway 13 for land
application practices, the Agency
evaluated the exposure of members of a
farm household inhaling vapors of any
volatile pollutants that may be in the
sewage sludge when it is applied to the
land. This pathway was considered for
six pollutants: benzo(a)pyrene, bis(2-
ethylhexyljphthalate, chlordane, DDT,
dimethylnitrosamine, and
-------
9288 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
polychlorinatod biphenyls. These
pollutants were originally selected by
the Agency as pollutants of concern
from the hazard indices screen because
of their semi-volatile nature. The
Agency did not evaluate the vapor
pathway for organic pollutants like
benzene, Undone, trichloroethylene, or
toxaphono because these pollutants,
which are highly volatile, would
volatilize in wastewater treatment
processes before sewage sludge
disposal—either during wastewater
aeration or during sludge processing
and dowatering—and thus were not
considered to be of concern. In addition,
non-volatile metals were not evaluated
in the vapor pathway.
The vapor pathway assumes that the
total amount of pollutant spread in each
year would vaporize during that year.
Thus, tho allowable annual pollutant
loading rate is equal to the flux (mass of
pollutant per unit area per unit time)
that may be allowed to enter the
atmosphere without exceeding the
allowable pollutant concentration in the
air. This concentration corresponds to
tho RfC, risk-specific dose, or an
acceptable daily dose derived from an
MCL. A plume model was used to relate
tho flux to the resulting pollutant
concentration in the air. The allowable
flux is determined by: (1) the allowable
pollutant concentration in the air, (2)
tho size of the sewage sludge
application site, (3) the assumed
distance of an individual from the site
whore tho air concentration must be
attained, (4) the wind speed; and (5) the
dogrco of atmospheric mixing. The wind
direction is assumed never to change, so
tho HEI always remains in the center
Hno of the plume.
Patliway 13 (Surface Disposal)
In exposure Pathway 13 for surface
disposal sites, the Agency evaluated the
exposure of an individual inhaling
vapors of any volatile pollutants that
may bo in the sewage sludge disposed
at a surface disposal site. The individual
(HEI) is assumed to be living at the
downwind edge of the site and is
inhaling air, at a rate of 20 cubic meters
por day for 70 years, that has been
contaminated with volatile organic
compounds from sewage sludge
disposed of at the site.
volatilization rate coefficients for
uncovered cells are calculated with
equations that consider constituent
parameters including the Henry's Law
coefficient, molecular weight and
distribution coefficient. The rate of
contaminant release through
volatilization is estimated separately for
a covered site. Contaminant loss to the
vapor pathway is diluted into the total
volume of air passing within two meters
over the site during the period of
contaminant release. This box model is
used to determine the expected air
concentrations to which the HEI is
exposed for each unit of concentration
vaporized at the downwind edge of the
site. The allowable lifetime exposure to
each contaminant (based on a risk level
of lxlO~4) is then used to back-
calculate the allowable loss rate to the
vapor pathway. This value is then
divided by the fraction of contaminant
vaporized to determine the allowable
pollutant concentration at the site.
Pathway 13 (Incineration)
In model pathway 13 for incineration,
the Agency evaluated the exposure of an
individual living in close proximity to
a sewage sludge incinerator. This
individual is assumed to inhale
particulates and gases from the
incinerator 24 hours per day, 365 days
per year for 70 years. This highly
exposed individual is located at a point
where the highest annual ground level
concentration of incinerator emissions
occurs. This pathway was evaluated for
five heavy metals: arsenic, cadmium,
chromium, lead and nickel and
approximately 70 organics which are
represented by a surrogate measure of
total hydrocarbons.
Risk-specific concentrations of the
four carcinogenic metals are established
from cancer potency values found in
IRIS. An acceptable ground level
concentration of lead is established at
10 percent of the NAAQS for lead.
Allowable stack emission rates for these
five heavy metals are calculated by use
of site-specific air dispersion models.
Allowable concentrations of the five
heavy metals in sewage sludge are
calculated by determining the metal
removal efficiency across the incinerator
and air pollution control device site-
specifically and considering the whole
sludge feed rate to the incinerator.
Pathway 14 (Land Application)
In this pathway, the Agency evaluated
the exposure of individuals who would
obtain their drinking water from ground
water located directly below a field to
which sewage sludge had been applied.
The leachate concentration formed in
the sewage sludge-amended soil layer is
related by a partition coefficient to the
pollutant concentration in the soil. In
moving down through the unsaturated
zone, the peak leachate concentration is
reduced by the modeled processes of
vertical dispersion (primarily caused by
detention of sorbed pollutant), chemical
degradation, and metal precipitation.
The allowable pollutant loading rate
was thus determined from the MCL that
must be met at the ground water
interface with no allowance for dilution,
the rate of decay of a pollutant, and
other factors that affect either the time
period for decay or the dispersive
smoothing of the peak concentration.
These other factors include the recharge
or infiltration rate, hydraulic
characteristics of the soil, depth to
ground water, and the chemical
partition coefficient. For some metals,
the net ground water electromotive
potential (Eh) and ground water pH
influence metallic species precipitation
out of aqueous solution.
Pathway 14 (Surface Disposal)
In exposure Pathway 14 for surface
disposal sites, the Agency evaluated the
exposure of individuals who would
obtain their drinking water from ground
water contaminated by the surface
disposal site. Exposure concentrations
are predicted based on well locations
150 meters or less downgradient of the
site for facilities located over a source of
drinking water. Reference drinking
water criteria are either MCLs or are
based on a risk level of 1x10~4 for an
HEI who consumes two liters of water
per day over a 70-year lifetime.
Numerical pollutant limits for the
ground water pathway are derived for
both covered (sludge-only landfills—
monofills) and uncovered surface
disposal sites. Pollutant losses are first
partitioned among the three competing
loss processes: Volatilization, leaching
to ground water, and on-site
contaminant degradation. For surface
disposal sites other than monofills, the
relatively high water content of the
sewage sludge received at the site
results in an increased rate of seepage
from the facility as compared to that
estimated for monofills. Once the
fraction of contaminant lost to leaching
has been determined, a module is used
to estimate flow and transport through
the unsaturated zone and is linked to a
three dimensional analytical model to
depict fate and transport in the
saturated zone. The linked model
considers the extent to which
constituent transport in the saturated
zone if affected by local mounding of
the water table beneath the site. The
module accounts for a number of
processes including advection,
dispersion, adsorption, and degradation.
The mass flux into the saturated zone is
used as input to the model which
couples this source term with aquifer
characteristics to predict concentrations.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9289
Comments on the Proposed Exposure
Assessment Approach and Risk
Management Issues for Land
Application Practices
Land Application—Agricultural
Practices
As a result of public comments and
scientific peer review, many of the
assumptions and data used in the
exposure assessment methodology to
generate numerical limitations for the
proposed rule have been changed to
reflect more up-to-date information and
more realistic exposure scenarios
describing the expected conditions on
which sewage sludge will be land-
applied for agricultural purposes. The
following is a discussion of the major
comments, responses and actions taken
by the Agency in developing the final
part 503 regulations for agricultural land
application of sewage sludge. A
complete discussion of all the
comments and the Agency's responses
can be found in the Response to
Comments Document for the Proposed
Part 503 Rule (Reference No. 109). In
addition, a more detailed explanation of
the Agency's scientific approach can be
found in the Technical Support
Document for Land Application.
Information on obtaining single
copies of these documents can be found
in Part XIV—Availability of Technical
Information on the Final Rule.
1. Reconstructing Proposed Pathways 11
and 12
Comment: Many commenters
suggested that EPA completely
reconstruct the surface run-off
(proposed Pathway 11), vapor (proposed
Pathway 12A), and ground water
(proposed Pathway 12W) exposure
pathways for agricultural land
application practices. They
recommended that EPA incorporate
better fate and transport models and
different modeling assumptions into the
exposure assessment (e.g., some
commenters criticized the Universal
Soil Loss Equation model used in
Pathway 11 as too simplistic). In
addition, commenters argued (1) that
100 percent of a constituent cannot be
available both to volatilize from the site
and simultaneously to leach into ground
water and (2) that a mass balance
methodology should be used to account
for partitioning of pollutants across
multiple pathways.
Eesponse: The Agency agrees that
proposed Pathways 11,12A, and 12W
(Pathways 12,13, and 14 in the final
rule) should be revised to make use of
improved models and more realistic
modeling assumptions and that a mass
balance methodology should be used to
account for partitioning of pollutants
across these pathways. EPA has made
numerous revisions to its exposure
assessment pathway models for the final
rule. The previous section (Exposure
Assessment Approach for the Final Part
503 Rule) briefly summarizes exposure
pathways 12,13, and 14 as well as the
other 11 pathways used in the final rule
to calculate numerical limits for sewage
sludge applied to agricultural land.
The land application exposure
assessment is complex and made up of
a large number of pathways and
parameters. At the time of proposal, the
Agency realized that the models used in
assessing the risks in developing the
proposed limits for the land application
of sewage sludge involved a number of
uncertainties and technical issues.
Consequently, the proposal identified
many of these issues and asked for
comment. However, in the absence of
data or compelling evidence to the
contrary, the Agency selected the
models and parameters, and constructed
the pathways in the proposal to ensure
protection of public health and the
environment from pollutants found in
sewage sludge applied to agricultural
land. Based on information and data
gathered during the public comment
period, the Agency determined that
many of the assumptions used in the
exposure pathways for the proposal
were overconservative, resulting in
numerical pollutant limits with an
unnecessarily high margin of safety.
Final Action: Exposure pathways 11,
12A and 12W were revised (Pathways
12,13, and 14 in the final rule) and EPA
developed a new methodology that
accounts for the partitioning of
pollutants between these pathways in
response to scientific peer review and
public comments. To partition
contaminant losses among competing
processes, all losses are treated as first-
order, and a rate-loss coefficient is
calculated for each. The first-order loss
rate, the decay or degradation rate for a
pollutant, is proportional to the
concentration of the pollutant at any
point in time. The higher the
concentration of the pollutant, the
greater the rate of loss. A first-order rate
loss coefficient is calculated for each
competing environmental process; soil
erosion, leaching to ground water and
for volatile pollutants, vaporization.
Using the rate-loss coefficient a fraction
of pollutant lost to each pathway is then
determined.
For the land application exposure
assessment, EPA partitioned pollutants
based on the rate of leaching to ground
water, volatilization to air, erosion to
surface water, pollutant decay and
retention on the land surface. The
Agency did not include plant uptake in
the mass balance equations since much
of the contaminant taken up by plants
is not actually removed from the site
and may therefore remain available for
leaching, erosion or volatilization. The
reconstructed pathways for land
application practices follow (These
pathways also have been reconstructed
and the mass balance methodology
applied to non-agricultural land
application and to surface disposal
practices):
Pathway 12—Criteria for the surface
water erosion pathway are determined
based on the fraction of contaminant
lost to surface waters, the dilution of
sewage sludge-amended soil with soil
from the rest of the watershed,
partitioning between the aqueous and
adsorbed phases in the stream, and the
bioconcentration of the contaminant by
aquatic species. The Universal Soil Loss
Equation (USLE) is used to describe
erosion for both the Sludge Management
Area (SMA) and the watershed. While
some commenters criticized the use of
this model as too simplistic, the Agency
believes that USLE provides die most
accepted method for developing such a
national regulation. This equation
incorporates the effect of cover, land
topography, support practices, and soil
credibility. USLE is implemented by
assuming that land use practices and
other characteristics are similar for the
SMA and watershed. An allowable
reference water concentration is derived
based on exposure from ingestion of
contaminated fish and drinking water.
Criteria are designed to protect an
individual who drinks 2 liters of water
and eats 40 grams of fish and shellfish
per day. The consumption of 40 grams
per day represents the 95th-percentile
weighted lifetime diet for individuals
consuming fish and shellfish.
Pathway 13—The vapor pathway is
designed to protect members of a farm
household living at the down-wind edge
of the site and inhaling volatile organic
pollutants from land-applied sewage
sludge. The amount of contaminant
released into the air per second is
estimated as the fraction of contaminant
lost to the vapor pathway (determined
by the mass balance model) divided by
the period of release. A box model is
used to dilute the pollutant releases by
the amount of additional ah" which
enters a box within 2 meters height
above the site. Wind speed is assumed
to be 10 miles per hour (about 4.5
meters per second). Maximum
contaminant loadings are back-
calculated based on a reference air
concentration that corresponds to a HEI
lifetime cancer risk of 1x10 ~4.
-------
9290 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Pathway 14—This pathway is
designed to protect individuals who
obtain their drinking water from ground
water sources, and it assumes that a
well may be located within the treated
site. The model assumes that sewage
sludge is incorporated into the top 15
centimeters of the surface soil layer. In
addition, a reasonable worst-case depth
to ground water is assumed to be l
meter. The allowable pollutant loading
is derived from the health-based
standard, and it accounts for pollutant
degradation and dilution within the
aquifer directly below the site. The
VADOFT finite element module, a fate
and transport mathematical model used
for this evaluation, (Reference Nos. 98
and 99) is used to estimate flow and
transport through the unsaturated zone
and linked to a three dimensional
analytical model AT123D (Reference
No. 117) to depict fate and transport in
the saturated zone. AT123D is used to
simulate the horizontal transport of
contaminant from the entire land
surface to the down-gradient edge of the
silo. For contaminants entering the
saturated zone at the down-gradient
oclgo, no further horizontal transport is
simulated.
The Agency believes that revisions
made to proposed Pathways 11,12A,
and 12W represent refinements to the
models, modeling parameters and
assumptions. The Agency also believes
that these revisions improve exposure
assessment precision and accuracy,
yielding results that are consistent with
protection of public health and the
environment and well within acceptable
risk levels established by the Agency.
As has been previously noted, the effect
of using very conservative assumptions
for model parameters is to compound
the conservatism resulting in an
unreasonably worst-case approach that
yields numerical pollutant limits more
stringent than required to protect public
health and the environment from
reasonably anticipated adverse effects.
2. Human Exposure From Diet
Comment: Several commenters stated
that the human dietary exposure
scenario for agricultural land
application and distribution and
marketing (D&M—referred to as sewage
sludge sold or given away in the final
rule) was not properly constructed with
respect to the daily dry matter intake of
various food groups. Under conditions
of long-term exposure, commenters felt
Uiat it was not appropriate to use data
from the age and sex group having the
highest daily consumption in each food
group. Some commenters advocated
using the approach taken in the human
health aggregate risk assessment for the
part 503 proposal. This approach used
national averages from the Agency
Dietary Risk Evaluation System (ORES)
dietary data base. ORES is a
computerized data base used by EPA's
pesticides program to develop pesticide
tolerances on crops. The system
accounts for total commodity
production (both vegetables and
animals) in the United States. The
Agency's pesticide program uses this
data with census information to develop
national estimates, grouped by age and
sex, of commodity consumption.
One commenter objectedTto the
Agency's assumption that 2.5 percent of
the human MEI's vegetable, fruit, and
grain diet was from sewage sludge-
amended fields in the agricultural land
practices exposure scenario. The
commenter stated that the Agency
estimated that approximately 0.02
percent of the nation's agricultural land
was treated with sewage sludge each
year. Therefore, no more than 0.02
percent of an individual's diet could
originate from food grown on sewage
sludge-amended soil. Since the Agency
recognized that some individuals would
have greater exposure than others, EPA
assumed 2.5 percent of the MEI's
vegetable, fruit, and grain diet was
grown on sewage sludge-amended
fields. The commenter maintained that
this 100-fold increase based on
potentially high consumption of foods
grown on sewage sludge-amended fields
and obtained from roadside stands was
too high and, therefore, unnecessarily
conservative. However, another
commenter provided limited data
showing potentially high consumption
of foods grown on sludge-amended
fields by farm families.
Response: EPA agrees that a more
realistic human dietary exposure
scenario should be used in calculating
human food-chain risk from consuming
plant or animal products that have been
grown or raised on sewage sludge-
amended fields.
In the proposed rule, the quantity of
each of eight food groups in the human
diet assumed in the analysis was taken
from the Pennington data base for the
age and gender group with the highest
daily consumption. While the assumed
diet includes an average mix of meats,
fruits, legumes, grains, and dairy
products, the consumption rates were
higher than would be expected for a
single individual over a lifetime.
In the risk assessment for the
proposal, EPA used the highest
consumption for all age and sex groups
to represent the human diet from 0 to
70 years. As a result, the diet of the
teenage male (14-16 years of age) was
used to represent the consumption of
grains, potatoes, root vegetables, dairy
products, and dairy fat. The diet of the
adult female (25-30 years of age) was
used to represent lamb and lamb fat
consumption. Consumption of legumes,
garden fruits, beef, beef fat, poultry,
poultry fat, pork, and pork fat was
represented by the data for adult males
(25-30 years of age). The diet of the
adult male (60-65 years of age) was
used to represent consumers of beef
liver, beef liver fat, and eggs. Depending
on whether the pollutant being
evaluated was organic or inorganic,
either total meat consumption or only
meat fat was considered in the
evaluation. It was assumed that the
metals would collect in the total tissue
mass, but organic pollutants would be
found only in the lipid portion of the
exposed animals' tissues. The Agency
now believes that the additive effects of
these conservative assumptions yielded
an unreasonably worst-case exposure
assessment approach for the proposed
rule.
However, EPA disagrees with the
comment that the Agency's assumption
for agricultural land practices stating
that 2.5 percent of the MEI's diet comes
from vegetables, fruits, and grains grown
on sewage sludge-amended soil is too
conservative. The data from one
commenter shows farm families do exist
that consume a higher amount of their
diet (i.e., vegetables, meat and milk)
from fields fertilized with sludge. The
Agency reviewed information
(Reference No. 9) that estimated the
percentage of total available cropland
that would be required, based on
nitrogen content, to dispose of the total
United States sewage sludge production.
Estimates for 1985 (based on 1975 data)
ranged from 0.49 to 1.98 percent. This
estimate could be much higher on a
statewide basis, especially in areas
where available cropland is small
compared to the population size (such
as in New Jersey). This assumption was
also supported by the EPA Science
Advisory Board, which recommended
the Agency use 2.5 percent as a
reasonably protective value. To date, the
Agency has not received any study or
data that would suggest a more
reasonable or accurate estimate for a
national regulation. The Agency
believes that it can use a more
reasonable assumption for the fraction
of food groups grown on sludge-
amended fields because other
parameters in the exposure assessment
for this pathway (e.g., the oral reference
dose, the total background intake of
pollutants from all other sources of
exposure except sludge, the uptake
response slope of pollutants in plant
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9291
tissue, etc.) are bounding, and to use
overconservative assumptions for every
model parameter compounds the
conservatism beyond "reasonable"
worst-case conditions. This is why the
Agency did not construct exposure
pathways for agricultural land
application based solely on data from
farm families that consume a higher
amount of their diet from crops or
animals raised on sludge-amended
fields. The Agency believes the
agricultural pathways used in the final
rule adequately protect farm families
because of the compounding affect
bounding parameters used in the
exposure pathway have on less
conservative ones.
As part of EPA's exposure assessment
for land application, the Agency
evaluated Pathway 2, which is
specifically designed to protect HEIs
that consume very large portions of their
diet (as much as 60 percent) from crops
grown in a garden fertilized with sewage
sludge. In the final land application
regulation, EPA used numerical
pollutant limits from Pathway 2 when
those limits were more protective of
human health and the environment than
pollutant limits from other pathways.
Therefore, the Agency evaluated each of
the 14 exposure pathways for land
application but only used the numerical
pollutant limit from the pathway that
was most protective of public health
and the environment regardless of
which pathway produced that limit. For
example, if a pathway protecting
earthworms produced a more protective
(lower) pollutant limit than a pathway
protecting humans, the final part 503
regulation would use the numerical
pollutant limit from the earthworm
pathway as the pollutant limit in the
final rule. By taking the most protective
pollutant limit from the most sensitive
pathway, the Agency is assured of
protecting both public health and the
environment under a variety of
reasonably worst-case exposure
scenarios.
Final Action: EPA has revised its
human dietary exposure scenario for
agricultural land application and
sewage sludge sold or given away
(referred to as D&M in the proposal) to
produce more realistic values
representing a lifetime average
consumption for both sexes analyzed for
each food group. This approach is
similar to the approach used in the
human health aggregate risk assessment
for the proposed rule and to the dietary
analysis the Agency uses to evaluate
risks from pesticides used on human
food-chain crops.
The approach for the final rule
involves integrating the consumption
rates for each sex over their lifespan and
calculating a weighted lifetime average
value. This approach is based on the
same Food and Drug Administration
(FDA) data used in the proposal.
However in the revised approach, each
age-by-sex sample is used to assign food
intakes to different age ranges of the
population. These ranges are then
summed to provide a lifetime average
daily intake of each food group in the
dietary exposure pathways.
The aggregate risk assessment for the
final part 503 rule uses the Agency's
DRES dietary data base. The Agency did
not use the DRES system in its exposure
pathway assessment to develop
numerical pollutant limits for the final
part 503 rule because the exposure
pathways developed by the Agency for
sludge required dry weights of
vegetables and animal tissue consumed
by the HEI and the DRES data is based
on wet (fresh) weights. In order to use
the DRES system in the exposure
pathway assessment for sludge the
Agency would have had to convert each
vegetable and animal food group to dry
weight, which would have introduced
another area of uncertainty in the
exposure assessment.
In Round Two, EPA is committed to
adopting the DRES system for both the
aggregate risk assessment and the
exposure pathway assessment. The
Agency will make the necessary changes
in its exposure assessment for sludge to
adopt the DRES dietary data base. The
Agency is adopting the DRES system to
ensure consistency between future part
503 rulemakings and other regulations
being developed by the Agency but does
not believe that this change will make
a significant difference in the numerical
pollutant limits compared to the
approach used for today's final rule.
3. Fraction of Vegetable Food Groups
Home-Produced with Home Garden
Fertilizer Products
Comment: Many commenters
maintained that the EPA's choice of
values representing the fraction of
vegetable food groups home-produced
with home garden fertilizer products is
too conservative. Several of the
commenters stated that the data taken
from the U.S. Department of Agriculture
(USDA) 1965-1966 market-basket
survey of U.S. food consumption used
to calculate the values in the part 503
proposal were outdated, with the
percentage of homegrown foods
showing a decreasing trend over time.
One commenter contended that the
availability of sewage sludge products is
greater in urban areas; therefore,
households in these areas have a greater
opportunity to use those products in
their vegetable gardens than the rural
farm dweller. For this reason, the
commenter felt that the urban
household dweller should be used by
the Agency instead of the rural farm
dweller. Another commenter argued
that the Agency was inconsistent—it
assumed the exposed individual was a
rural farm dweller growing a high
percentage of his own vegetables; but
the daily intake values for these
vegetables were based on an urban diet.
In this case, the commenter felt that
either a rural or urban setting should be
assumed in both cases for consistency in
the final rule. One commenter suggested
that the Agency use data for the rural
non-farm household instead of the rural
farm family because the Agency
assumed that the land would be
converted from agricultural to
residential use in five years.
Response: The Agency agrees that its
choice of values representing the
fraction of vegetable food groups
produced with sewage sludge home
garden products was too conservative. It
also agrees that it would be preferable
to use more recent data to estimate these
values for the final rule. The USDA
1965-1966 market-basket survey data
used as the basis for the exposure
assessment aggregated all U.S.
households into rural farm, rural non-
farm, and urban categories (Reference
No. 56). To be conservative, the Agency
chose the rural farm household in the
exposure assessment for the proposal.
The Agency now believes that this
assumption was too conservative
because farmers are more likely to use
chemical fertilizers or sewage sludge
cake rather than the typical bagged
sewage sludge products distributed and
marketed in commerce.
As indicated by the public comments,
the rural non-farm household having a
large amount of property but not
operating a commercial agricultural
farm business would be a more
appropriate category for the exposure
assessment scenario. However, the latest
market-basket survey conducted in 1978
by USDA (Reference No. 57) aggregates
the data differently than the 1965-1966
survey. The 1978 survey divides the
U.S. population into non-metropolitan,
suburban, and central city household
categories. The non-metropolitan
category merges the rural farm and the
rural non-farm households together; but
because of the way the survey data was
collected, these two sub-categories
cannot be easily separated for use in the
exposure assessment for the final part
503 rule.
If the Agency were to use the data
from the non-metropolitan category to
represent the rural non-farm household,
-------
9292 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
this again would be unnecessarily
conservative since the category includes
rural farm households who consume a
much higher percentage of homegrown
food than rural non-farm families.
However, data shows that 46 percent of
U.S. households produce some of their
own food from home gardens (Reference
No. 38a), and this information could be
used as a conservative method for
segregating rural farm and the rural non-
farm sub-categories. In addition, the
Agency does not believe that the 1965-
1066 survey data for urban dwellers or
the 1978 survey data for suburban or
central city household categories would
protect public health if used in the
exposure assessment scenario to protect
individuals using D&M products to
produce homegrown food for personal
consumption. The Agency desires that
data used in the exposure assessment
for the final part 503 rule be suited for
the purpose intended and scientifically
defensible, and that the results obtained
from the data adequately protective of
public health and the environment.
Final Action: Based on scientific peer
review and public comments, the
Agency has decided to adjust the
fraction of food groups from the non-
metropolitan category of the 1978 USDA
survey data by a multiplication factor of
2.17. This factor was derived from the
fraction of U.S. households (46 percent)
that produce some of their own food
from home gardens; it is the basis for
deriving the fraction of vegetable food
groups homegrown with D&M products
used in the exposure assessment for the
final part 503 rule. This replaces the
rural farm family exposure scenario
from the USDA 1965-1966 market-
basket survey (Reference No. 56) used in
tho proposal with the more recent 1978
USDA survey data; it uses a reasonable
worst-case estimate of the fraction of
vegetable food groups for non-rural farm
families that was included in the non-
metropolitan category.
4. Fraction of Animal Product Food
Groups Derived From Sludge-Amended
Soil
Comment: Several commenters argued
that tho values representing the fraction
of moat products derived from sewage
sludge-amended soil in the proposed
port 503 regulations for agricultural land
practices are unrealistically high and
based on outdated information from the
USDA 1965-1966 market-basket survey
(Reference No. 56). The commenters
contended that current data on food
consumption by rural farm families may
show a lower fraction of locally grown
livestock consumed by the highest
consuming households.
Response:The Agency agrees that it
would be preferable to use the most
recent information possible to estimate
the values representing the fraction of
animal product food groups derived
from sewage sludge-amended soil in the
exposure assessment for agricultural
land practices. These values in the
proposed regulations were estimated as
an average percent of the annual
consumption of food which is
homegrown by rural farm households.
These values were calculated from the
USDA 1965-1966 market-basket survey
data found in Table 4-14 of the
proposed Land Application
Methodology. The exposed individual
in this assessment was conservatively
assumed to consume 44 percent of meat
(beef, lamb, and pork), 34 percent of
dairy products, 34 percent of poultry,
and 48 percent of eggs from farms
raising livestock on sewage sludge-
amended soil.
The USDA 1965-1966 survey data,
used as the basis for estimating the
values in the exposure assessment,
aggregated all U.S. households into rural
farm, rural non-farm, and urban
categories. To be conservative, the
Agency chose the rural farm household
to use in the exposure assessment for
the proposal. However, the latest USDA
market-basket survey conducted in
1978, aggregates the data differently
than the 1965-1966 survey. The 1978
survey divides the U.S. population into
non-metropolitan, suburban, and central
city household categories. The non-
metropolitan category merges the rural
farm and the rural non-farm households
together; but because of the way the
survey data was collected, these two
sub-categories cannot be separated for
use in the exposure assessment for the
final part 503 rule. In addition, the
Agency lacks any national information
on the consumption of homegrown meat
products that would enable it to adjust
the data in the non-metropolitan
category, previously done for vegetable
food groups.
If the Agency were to use the data
from the non-metropolitan category to
represent the rural farm household, this
would not be as conservative as the
proposal since it includes rural non-
farm families who are not expected to
consume a significant portion of animal
products raised on sewage sludge-
amended lands. However, the Agency
believes that using the unadjusted data
from the non-metropolitan category
would be adequate to protect public
health, given other reasonable worst-
case assumptions used in the exposure
scenario. Further, the Agency does not
believe that the 1978 survey data for
suburban or central city households
would protect public health if used in
the exposure assessment to protect
individuals consuming meat products
from farms raising livestock on sewage
sludge-amended soil. As stated earlier,
the Agency believes that data, used in
the exposure assessment for the final
part 503 rule should be suited for the
purpose intended, scientifically
defensible, and protective of public
health and the environment.
Final Action: The Agency has decided
not to retain for the final rule the values
representing the fraction of animal
product food groups based on the USDA
1965-1966 market-basket survey
because more recent data are available
from the USDA 1978 survey. The
Agency believes that while the 1978
data are not as conservative as the 1965-
1966 data, they do provide a reasonable
worst-case estimate of animal product
food groups consumed by rural farm
families and are protective of public
health given other conservative
assumptions used in the exposure
assessment.
5. Soil Ingestion Rate for Children
Comment: In the proposal, Pathway
2F (Pathway 3 of the final part 503 rule)
used an estimated soil ingestion rate for
children of 0.1 grams per day to derive
numerical limits for agricultural land
practices and D&M. Comments were
received on both sides of this issue.
Some commenters stated that the rate
was too high and that not all the soil
ingested would be sewage sludge-
amended soil, while others felt it was
too low. The range of soil ingestion rates
suggested by the commenters was from
0.1 to 0.5 grams per day. The values
offered for percent of soil that should be
considered sewage sludge ranged from
10 to 50 percent of the total soil
ingested. One commenter suggested that
the soil ingestion rate should be 0.2
grams per day, because this was the
value given in a recent EPA health
advisory (Reference No. 96).
In addition, several commenters
maintained that the Agency's 10
kilogram body weight assumption is too
low for a child, ages 1 to 6, ingesting
sewage sludge-amended soil. The
commenters felt that it was
unreasonable for the Agency to assume
a constant body weight of 10 kilograms
for a child during a 5-year period in
which the body weight usually
increases drastically. The commenters
maintained that a child MEI typically
weighs 10 kilograms for only 1 year, and
suggested that the Agency use a 15
kilogram body weight as a more realistic
value that would not over estimate the
average daily dose for the 5-year period
of exposure.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9293
Response: In the exposure assessment
approach for the proposed rule, the
Agency felt that using children
exhibiting pica behavior (i.e., ingesting
0.5 to 5.0 grams of soil per day) as the
MEI for the children-eating-soil
pathways (Pathway 2F) was too
conservative. Instead, the Agency used
the average value of 0.1 grams per day
as the soil ingestion rate for children.
For the proposal, the Agency considered
this to be a good estimate of the mean
value (Reference No. 101) because all
studies of soil ingestion by children
were short-term measurements, with no
way to estimate (long-term) time-
averaged soil ingestion by a child either
with pica behavior or who inadvertently
ingests soil. The observed variability
between children overstates the true
variability of long-term exposure.
In addition, EPA did not specifically
evaluate the long-term ingestion of pure
sewage sludge because the Agency
believed that the sewage sludge and soil
would be mixed together by mechanical
or natural weathering processes (i.e., a
mixture ranging from 0.25 to 2.5 percent
sewage sludge after dilution with 15
centimeters of soil). Therefore, long-
term ingestion of 0.1 grams of sewage
sludge-amended soil per day was
considered a reasonable expectation.
While the use of an average soil
ingestion rate of sewage sludge-
amended soil, rather than the use of an
ingestion rate associated with a pica
child (0.5 to 5.0 grams per day) and pure
sewage sludge might be construed as
under-protective, other factors suggested
that the Agency's analysis may be over-
protective. First, the entire 0.1 grams of
soil ingested per day was assumed to be
composed of sewage sludge-amended
soil. In real situations, only a portion of
the 0.1 grams per day of soil is likely to
be from sewage sludge-amended soil
since children are exposed to other
sources of household dust and dirt, and
from sources of soil outside the home
environment. Second, it is unlikely that
a child would ingest 0.1 grams of a
sewage sludge-soil mixture every day.
Third, and possibly most important, the
biological availability of sewage sludge-
soil-bound pollutants was assumed to
be equal to that of the pollutants in food
and drinking water. However, evidence
indicates that desorption from the soil
particles is a very slow process,
generally requiring more time than
available to material that is traversing
the alimentary canal. Such desorption
would have to take place before the
pollutant could cross the membranes
into the blood stream and be transported
to sites in the body where it could cause
toxic effects. Fourth, because the
Agency does not have RfDs for
pollutants representing a short term
exposure (i.e., a 5-year exposure),
lifetime RfDs representing a 70-year
chronic exposure were used for
pollutants evaluated in this pathway.
This over predicts the pollutant-dose
the child receives relative to the toxic
threshold (RfD) used, because the
lifetime RfDs protects the child for 70
years from ingesting pollutants in
sludge when in actuality the child
would grow out of this "pica-like"
behavior in approximately 5 years.
The Agency agrees that the 10-
kilogram body weight assumption is too
low and may overestimate the average
daily dose for a child, ages 1 to 6,
ingesting sewage sludge-amended soil.
At the time of proposal, studies on
blood lead concentrations in children
exposed to lead-containing dusts
indicate that maximum exposure via
hand-to-mouth contacts occur at about
18 months of age where the child's body
weight would be approximately 10
kilograms (Reference No. 101).
Final Action: Since the proposal,
several groups have examined the
ingestion rate and body weight issues
and supported research efforts to resolve
them. A recent directive from the
Agency's Office of Solid Waste and
Emergency Response suggested a range
of soil ingestion rates of 0.1 to 0.2 grams
per day (Reference No. 96) for a 16-
kilogram child. For the final Part 503
rule, the Agency has selected 0.2 grains
per day as a best estimate of daily
sewage sludge ingestion by children
with a body weight of 16 kilograms. The
Scientific Peer Review Committee on
land application recommended that 0.5
grams per day soil ingestion (at the
95th-percentile) would be a more
reasonable worst-case exposure level for
children (Reference No. 58). However,
after further evaluation, the committee
agreed that this is an overestimation of
chronic risk associated with soil
ingestion by children ages 1 to 6.
The Agency believes that using either
a sewage sludge ingestion rate of 0.2
grams per day for 5 years or 0.5 grams
per day for 2 years will result in the
same amount of exposure and will be
suitable for modeling children at higher
risk. Therefore, the Agency has selected
a sewage sludge ingestion rate for
children of 0.2 grams per day to use in
exposure Pathway 3 to derive numerical
limitations for agricultural land
practices in the final rule. In addition,
the Agency has decided to use the 16-
kilogram body weight assumption for
children ingesting sewage sludge in this
pathway.
6. Ingestion of Soil by Animals
Comment: Seven commenters took
issue with the EPA's assumption that 8
percent of a grazing animal's diet
contains sewage sludge-amended soil.
The commenters considered that the 8
percent sewage sludge/soil ingestion
used for Pathways 4 and 6 in the land
application exposure assessment for the
proposed rule was too high based on
chronic sewage sludge ingestion by
cattle in field studies where sewage
sludge or compost was surface applied
to growing pasture. They suggested that
a value based on long-term grazing
under average field conditions was more
appropriate than assuming short-term
grazing under poor field conditions.
They further stated that in order for
pasture-fed livestock to ingest 8 percent
of their diet as sewage sludge-amended
soil over a lifetime would require an
extremely underdeveloped pasture as
their sole source of food. In a normal
pasture setting, livestock eat the ends of
the grass which contains little adhering
soil. Pulling up plants with roots and
adhering soil attached usually occurs
only when adequate developed mature
grass is not available. This could occur
during extreme drought conditions, but
it is not likely for the entire lifespan of
the animals. The commenters suggested
a range from 1 to 5 percent of the
grazing animals' diet be composed of
sewage sludge-amended soil.
In addition, the commenters noted
that in any one year, the maximum
fraction of a farm treated with sewage
sludge ranges from 10 to 33 percent,
rather than the 100 percent assumed in
the proposed exposure assessment. The
commenters suggested that the Agency
multiply its values by one-tenth to one-
third to reflect the actual fraction of
acreage set aside for sewage sludge
application.
Response: The Agency agrees that the
8 percent ingestion of sewage sludge-
amended soil by grazing animals
considered in Pathways 4 and 6 for the
land application proposed regulations
was too conservative (Pathways 5 and 7
in the final rule). EPA assumed that
relatively large amounts of soil would
be ingested by grazing animals because
some studies reviewed prior to
developing the proposal had reported
these or higher values. The Agency also
assumed a dilution of sewage sludge
with 15 centimeters of soil when the
sewage sludge is applied to pastures.
Since the sewage sludge applied to
pastures is generally not incorporated
into the soil (as it is for row crops), the
Agency's assumption relied on climatic
conditions and biological factors to
assure mixing to the 15-centimeter
-------
9294 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
dopth. The Agency feared that this
assumption may underestimate grazing
animals ingesting sewage sludge in even
creator concentrations than those
determined in the exposure assessment
model because this assumption
depended on incorporation through
weathering.
Based on the submission of new
information from a long-term study
reported by Chancy et. al. (Reference
No. 11), the Agency has revised its
sewage sludge-amended soil ingestion
assumption for grazing animals
(Reference No. 58). In the study, sewage
sludge ingestion was estimated from
season-long analyses of feces of animals
grazing in pastures receiving surface-
applied liquid sludge or compost. The
study concluded that the average intake
of sewage sludge was 2.5 percent of a
grazing animal's dry diet. Other
information indicated that in any one
year the maximum fraction of a farm
treated with sludge was 33 percent.
Therefore, the actual fraction of the
grazing animals' diet which is sewage
sludge would be lower than 2.5 percent
if the animals are rotated among several
pasture fields.
The Agency believes that exposure
from surface-applied sewage sludge, as
shown in the study, represents a much
greater potential for ingestion than
sewage sludge mixed with the top 15
centimeters of soil used in the exposure
assessment pathways for the proposed
rule. In addition, whole season data are
more appropriate than using single
highest results in the exposure
assessment because prolonged exposure
is usually required before toxic levels
can cause adverse effects. The Agency
also believes that animals are rotated
among several fields and that many
farms do not apply sewage sludge to 100
percent of their land in any one year.
This would tend to lower the fraction of
tho livestock's diet affected by recent
sowago sludge applications.
Final Action: Basod on new
information and data submitted during
tho public comment period, the Agency
has revised the maximum fraction of a
farm treated with sewage sludge and the
sewage sludge-amended soil ingestion
assumption for grazing animals used in
exposure assessment Pathways 5 and 7
(Pathways 4 and 6 in the proposed rule).
The exposure assessment for the final
rule used 33 percent as the maximum
fraction of a farm treated with sewage
sludge and 1.5 percent sewage sludge
(season-long average) in the diet of
livestock grazing pastures amended 30
days before the animals enter the Reid.
Tho Agency believes that over time (1)
the freshly applied sewage sludge will
become mixed with the previously
applied sludge and soil surface and (2)
grazing livestock can ingest the sewage
sludge on the soil surface. The Agency
believes, however, that the fraction of
farmland treated and the rate of sludge
ingestion is significantly less than the
100 percent and 8 percent assumptions
used in the proposed rule.
7. Plant Uptake and Phytotoxicity
Comment: Many commenters
recommended that Pathway 7 (Pathway
8 in the final rule) be completely
removed from the land application
exposure assessment model.
Commenters stated that because of the
complex nature of the soil-plant-sludge
interacting system, pinpointing the
exact cause of the crop yield response
is difficult. Since sewage sludge
contains a mixture of potentially toxic
chemicals, predicting with a high degree
of confidence that any observed adverse
effect is a result of a particular pollutant
acting alone or the result of synergistic
effects from a combination of pollutants
acting together is difficult. Furthermore,
some commenters believed that this
pathway should not be evaluated
because it is essentially self-limiting. If
a particular quality of sewage sludge
caused phytotoxic effects, such as yield
reductions, farmers and the public
would cease using it.
In the risk assessment evaluation for
the proposed rule, phytotoxicity and
plant uptake data were chosen based on
a selection hierarchy. This hierarchy
grouped data from most preferred (i.e.,
"most like the conditions being
regulated") to least preferred (i.e., "least
like the expected conditions to be
regulated"). For example, the most
preferred studies from which to extract
data points were performed under
sludge/field conditions followed by
sludge/pot conditions and the least
preferred were pure organic compounds
or salt/pot studies.
Numerous public comments were
received on this approach. The majority
stated that the use of salt or pot studies
was an unreasonably worst-case
situation that would drastically over-
estimate plant uptake and phytotoxicity
of sewage sludge pollutants. Studies
using salt spikes instead of sewage
sludge result in greater bioavailability of
the metallic pollutants because they are
not bound to an organic matrix and are,
therefore, more freely taken up by plant
roots.
Likewise, greenhouse studies where
plants are grown in pots are known to
often over predict uptake compared to
field conditions. This is because pots
tend to restrict the area of root growth
and the small amount of contained soil
tends to concentrate and retain the
sewage sludge pollutants around the
roots, thus accelerating uptake. Under
field conditions, precipitation can
disperse pollutants into the soil profile
so that they are less available to the
plants. In fact, numerous differences
exist between the pot and field
environments, such as the molecular
form of the pollutant under
consideration.
Response: The EPA disagrees that the
phytotoxicity pathway (Pathway 8 in
the final rule) should be removed from
the land application exposure
assessment model because it is self-
limiting (i.e., farmers would not use a
product that diminishes or eliminates
plant productivity). The Agency
believes phytotoxic effects should
continue to be modeled even if they
could become self-limiting. This is
because the phytotoxicity effects could
be harmful and cause economic losses
initially before these effects could be
observed. In addition, sewage sludge
could be applied to areas that do not
have commercially valuable plant
species but could still have pollutant-
sensitive plant species that exhibit
phytotoxicity resulting in secondary
environmental impacts, such as erosion.
The Agency believes that the public
should not have to determine the
adverse impacts of using sewage sludge
by conducting their own field trials. The
potential for adverse outcomes might
cause the public to stop using sewage
sludge products, thus confounding the
Agency's stated policy of encouraging
beneficial reuse.
The Agency, however, agrees that
sewage sludge/field studies should be
used in place of salt or pot studies when
such data is available and technically
defensible. At proposal, incomplete
information was available concerning
sewage sludge pollutants, fate, transport
and effects, and the means of sewage
sludge use and disposal. However,
rather than wait for more complete
information in order to propose the
regulations, the Agency proposed
standards for those pollutants and use
or disposal practices for which it had
sufficient information, and solicited
additional information from the public
and scientific community during the
public comment period. Section 405
specifically contemplates that the
Agency will issue regulations based on
existing information in stages and revise
them periodically.
To remedy information gaps, EPA
worked with experts from both inside
and outside the Agency during the
public comment period to review the
basis of the proposal's scientific and
technical data. As a result, new
information obtained from the scientific
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9295
peer review experts and submissions
from the public have improved the data
used as the basis for the final part 503
rule, which employs mostly sewage
sludge/field studies.
Final Action: In the final rule, the
Agency has decided to continue to
evaluate the phytotoxicity pathway
(Pathway 8) as part of the exposure
assessment for land application
practices and to use, in all possible
cases, field data derived from sewage
sludge to develop the pollutant transfer
co-efficients for this pathway. Much of
the field data was provided by scientific
peer review and public comment on the
proposed rule. This approach has
resulted in more realistic values and
higher allowable sewage sludge
application rates and higher pollutant
loading rates for the actual sewage
sludge-field conditions regulated. The
Agency believes that continuing to
evaluate Pathway 8 provides a greater
degree of public health and
environmental protection, and
demonstrates less pollutant uptake in
crops as well as a lower incidence of
plant phytotoxicity.
8. Minimum Soil pH Requirements
Comment: Many commenters
suggested that lack of soil pH control in
the proposed rule was a gross oversight
on the part of the Agency, because many
studies have shown a direct relationship
between pH and plant uptake of metals.
The commenters maintained that if the
Agency used studies conducted at
certain pH levels in the exposure
assessment models for agricultural land
application practices, then those same
pH levels should be imposed in the final
part 503 rule to ensure consistency
between the results predicted from the
modeling analysis and those achieved in
actual practice. The range of pH levels
suggested for the part 503 rule varied
from 5.5 to 6.5. However, some
commenters objected to pH controls,
arguing that higher plant uptake with
lower pH is not always the case and that
such controls may not be necessary for
all agricultural land practices.
Response: The Agency agrees that
prudence may require pH control for
certain agricultural land practices to
ensure that exposure assessment model
assumptions and results reflect actual
field conditions. In developing the
exposure assessment pathways for
agricultural land practices, the Agency
used data on the plant species most
sensitive to pollutants. Depending on
the pollutant, the more sensitive species
were generally leafy green vegetables,
root crops, or legumes. Data taken from
phytotoxicity studies generally had soil
pH at 6.5 or greater because farmers
generally used this condition to
maximize crop productivity. A recent
review of available data indicates that
metal absorption by plants at a soil pH
of 5.7 to 6.0 is the same as at a pH of
6.4 oz. greater (Reference Nos. 28 and
113).
The Agency recognizes that soil pH is
one of the strongest influences on the
capability of plants to absorb pollutants
from the sewage sludge/soil matrix.
However in some cases, data from low
pH studies were also used in the
exposure assessment model to develop
the numerical limitations for
agricultural land practices. Therefore,
the Agency believes the numerical
limits protect a majority of U.S. soil
conditions without requiring pH control
for all agricultural land practices
regulated under the part 503 rule.
Final Action: The Agency has decided
to continue to use studies conducted at
pH levels that reflect a majority of U.S.
soil conditions to derive the numerical
limitations for agricultural land
practices as part of the final part 503
rule. The Agency believes that these
numerical limitations protect public
health and the environment without soil
pH control for all agricultural land
application practices. The exposure
assessment includes data that reflects
low pH soil conditions so resulting
numerical limits provide an adequate
level of protection under a range of soil
conditions. The Agency recognizes that
unusual conditions not fully outside
modeled parameters may not be as
protected but believes that this is
mitigated by the conservatism of other
factors used in the exposure assessment
including sensitive species. The result
of not regulating minimum soil pH
would simply mean that under some
unreasonably worst-case conditions the
numeric limitations would not be as
protective as the reasonably worst-case
conditions selected for the final rule.
9. Relative Effectiveness of Exposure
Comment: Several commenters
objected to the Agency using a relative
effectiveness of exposure value (RE) of
one for all pollutants in the exposure
assessment for agricultural land and
D&M (referred to as "sale or give-away"
in the final rule) practices. The
commenters felt that sewage sludge-
borne inorganic and organic pollutants
do not have the same toxic effects on
humans and animals when ingested
from forage or food grown on sewage
sludge-amended fields and that such an
assumption is overconservative.
Further, the commenters noted that this
assumption implies that no observed
differences exist in absorption among
various exposure routes and that 100
percent of a pollutant from an exposure
route is absorbed and taken up by the
target tissue. They urged the Agency to
try to develop more reasonable
estimates of the RE value for the various
exposure routes.
Response: The relative effectiveness
of exposure value as used in the
exposure assessments for agricultural or
D&M practices is a unitless factor that
shows the relative lexicological
effectiveness of an exposure by a given
route when compared with another
route, (i.e., the relative effectiveness of
exposure value relates the toxicological
effect of a pollutant to a receiving
organism through a specific exposure
pathway (e.g., inhalation) instead of a
reference pathway (e.g., ingestion
through food) used to develop an RfD or
Q* value for a pollutant.) For example,
carbon tetrachloride and chloroform
were estimated to be 40 and 65 percent
as effective when exposure occurs,
respectively, by inhalation as by
ingestion. In addition to route
differences, RE can also reflect
differences in the exposure conditions
(e.g., absorption of nickel ingested in
water has been estimated to be five
times greater than when ingested in
food).
The Agency agrees that it should
develop reasonable estimates of the RE
value for the various exposure
assessment pathways. However, it is
widely recognized that the RE factor
should only be applied where well-
documented and referenced information
is available on the pollutant's
pharmacokinetics. When such
information is not available, the
Agency's policy is to conservatively set
RE equal to one to ensure protection of
public health and the environment.
Since these data were not sufficiently
well-documented at the time of the
proposal, all of the RE factors used in
the risk assessment were assumed to be
one.
Final Action: After proposal of the
part 503 regulations, the Agency
undertook a more extensive literature
search to identify the correct RE values
for land application practices. For
example, studies by Hinesly et al.
(1985), in which female chickens were
fed diets containing three levels of
biologically incorporated cadmium,
demonstrated that after 80 weeks the
hens retained only 1.3, 0.98, and 0.87
percent of the total ingested cadmium
(Reference No. 33). Similar results were
obtained from studies with pheasant
and sows (Reference Nos. 34 and 30).
Recent data from long-term field
studies have shown that sewage sludge
properties influence pollutant
bioavailability through binding of the
-------
9296 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
pollutants by the sewage sludge itself.
However, the research data base on the
fate of many sewage sludge-borne
pollutants is still extremely limited. As
a result, uncertainties about the health
effects and threshold exposures of these
pollutants has made the risk/exposure
assessment for these pollutants difficult.
Therefore, the Agency has decided to
continue to use RE values equal to one
for those pollutants with limited data
but has revised its RE values where
sufficient scientifically defensible
information was available indicating the
bioavailability of the pollutant was less
than 100 percent. The Agency
recognizes that in some cases this may
result in numerical limits that may be
more protective than necessary;
however, EPA believes that it is prudent
to have a balance of mid-range and
bounding parameters in order to protect
highly exposed individuals.
10. Soil Incorporation and Density
Comment: Three commenters argued
that for EPA to assume that surface-
applied sewage sludge would be fully
mixed in the top 15 centimeters of soil
duo to climatic conditions and
biological factors was unrealistic. They
suggested that EPA consider sewage
sludge/soil incorporation of less than 15
centimeters. The commenters felt that
biological and physical processes would
result in some mixing of surface-applied
sewage sludge so that animals and
humans would not be exposed to
undiluted sewage sludge, but they
submitted no data to support a
particular value.
One commenter criticized EPA for
failing to describe how the soil
incorporation depth and bulk density
values wore derived for the proposed
rule. The commenter also questioned
why those parameters were not
evaluated in the proposal's sensitivity
analysis.
Response: EPA disagrees that its soil
incorporation assumptions are
unrealistic. In the proposed rule for
agricultural land and D&M practices, the
Agency assumed that sewage sludge is
incorporated into the top 15 centimeters
of the soil. For pathways involving plant
absorption of a pollutant, the actual
depth of soil incorporation should make
relatively little difference. This is true
because the mean concentration in the
root zone is likely to be more important
than the distribution of the pollutant
within the root zone. However, for
pathways involving direct ingestion of
soil by animals or children, the assumed
depth of incorporation has greater
importance.
EPA recognized that homeowners
fertilizing their lawns are unlikely to
incorporate the sewage sludge product
into an already established lawn.
Instead, they would just spread it on the
surface where small children could be
exposed. Alternatively, animals grazing
on pastures may pull up shallow roots
with the foliage, thereby ingesting
greater concentrations of a pollutant
than those assumed in the model.
Nevertheless, homeowners or farmers
may water the lawn after applying the
sewage sludge product, causing the
pollutants to migrate into the soil
profile. Further dilution may occur as
normal precipitation occurs or as worms
and small mammals (e.g., moles) burrow
into the soil. Emergent vegetation would
also tend to disperse the pollutants and
make direct exposure to the sludge/soil
mixture more unlikely. The Agency
believes that man-made and natural
conditions are sufficient to ensure soil
incorporation of sewage sludge and that
the average soil incorporation depth of
15 centimeters is adequate to protect
public health and the environment.
However, for certain pathways that tend
to exhibit a greater exposure to the
pollutants in sewage sludge, the Agency
assumed 100 percent ingestion of
sewage sludge. These pathways are
Pathway 3 (child ingesting sludge used
in a home garden), Pathway 5 (human
who consumes dairy products and meat
from animals that ingest sewage sludge),
and Pathway 7 (animals consuming
sewage sludge adhering to forage crops
or on the soil surface).
The Agency agrees that the final rule
should show how the values for soil
incorporation depth and soil bulk
density were derived. However, a
sensitivity analysis was not performed
on these two parameters for the
proposed rule because the Agency did
not consider these parameters
candidates for site-specific modeling—
the test for whether site-specific
modeling was appropriate. If site-
specific modeling for these factors had
been allowed for agricultural land
practices, the Agency would have
needed to establish the soil type and
incorporation depth for each sewage
sludge-amended field and to perform
exposure assessment modelling based
on these local conditions to ensure
compliance. The Agency therefore
rejected site-specific modelling of these
factors for agricultural land practices as
being too burdensome to implement and
instead established national numerical
limitations based on average values for
soil incorporation and soil bulk density,
15 centimeters and 1.33 grams per cubic
centimeters, respectively.
Final Action: In the absence of new
information and data, the Agency has
decided to retain the average value for
soil incorporation depth (15
centimeters) except for Pathways 3,5,
and 7, and for soil bulk density (1.33
grams per cubic centimeters) in the final
part 503 regulations for agricultural land
practices and sewage sludge sold or
given away for use in home gardens. In
addition, the Technical Support
Document for Land Application shows
the derivation of these two parameters.
11. Background Pollutant Levels in Soil
Two commenters suggested that EPA
should establish site-specific inorganic
pollutant background levels in soil
rather than use a single background
level as input into the exposure
assessment model for agricultural land
practices because background levels of
inorganic pollutants vary widely across
geographical areas. The commenters
said that establishing site-specific
background levels for inorganic
pollutants would provide more
regulatory flexibility and foster
beneficial reuse.
One commenter stated that urban
soils, where D&M sludge products are
widely used, contain higher background
concentrations of inorganic pollutants
than agricultural soils and that EPA's
applying agricultural soil data to urban
settings in the exposure assessment for
the part 503 proposal was inappropriate.
Another commenter argued that
assuming zero background levels for
organic pollutants in soil
underestimates risk, especially for
agricultural soils which could have
received heavy applications of
chlorinated pesticides before sewage
sludge-amendment occurred. In some
cases, the background levels of these
insecticides in agricultural soils (rarely
found in urban settings) can approach
the concentrations found in sewage
sludge. The commenter suggested that
the Agency use average background
levels for organic pollutants in soil as
the baseline for estimating exposure
from further additions of organic
pollutants in sewage sludge.
Response: The Agency disagrees that
any of its exposure assessment
assumptions concerning the background
levels of inorganic and organic
pollutants are inappropriate for
establishing national numerical
limitations for agricultural land and
D&M practices.
For metals, the Agency used an
estimated nationwide median
concentration for agricultural lands as
the background level of metals in soil.
In some cases, the background
concentration of a metal is a significant
fraction of the maximum allowable soil
concentration. In addition, for the
terrestrial Pathways 1 through 9
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9297
(Pathways 1 through 10 in the final
rule), the Agency assumed that once the
metal is applied, it remains on the land
indefinitely. Since no accounting is
made for removal by (1) soil erosion, (2)
leaching, (3) volatilization, or (4)
absorption of the plant and removal of
the harvested portion of the plant, the
Agency believes that this assumption
offsets the less conservative assumption
of using an average value to represent
background metals concentrations.
The ability of plants to absorb metals
from the soil was assumed to be the
same as their ability to absorb metals in
sewage sludge. If higher background
concentrations of metals were assumed,
those numerical limits based on plant
toxicity would be more stringent for
copper, zinc, and nickel. However in
some cases, the higher background
concentrations of metals would exceed
the allowable pollutant concentration in
the soil. At this time, the Agency
believes that selecting more stringent
background levels is unnecessary and
that the levels used in the final rule
protect plants from metal toxicity.
However, as discussed earlier hi the
preamble, the Agency plans to
investigate the impact sludge has on
plants in its monitoring study to
determine what role background levels
and pH play in the uptake of metals by
plants grown on sludge-amended fields.
The Agency also assumed that
chromium in sewage sludge and soils is
generally in the trivalent, not
hexavalent, state. According to the EPA
publication, "Application of Sewage
Sludge to Cropland: Appraisal of
Potential Hazards of the Heavy Metals to
Plants and Animals," by Council for
Agricultural Science and Technology,
Report No. 64, November 15,1976, p. 25
(EPA-430/9-76-013):
Haxavalent chromium remains as such in
a soluble form in soil for a short time but is
eventually reduced to trivalent chromium
and then changed to forms of low solubility.
Haxavalent chromium is toxic to plants, but
sludges contain little, if any, haxavalent
chromium because it is reduced to the
trivalent state during the sewage sludge
digestion process.
This conclusion is also supported by the
findings of Patterson and Kodukula
(JWPCF 56: 432,1984) who determined
metal distributions in activated sewage
sludge systems.
For organic pollutants, the exposure
assessments for agricultural land and
D&M practices were performed to
measure only the incremental
carcinogenic risk over background
levels of organic pollutants, making
measuring or estimating the actual
organic pollutant background levels
unnecessary. In addition, the majority of
organic pollutants regulated in the
proposed rule have short half-lives (i.e.,
less than one year) and are not expected
to remain in the environment for long
periods of time; therefore, they should
volatilize or degrade between sewage
sludge applications.
Final Action: The Holmgren (1985)
database, upon which the median
background metal concentration levels
for the proposal were based, is
considered one of the most thorough
analyses of national uncontaminated
soils available (Reference No. 35). The
Agency has decided, based on reasons
discussed previously, to continue to use
this database in the final rule to estimate
the national median background
concentrations for inorganic pollutants
in soil. In addition, the Agency has
decided to continue to use a zero
background concentration level for
organic pollutants evaluated in the final
rule for agricultural land and D&M
practices.
The Agency recognizes that using a
national median concentration for
inorganic pollutants and zero
concentration for organic pollutants to
represent all agricultural background
pollutant levels would over predict
exposure in some cases while under-
predicting it in others. However, EPA
believes that these assumptions,
including other conservative
assumptions concerning the fate and
transport of metals and organic
pollutants in soil, are adequate to
protect public health and the
environment.
Land Application—Non-Agricultural
Practices
In the part 503 proposal, the Agency
did not conduct a pathway exposure
assessment for non-agricultural land.
Instead, EPA proposed to regulate non-
agricultural uses through capping
sewage sludge concentrations. EPA
established numerical pollutant
limitations for non-agricultural land
application practices using data on
existing sewage sludge quality from the
"40 City Study." This approach
followed a preliminary risk assessment
which determined that those practices
did not result in high levels of human
exposure. Aggregate risk analyses using
the proposed numerical limitations did
not show significant human health
effects on the population as a whole.
The Agency's aggregate risk analysis
for non-agricultural land application
was based upon the assumption that
sludge would be applied to non-
agricultural land under the conditions
provided in the rule. Among these were
restrictions on growing crops and
grazing animals. Consequently, these
proposed management practices would
eliminate any potential for exposure
through many of the 14 potential
pathways of exposure that had been
identified for sewage sludge applied to
agricultural land. Moreover, other
pathways were not considered because,
of their nature, they would not be
applicable (e.g., protection of children
in a home garden setting). Therefore, the
Agency estimated aggregate effects from
human exposure to pollutants in sewage
sludge applied to non-agricultural land
using only two pathways of exposure:
1. Sludge-Soil-Surface Water-Human
(Pathway 11); and
2. Sludge-Soil-Ground Water-Human
(Pathway 12W)
Using data on national application
rates and the two exposure pathways,
the Agency estimated that application of
sewage sludge to non-agricultural land
would result in a maximum individual
cancer risk of 2x10 ~8 based upon the
98th-percentile pollutant concentrations
shown in the "40 City Study." The 98th-
percentile pollutant concentrations were
calculated from a regression analysis of
the values of 25 pollutants in the "40
City Study." The Agency selected the
98th-percentile concentration to prevent
potential deviations from the pollutant
concentrations in the "40 City Study"
and to prevent increases in any risks
associated with the application of
sewage sludge to non-agricultural land.
The Agency believed that this approach
would ensure that sewage sludge quality
would not get worse and, therefore,
assure the continued validity of the risk
assumptions underlying the Agency's
regulatory control decisions.
Peer review and public comments
raised a number of concerns with
permitting the application of sewage
sludge to non-agricultural land at 98th-
percentile pollutant concentrations.
Many commenters were concerned that
the proposed approach was arbitrary (an
artifact of the "40 City Study") and did
not adequately protect public health and
the environment. A complete
description of the 98-percentile
approach and the proposed regulations
for non-agricultural land application is
found in the proposal at 54 FR 5785-
5789, 5798-5800, 5804-5807, 5860-
5861, 5868-5871, 5879-5880, 5895.
Comment: Many commenters
questioned the Agency's use of the 98th-
percentile approach, stating that the
approach has scientific and technical
deficiencies and either over- or
underregulates non-agricultural land
application of sewage sludge, depending
on the pollutants of concern and the
practice. Some commenters stated that
the proposed approach would reduce
the desirability of the non-agricultural
-------
9298 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
lend practices because of the increased
public perception of a human health or
environmental risk. Many commenters
suggested that the Agency divide non-
agricultural land application into
different practice categories. This would
allow the Agency to tailor its exposure
assessment to each non-agricultural
land practice category, thereby
maximizing alternatives for encouraging
beneficial use while protecting public
health and the environment.
Many commenters were concerned
that the numerical limitations derived
from the 98th-percentile approach were
not supported by adequate risk
assessments or substantiated by field
studies. In addition, commenters stated
that the 98th-percentile based numerical
limitations could not be considered a
substitute for evaluating plant and
animal exposure pathways. Some
commenters stated that the approach for
agricultural and non-agricultural land
application practices should be
consistent.
•Response: The Agency agrees with
public and scientific peer review
comments. The Agency's objective is to
encourage the beneficial use of sewage
sludge wherever consonant with
adequate protection of public health and
the environment. To be consistent with
other beneficial reuse practices within
the final part 503 rule, the Agency
developed numerical limitations for
non-agricultural land application of
sewage sludge after an exposure
assessment evaluation similar to that for
"agricultural" land application (see
earlier discussion in this part). Based on
scientific peer review and public
comments, the Agency now believes
that adequate data is available from
direct studies of plants and animals in
non-agricultural sewage sludge
scenarios (or reasonably interpolated
from other sludge studies) to yield valid
results when evaluating risk for
different non-agricultural land practice
categories.
The Agency evaluated all 14
pathways assessed for agricultural land
practices for their applicability to use of
sewage sludge on non-agricultural land.
The Agency believes that not all the
pathways (or assumptions used in
characterizing these pathways) for
agricultural practices are appropriate for
non-agricultural land practices. Thus,
tho Agency has deleted some of the
pathways and revised the assumptions
used in others to be better suited to a
risk assessment for each non-
agricultural land practice category.
However, the Agency has determined
that the new mass balance methodology
and revised Pathways 11,12A, 12W
(Pathways 12,13, and 14 in the final
rule) used to establish final numerical
limits for "agricultural" land
application are also appropriate for non-
agricultural practices and do not require
further modification.
Final Action: Based on public
comments and scientific peer review,
the Agency has revised its exposure
assessment approach for regulating
sewage sludge applied to non-
agricultural land (a practice covered
under land application). The approach
for the final part 503 rule uses an HEI
exposure pathways assessment for three
categories of non-agricultural land
practices: (1) Forest lands, (2) soil
reclamation sites (e.g., lands devastated
by such situations as natural disasters,
strip mined areas, construction sites),
and (3) public contact sites (e.g., parks,
golf courses, campuses, playgrounds,
highway medians, among others).
The Agency recognizes that some of
these categories differ from others
regarding the method of sewage sludge
application (e.g., soil reclamation sites
may have only one or more high rate
sewage sludge applications over a short
time period while public contact sites
may have many low rate sludge
applications over multiple years). For
this reason, the Agency conducted a
separate exposure assessment for each
non-agricultural land application
category. In addition to meeting the
numerical limitations, the application of
sewage sludge must also meet specific
management practices that the Agency
is requiring for non-agricultural land
application.
The final exposure assessment
approach for non-agricultural land
practices uses many of the same
modeling assumptions, exposure
pathways, and target organisms (i.e.,
HEIs) as were used for agricultural land
practices. However, because the Agency
recognizes that the two practices do
differ, some of the exposure pathways
for agricultural land application have
been modified for non-agricultural land
practices. In addition, different
assumptions used within each non-
agricultural practice category have
resulted in the Agency tailoring the HEI
for each exposure pathway specific to
the practice category. A detailed
discussion of the exposure assessment
methodology (i.e., models, pathways,
parameter values, assumptions, and
others) used for non-agricultural land
practices in the final part 503 rule can
be found in the Technical Support
Document for Land Application.
Information on obtaining this and other
technical support documents is
provided in Part XIV—Availability of
Technical Informational on the Final
Rule.
Comments on the Proposed Exposure
Assessment Approach and Risk
Management Issues for Surface
Disposal
Surface Disposal—AH Practices Except
Mono/ills
In the February 6,1989, proposal,
EPA proposed requirements for the
disposal of sewage sludge on a surface
disposal site. EPA did not perform a
pathway-by-pathway exposure
assessment for this method of sludge
disposal for purposes of the proposal.
The Agency defined "surface disposal
site" as an area of land on which only
sewage sludge is placed for a period of
one year or longer. Surface disposal
sites have no vegetative or other cover,
are not part of the POTW's treatment
process, and are not sites used for
temporary storage of sewage sludge
prior to final use or disposal. In
addition, the proposal did not include
monofills under the surface disposal
practice and regulated the two practices
separately.
As proposed, owners or operators of
sewage sludge surface disposal sites
would not need to comply with
extensive management requirements.
This is because the Agency concluded
that surface disposal sites generally are
small, located in rural areas on lands
owned or controlled by local
governments, and do not pose a
significant threat to public health or the
environment. The Agency proposed
numerical pollutant limitations for
sewage sludge disposed at surface
disposal sites based on "current sludge
quality" (i.e., the 98th-percentile
pollutant concentration shown in the
"40 City Study").
Comments/Response: For many of the
same reasons explained previously
(Land Application—Non-Agricultural
Practices—EPA determined that it
would be more appropriate to evaluate
pollutants destined for use or disposal
using an exposure pathway risk
assessment methodology), the Agency
revised its approach for regulating
sewage sludge surface disposal sites.
Instead of establishing pollutant
limitations based on 98th-percentile
sewage sludge quality, which many
commenters felt was arbitrary and not
adequately protective, EPA used
exposure assessment models and
pathways to develop numerical
pollutant limitations based on risk. The
EPA's revised approach for surface
disposal sites is very similar to the two-
tiered approach used for sewage sludge
monofills. A description of the exposure
assessment approach for sewage sludge
monofills is provided in this part,
Surface Disposal—Monofills.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9299
Final Action: In the part 503 proposal,
the Agency proposed to establish
numerical pollutant limitations based
on existing sewage sludge quality for
sewage sludge surface disposal sites.
This was because of the Agency's
preliminary conclusion that such a
disposal would not result in high levels
of pollutant exposure to potentially
exposed individuals. Further, the
Agency's aggregate risk analysis did not
show significant human health effects
on the population as a whole from this
disposal practice. To derive numerical
limitations based on existing sewage
sludge quality, EPA used the 98th-
percentile pollutant concentrations from
the "40 City Study."
Peer review and public comments
suggested scientific or technical
deficiencies in using the 98th-percentile
pollutant concentrations. Many
commenters were concerned that the
proposed approach was arbitrary (an
artifact of the "40 City Study") and not
adequately protective of public health
and the environment. As a result,
today's final part 503 rule regulates both
monofills and surface disposal sites in
one category called "surface disposal."
The rule uses an exposure assessment
approach (similar to the two-tiered
approach for sewage sludge monofills)
for deriving numerical pollutant
limitations for sewage sludge disposed
of in piles or trenches at surface
disposal sites.
The Agency also evaluated the
potential risks to wildlife from
monofills and other surface disposal
practices as part of today's final rule,
and found that wildlife exposure was
not significant enough to develop
numerical limits using the wildlife
exposure pathways for these practices.
The Agency has concluded that there
could be exposure and potential risk to
wildlife that actively forage on surface
disposal sites. However, current
evidence does not indicate significant
levels of foraging or other biological
activities that would lead to significant
exposure for these practices, and that
the management practices required for
surface disposal by the final part 503
rule were adequate to protect wildlife.
In addition, significant ecological
differences generally exist between
these disposal practices and land
application practices where sewage
sludge is applied directly into wildlife
habitats and feeding areas (and for
which the Agency is promulgating
numerical limits and management
practices under today's final rule).
However, EPA has no reason to believe
that exposure is significant for land
application practices either, but as
discussed earlier in the preamble is
committed to studying these practices to
ensure that the part 503 regulation
protects wildlife.
The conditions within sewage sludge
surface disposal sites are physically and
biologically different from the
conditions at land application sites. For
example, because of the physical nature
of these sites, active monofills and other
surface disposal sites do not appear to
provide a suitable habitat (i.e., a place
to live) for many species. Daily disposal
operations, using trucks, bulldozers,
pipelines, and other types of sludge
spreaders, are expected to further
reduce the likelihood that individual
surface disposal sites would be available
for wildlife as a feeding source.
Therefore, wildlife would generally
have to come from habitat areas outside
the surface disposal site to feed. Surface
disposal sites are often at least partially
separated from habitat areas by
industrial activity and structures, which
would impede access to these sites.
Thus, wildlife are not expected to have
significant exposure from these
practices. Therefore, wildlife exposure
pathways for surface disposal practices
(including monofills) were evaluated
but not used to establish numerical
pollutant limitations for use in the two-
tiered approach for the final part 503
rule.
Under the two-tiered approach for
surface disposal sites, sludge whose
concentration would not permit
disposal under the first tier would be
subject to alternative limitations
established under the second tier. The
first tier derives one set of national
numerical limitations for pollutants
found in sewage sludge based on a HEI
exposure scenario using two exposure
pathways: air, and ground water. The
national numerical limitations are
established for surface disposal sites
without a liner. The models and
assumptions used in the exposure
pathways to develop the national
numerical pollutant limitations are
similar to those used to derive the
monofill limitations, with certain
modifications described below. EPA
believes such an approach is reasonable
in view of the similarities in likely
environmental effects between disposal
of sewage sludge disposed of on surface
sites and in monofills.
The Agency also evaluated, using the
aggregate risk assessment, a second set
of national numerical limits for "lined"
surface disposal practices. The Agency
determined that national numerical
limits for "lined" surface disposal sites
including monofills were unnecessary
because the aggregate risk assessment
showed very low baseline risk from
current sludge surface disposal methods
and the exposure-based national
pollutant limits for "lined" practices far
exceeded pollutant concentrations
found in sewage sludge from the NSSS.
The Agency concluded from its
evaluation that "lined" surface disposal
practices provide more than an adequate
level of public health and
environmental protection, even in the
absence of national numerical limits.
The second tier applies to "unlined"
surface disposal sites receiving sewage
sludge that contains any pollutant that
violates the national numerical
limitations established for the first tier.
In addition, the second tier also applies
to those "unlined" sites where the
sewage sludge is disposed within 150
meters of the property line. For those
surface disposal sites, the owner or
operator of the site or treatment works
(if different from that of the surface
disposal site), would submit site-
specific data to EPA to use in
calculating alternative pollutant
concentrations for that particular site.
The owner or operator (or applicant)
will use the same exposure pathways
and EPA approved models to calculate
alternative pollutant concentrations. A
more detailed discussion of the second
tier is presented below in the monofill
section of this part.
The two exposure pathways modeled
by the Agency for evaluating national
pollutant limitations or to be used by
the applicant to calculate alternative
case-by-case pollutant concentrations
(using site-specific data) for surface
disposal sites are listed below. These
pathways are similar to the
reconstructed Pathways 13 and 14
(Pathways 12A and 12W in the
proposed rule) used for agricultural land
practices and monofills, and they
employ the same mass balance
methodology.
Pathway 13—In exposure Pathway 13,
the Agency evaluated the exposure of an
individual inhaling vapors of any
volatile pollutants that may be in the
sewage sludge disposed at a surface
disposal site. The exposed individual
(HEI) is assumed to be living at the
downwind edge of the site and is
inhaling air, at a rate of 20 cubic meters
per day for 70 years, that has been
contaminated with volatile organic
compounds from sewage sludge
disposed of at the site.
Volatilization rate coefficients for
uncovered cells are calculated with
equations that consider constituent
parameters including the Henry's Law
coefficient, molecular weight and
distribution coefficient. The rate of
contaminant release through
volatilization is estimated separately for
a covered and uncovered surface
-------
9300 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
disposal site. Contaminant loss to the
vapor pathway is diluted into the total
volume of air passing within two meters
over the site during the period of
contaminant release. This box model is
used to determine the expected air
concentrations to which the HEI is
exposed for each unit of concentration
vaporized at the downwind edge of the
site. The allowable lifetime exposure to
each contaminant (based on a risk level
of 1x10 ~4) is then used to back-
calculate the allowable loss rate to the
vapor pathway. This value is then
divided by the fraction of contaminant
vaporized to determine the allowable
pollutant concentration at the site.
Calculation of criteria for surface
disposal sites through this pathway is
similar to the methods described later
for monofills. One difference is that the
equations used to model emissions are
different for surface disposal sites,
reflecting the fact that these facilities
have a liquid surface throughout their
active lifetime. Another difference is
that surface disposal facilities are not
assumed to receive a soil cover. As with
monofills, pollutant contributions are
allocated to different media using a
moss-balance approach. This calculates
the fraction of constituent loss caused
by volatilization, leaching, and
degradation.
Patiiway 14—In exposure Pathway 14,
the Agency evaluated the exposure of
Individuals who would obtain their
drinking water from ground water
contaminated by the surface disposal
site. Numerical pollutant limits for the
ground water pathway are derived for
surface disposal sites with methods
similar to those used for monofills.
Contaminant losses are first
partitioned among the three competing
loss processes: Volatilization, leaching
to ground water, and on-site
contaminant degradation. For surface
disposal sites, the relatively high water
content of the sewage sludge received at
the site results in an increased rate of
seepage from the facility as compared to
that estimated for monofills. Once the
fraction of contaminant lost to leaching
has been determined, the VADOFT
finite element module (a critical fate
and transport model used in assessing
this pathway) is used to estimate flow
and transport through the unsaturated
zone and is linked to a three
dimensional analytical model AT123D
to depict pollutant fate and transport in
the saturated zone. For surface disposal
sites, the linked model considers the
extent to which constituent transport in
the saturated zone is affected by local
mounding of the water table beneath the
site (i.e., increased hydroaulic pressure
within the sludge pile on the water table
below the site). VADOFT accounts for a
number of processes including
advection, dispersion, adsorption, and
degradation. The mass flux into the
saturated zone is used as input to
AT123D which couples this source term
with aquifer characteristics to predict
concentrations. Exposure concentrations
are predicted based on well locations
150 meters or less downgradient of the
site for facilities located over a source of
drinking water. Reference drinking
water criteria are either MCLs or are
based on a risk level of 1x10 ~4 for an
HEI who consumes two liters of water
per day over a 70-year lifetime.
Surface Disposal—Mono/ill Practice
In the part 503 proposal, EPA
evaluated two exposure pathways for
sludge monofills (also referred to as
sludge-only landfills): (1) human
exposure to sludge pollutants that
infiltrate the ground water and are
subsequently ingested from drinking the
water (Pathway 12W); and (2) human
exposure through vaporization of
pollutants from the fill material and
their subsequent inhalation (Pathway
12A). The analysis considered the long-
term exposure that an MEI would
receive from drinking two liters of
ground water per day and from inhaling
20 cubic meters of air per day at the
property boundary of the monofill. The
Agency calculated the combined water
and air exposure to the MEI and
compared the combined exposure to a
MCL, RfC, RfD, or pollutant risk-specific
dose. As described as follows, the
analytical framework for the ground
water model has four components: (1) a
calculation of contaminated leachate
pulse duration, (2) a model of pollutant
behavior and movement in the
unsaturated zone, (3) an evaluation of
metal solubility in ground water, and (4)
a model of pollutant behavior and
movement in the saturated zone.
The analysis begins with assumptions
on the monofill size and fill thickness,
the pollutant concentrations in the
sewage sludge, the pollutant
concentrations in the leachate, and the
net recharge (infiltration) rate. The
duration of time, T (years), over which
the fill releases a metal pollutant to the
unsaturated zone (leachate pulse
duration) is then calculated from the
following factors: the metal
concentration in sewage sludge, CS
(milligrams per kilogram); the sewage
sludge solids content, SS (kilograms per
liter); the fill thickness, D (meters); the
assumed leachate concentration, CL
(milligrams per liter); the ground water
recharge rate, R (meters per year); and
the excess liquid in the original sewage
sludge volume, EL (liters per liter). The
result is:
T = ((CS x SS/CL) - EL) x D/R
The EL term merely adjusts the
recharge water budget for excess water
in the sewage sludge. For degradable
organic pollutants, the above calculation
is modified to account for the rate of
decay within the fill, as described in the
support documents (Reference Nos. 72
and 102).
The above calculation of the leachate
pulse duration assumes that leachate
concentration remains constant over
time until the sewage sludge is
completely depleted of the pollutant,
thereby modeling the leachate pulse as
a mathematical square wave. For any
particular inorganic pollutant, the
leachate concentration is determined by
a solid/liquid partition coefficient and
the concentration CS in the sewage
sludge.
The leachate pulse (i.e., the initial
volume of liquid entering the
unsaturated zone containing the initial
concentrations of pollutants in that
liquid volume from the fill) was then
used in the unsaturated zone model,
CHAIN (Reference No. 112). CHAIN
assumes a steady rate of percolation
through the unsaturated zone and
calculates the concentrations in the
leachate as affected by sorption to the
underlying soil and decay (of organic
pollutants). The effect of sorption is to
reduce peak concentration of the
leachate and to slow its movement
through the soil. For both metals and
organics, sorption to soil is determined
by a solid/liquid partition coefficient.
The effect of decay is to reduce the
overall amount of organic pollutant in
the leachate. For organic compounds,
decay includes the processes of
hydrolysis and anaerobic
biodegradation.
In evaluating exposure to the MEI, in
the proposal, the depth to ground water
is assumed to be zero over Class I
ground water and one meter over Class
II and Class III ground water. CHAIN is
bypassed in assessing exposure to an
MEI for monofills located over Class I
ground water, but it is used for assessing
exposure to an MEI when a monofill is
located over Class II or Class III ground
water.
At the bottom of the unsaturated zone,
the peak concentrations of metals in the
leachate pulse, attenuated as calculated
by CHAIN (where applicable), are then
adjusted for solubility constraints, based
on the calculations of MINTEQ.
MINTEQ is a computer model which
calculates the fraction of metals
remaining in solution, and the fraction
of metals precipitating out of solution
-------
Federal Register / Vol. 58, No, 32 / Friday, February 19, 1993 / Rules and Regulations 9301
and attaching to the aquifer-rock matrix
(Reference No. 20). The CHAIN model
does not actually operate the MINTEQ
model but rather, in an iterative manner,
uses the results of previous MINTEQ
calculations at various conditions of pH
and Eh to calculate pollutant
concentrations in the aquifer. The
MINTEQ solubility adjustments are
applied only to the six metals (arsenic,
cadmium, copper, lead, mercury, and
nickel). At the low pH and high Eh used
in the proposed exposure assessment
analysis, MINTEQ predicted that copper
would be the only metal to precipitate
in amounts that would reduce greatly
the ground water concentration.
The flux of pollutants entering the
aquifer in the area beneath the monofill
was then input as a square wave (i.e.,
the entire pollutant mass or flux
entering the aquifer enters it all at the
same concentration) at the peak
concentration to the saturated zone fate
and transport model, AT123D
(Reference No. 117). This model
calculates the behavior and movement
of the contaminant plume, as affected by
advection (ground water flow), diffusion
and dispersion (mixing), sorption,
decay, and distance from the sewage
sludge unit to the property boundary of
the monofill or 150 meters (whichever
is less). For Class II and Class III ground
water, the MCL must be met at the
property boundary of the monofill or
150 meters, whichever is less. The effect
of diffusion and dispersion is to spread
the pollutant plume vertically and
horizontally, thereby further reducing
the peak concentration. AT123D was
only operated for Class II and Class III
aquifers, since in Class I aquifers the
leachate must meet the MCL upon entry
to the aquifer.
The components of the model
(leachate pulse—CHAIN—MINTEQ—
AT123D) were operated in an iterative
trial-and-error mode to determine the
sewage sludge concentration that
produced a peak concentration equal to
the MCL at the point of compliance.
The Agency evaluated exposure to
pollutant vapors even though dewatered
municipal sewage sludge is unlikely to
contain significant quantities of highly
volatile material. Most volatile
pollutants would vaporize before
sewage sludge disposal, particularly
during wastewater aeration or during
sewage sludge dewatering. The model
used here (Reference No. 65) has two
key components: (1) Calculation of the
flux of volatile pollutants into the
atmosphere, and (2) determination of
the peak air concentration at the
property boundary.
The model is formulated so that the
vaporization flux depends on the initial
concentration of a pollutant in the
sewage sludge and on the monofilPs
cover material. During the time the
sewage sludge is assumed to be
uncovered, the rate of vaporization is
controlled by the rate of diffusion into
the air (as opposed to diffusion up
through the sludge). The flux is thus
formulated to depend primarily on the
wind speed and Henry's Law constant
(concentration of the pollutant in air
divided by the concentration of the
pollutant in water at equilibrium).
During the time the monofill is
temporarily or permanently covered, the
rate of vaporization depends on the rate
of diffusion up through air-filled pores
in the cover material. The rate thus
depends primarily on the cover
material's porosity and thickness and on
the Henry's Law constant.
The mean flux from the monofill is
determined by considering the areas of
the monofill expected to be uncovered
and temporarily or permanently covered
at any time. The concentration at the
centerline of a plume downwind of the
monofill depends on the size of the
monofill, the distance to the point of
compliance at the property boundary,
the wind speed, and the degree of
atmospheric mixing. The wind direction
is assumed never to change so that the
MEI always remains in the centerline of
the plume. The predicted vapor
exposure was combined with the
predicted drinking water exposure and
then compared to the exposure allowed
by the MCL, RfD, or risk-specific dose.
Comment: Many commenters
maintained that liners should either be
required for monofills—thus making the
national numerical limitations less
stringent or eliminating them—or that
site-specific numerical limits be
established when physical parameters
(e.g., synthetic liners) at the site differ
from those used in the exposure
assessment pathway. Other commenters
advocated requiring liners and
eliminating the national numerical
limitations.
Response: For many of the same
reasons explained previously (Land
Application—Agricultural Practices),
the Agency revised exposure Pathways
12A and 12W (Pathways 13 and 14 in
the final rule) for calculating numerical
limits for disposal of sewage sludge in
monofills. The reconstructed pathways
make use of improved models and more
realistic modeling assumptions, and
they include a mass balance
methodology to account for partitioning
of pollutants across the pathways. The
Agency believes that these changes
should improve the precision and
accuracy of model outputs (i.e.,
numerical pollutant limits) for these
pathways and satisfy many of the
criticisms received from commenters.
The Agency disagrees that liners
should be required for all monofills.
However, the Agency agrees that
national numerical limitations could be
less stringent or even eliminated for
sludge-only landfills that have liners
provided the exposure pathway and
aggregate risk assessments show that
such pollutant limits are unnecessary to
adequately protect public health and the
environment.
A fundamental regulatory principle
used in developing the proposed rule
was pollution prevention. The Agency
believes that it is more protective and
equitable to prevent sewage sludge
contamination by controlling pollutants
at the source than it is to require clean-
up of the contaminated ground water.
Therefore, controlling the quality of the
sludge being used or disposed of is an
over-riding objective of the rule. By
controlling the source, subsequent
contamination of the ground water from
sludge-only landfills is of less concern.
With this principle in mind, the Agency
decided to calculate the proposed
national numerical concentrations of
pollutants based on the monofill being
unlined. However, for the proposal, the
Agency did not consider whether a liner
would provide such an effective means
of pollution control that national
numerical pollutant limits would
become meaningless as a way of
encouraging pollution prevention
because the numerical limits would far
exceed those pollutant concentrations
ever found in sewage sludge. Sludge-
only landfills having a minimum EPA
liner are just such a case, rendering
national numerical limits ineffective as
a means of encouraging pollution
prevention.
The EPA agrees that owner or
operators (or applicants) of monofills
should have the option to establish
alternative (site-specific) numerical
limits when certain physical and ground
water quality parameters at the site
differ from those used in the exposure
assessment pathway. In the proposal,
alternative numerical limits were
established under three case-by-case
circumstances when the physical
parameters at a monofill site (excluding
all other surface disposal practices)
differed from those used in the exposure
assessment models. The three
circumstances (proposed only for
monofills) were as follows:
Case #1—When a monofill has a
sewage sludge unit that is less than 150
meters from the property boundary of
the monofill, site-specific numerical
limits for the pollutants in the sludge
would be recalculated. The applicant
-------
9302 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
would use the actual distance to the
property boundary as a factor to
estimate the amount of dilution used in
the EPA-approved exposure assessment
model so that numerical limits would
not exceed the human health criteria at
the point of compliance (i.e., the
property boundary).
Case #2—Numerical limits for those
monofills over ground water categorized
as Class 111(2) could be calculated if the
background ground water concentration
of one or more pollutants exceeds the
EPA MCLs, the risk-specific doses
corresponding to an incremental
carcinogenic risk level of IxlO"4, or the
RfDs, as appropriate. For those
pollutants whose background ground
water concentrations did not exceed the
EPA human health criteria, the national
pollutant limits in the proposal applied.
Case #3—If the concentration or one
or more pollutants in the sludge
exceeded the national limits, the owner
or operator could submit documentation
showing that site-specific data, rather
than the parameters used by the Agency
in the model to establish the national
limits, could be used in calculating the
pollutant concentrations for sewage
sludge placed in the monofill. Under the
proposal, the numerical limits would be
recalculated for all pollutants using the
sHo-spocific data that the owner or
operator substituted for the EPA
parameters used in the model.
The proposal allowed site-specific
modeling to derive the numerical
pollutant limits for sewage sludge
disposed of in monofills. This approach
did not preclude the applicant from
incorporating into the model the site's
artificial characteristics (e.g., a synthetic
liner) in addition to its natural
characteristics (e.g., a natural clay liner).
The applicant was thus not prevented
from incorporating the effect that
containment measures would have on
infiltration or recharge flow rates
through the fill material and on the
porosity and pollutant sorption beneath
tho fill. For the proposal, the numerical
limits were thus capable of being
modified to account for the effect of
containment measures such as liners.
Final Action: In order to simplify the
final rule and ease the administrative
burden on the regulated community, the
Agency has broadened the definition of
"surface disposal" to include sludge-
only landfills (also referred to as
monofills) and has developed one set of
national numerical pollutant limitations
for all "unlined" surface disposal
practices.
As discussed earlier in this part,
national numerical pollutant limits were
evaluated for surface disposal sites with
"liners" but were not included in the
final rule because EPA determined that
"lined" surface disposal practices
provide more than an adequate level of
public health and environmental
protection, even in the absence of
national numerical limits, and that such
limits would not encourage pollution
prevention. This revision condenses the
regulations and retains the site-specific
modeling option set forth in the
proposal for monofills for "all unlined"
surface disposal practices meeting
certain criteria (the part 503 proposal
only allowed the site-specific option for
monofills).
In the final rule, EPA used exposure
assessment Pathways 13 and 14 to
establish national numerical limits. If
the physical and ground water quality
parameters at the surface disposal site
differ from those used in the exposure
assessment to derive the national limits,
site-specific numerical limits may be
recalculated for the site. There are two
circumstances in which these site-
specific limits are available:
Case #1—When a surface disposal site
has a sewage sludge unit that is less
than 150 meters from the property
boundary of the site, site-specific
numerical limits for the pollutants in
the sludge may be recalculated. The
applicant can use the actual distance to
the property boundary as a factor to
estimate the amount of dilution used in
the EPA-approved exposure assessment
model so that numerical limits would
not exceed the human health criteria at
the point of compliance (i.e., the
property boundary).
Case #2—If the concentration of one
or more pollutants in the sludge exceeds
the national limits, the owner or
operator can submit documentation
showing that site-specific data (i.e.,
parameters other than the parameters
used by the Agency in the model to
establish the national limits) should be
used in recalculating the pollutant
concentrations for sewage sludge placed
in the surface disposal site. In the final
rule, the numerical limits may be
recalculated for all pollutants using the
site-specific data that the owner or
operator substituted for the EPA
parameters used in the model.
Using an EPA-approved model and
the site-specific parameters, the owner
and operator (or applicant) will
calculate for Agency review and
approval alternative pollutant
concentrations for the surface disposal
site. This approach does not preclude
the applicant from incorporating into
the model the site's artificial
characteristics (e.g., a synthetic liner
that does not meet EPA specified
minimum requirements) in addition to
its natural characteristics (e.g., a natural
clay cover or depth to ground water).
The site-specific numerical limits are
thus capable of being modified to
account for the effect of containment
measures such as liners.
In addition, in the final rule, the
Agency has established one set of
national numerical limitations using
two revised exposure assessment
pathways (Pathways 13 and 14). The
national pollutant limits are established
for all surface disposal practices without
an EPA specified minimum liner
including sludge-only landfills without
a liner. As discussed above, the final
part 503 rule does not require sewage
sludge to meet national numerical
pollutant limits if disposed of in or on
a surface disposal site with an EPA
specified minimum liner. If the sewage
sludge that a treatment works wishes to
place in an unlined surface disposal site
(i.e., a site without the EPA specified
minimum liner) continues to exceed the
national numerical limits or the site-
specific numerical limits calculated for
the site on a case-by-case basis, the
treatment works must either reduce the
concentration of the pollutants through
more stringent local pretreatment limits,
install an EPA specified minimum liner,
or find an alternative way of managing
the sewage sludge. The revised exposure
pathways used in the final rule to
evaluate and develop national
numerical pollutant limits for sludge- •
only landfills (a practice cover under
the definition of "surface disposal") are
as follows:
Pathway 13—The vapor pathway is
designed to protect an HEI living at the
downwind edge of the site and inhaling
air at a rate of 20 cubic meters per day
for 70 years that has been contaminated
with volatile organic compounds.
Volatilization rate coefficients for
uncovered or covered landfill cells are
calculated with equations that consider
constituent parameters, including the
Henry's Law coefficient, molecular
weight, and distribution coefficient. The
rate of contaminant release through
volatilization is estimated separately for
its covered and uncovered states.
Contaminant loss to the vapor pathway
is diluted to the total volume of air
passing within two meters over the site,
during the period of contaminant
release. This box model is used to
determine the expected air
concentrations to which the HEI is
exposed for each unit of concentration
vaporized. The allowable lifetime
exposure to each contaminant (based on
a risk level of 1x10 ~4) is then used to
back-calculate the allowable loss rate to
the vapor pathway. This value is then
divided by the fraction of contaminant
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9303
vaporized to determine the allowable
concentration at the site.
Pathway 14—As in Pathway 13, the
first step in calculations for this
pathway is to partition contaminant
losses among the three competing loss
processes: volatilization, leaching, and
contaminant degradation. This
calculation requires an estimated first-
order loss coefficient for leaching,
calculated based on an assumed
equilibrium partitioning of pollutant
between adsorbed and dissolved phases
within the monofill, and on an assumed
rate of seepage from the facility. Once
the fraction of pollutant lost to leaching
has been determined, the VADOFT
finite element module is used to
estimate flow and transport through the
unsaturated zone and is linked to a
three-dimensional analytical model
(AT123D) to depict fate and transport in
the saturated zone. VADOFT accounts
for a number of processes including
advection, dispersion, adsorption, and
degradation. The mass flux in the
saturated zone is used as input to
AT123D, which couples this source
term with aquifer characteristics and
chemical properties. Exposure
concentrations are predicted based on
well locations 150 meters or less
downgradient of the site for facilities
located over a source of drinking water.
Reference drinking water criteria are
based on either MCLs or an HEI who
consumes two liters of water per day
and a risk level of 1x10 ~4.
Comments on the Proposed Exposure
Assessment Approach and Risk
Management Issues for Incineration
The Agency used a single exposure
pathway, inhalation of sewage sludge
incinerator emissions, in analyzing
exposure to the MEI for the proposed
rule. In developing the proposal, the
Agency evaluated the inhalation of
sewage sludge incinerator emissions of
arsenic, beryllium, cadmium,
chromium, lead, mercury, nickel, and
total hydrocarbons. Total hydrocarbons
were used as a surrogate for all organic
pollutants.
The Agency performed air quality
modeling to determine allowable
concentrations in sludge that translate
to pollutant emission rates (mass per
unit time) that would not impose undue
risks to an MEI in the vicinity of the
incinerator. In the case of total
hydrocarbons, the allowable emission
rate determined by modeling was the
numerical limit for the purpose of the
proposed standard. For metals, an
allowable sewage sludge concentration
was derived from the allowable
emission rate.
The Agency evaluated the inhalation
of beryllium and mercury during
development of National Emission
Standards for Hazardous Air Pollutants,
which specify allowable emission rates.
For the proposed rule, the Agency took
the NESHAPs values to be the allowable
emission rates of beryllium and mercury
for sludge incinerators.
The analysis of the inhalation of
incinerator emissions employed
atmospheric dispersion modeling to
relate emission rates to ground level
•exposure concentrations. As discussed
below, the allowable emission rate was
determined from (1) the allowable
ambient air quality concentration at
ground level (the risk-specific
concentration), (2) the stack height of
the incinerator and other physical
characteristics of the site, and (3) the
meteorological conditions of the site.
The allowable sewage sludge quality
was then determined by the above
allowable emission rate, the rate of
sludge incineration, and emission
control efficiency.
For the proposal, the allowable
ambient air concentration was set to
correspond to a risk-specific dose for
four carcinogenic metals (arsenic,
cadmium, chromium, and nickel),
assuming that the MEI inhales 20 cubic
meters of air per day and that indoor
and outdoor air concentrations are
essentially equal. Sewage sludge
incinerators were allocated an air-shed
contribution of lead that corresponded
to 25 percent of the National Ambient
Air Quality Standard.
The allowable ambient air
concentration for total hydrocarbons
was based on (1) statistical relationships
between the concentration of total
hydrocarbons and the concentrations of
specific organic pollutants emitted by
the four sewage sludge incinerators that
were tested and (2) the assumed cancer
potency of the specific organic
pollutants. To develop a site-specific
risk-based concentration for total
hydrocarbons in the proposal, the
Agency developed a weighted
carcinogenic potency (referred to as Qi«
or Q*) value for the organic compounds
that were projected to be in the
emissions of a sewage sludge
incinerator. In developing the Q* value,
the Agency multiplied the Q* value of
every carcinogenic organic pollutant
listed, in IRIS by the weighted fraction
of the compound in the emissions of
sewage sludge incinerators. Calculating
a weighted fraction of a compound in
the emission required a two step
process.
First, the Agency determined the
concentration in micrograms per cubic
meter (ug/m3) for the pollutant in the
emissions in one of three ways. If the
compound was measured in the
emissions of a sewage sludge incinerator
during one or more EPA tests, the 95th-
percentile of the measured
concentrations for the compound was
used. In the case of compounds
expected to be present because they are
commonly found in other combustion
emissions (e.g., emissions from
municipal waste combustors or
hazardous waste incinerators) but not
detected, the concentrations of these
compounds in emissions from these
sources (ug/m3) were used. Finally, for
the remaining pollutants listed in IRIS
and not detected in the emissions of
sewage sludge incinerators, an
analytical detection limit of 0.1 ug/m3
was assigned to those pollutants. The
Agency then calculated a weighted
fraction for each pollutant by dividing
the sum of all the pollutant
concentrations into each individual
pollutant concentration. Then the
weighted fraction of each pollutant was
multiplied by the pollutant's cancer
potency value (Q*) and the resulting
product was summed to give ;a weighted
carcinogenic potency value for all
carcinogenic pollutants detected or not
detected.
Weighted fractions were also
calculated for all non-carcinogens that
have a reference dose in IRIS. However,
the Agency assumed that the actual
ambient air concentration of the non-
carcinogens (i.e., threshold pollutants)
would not exceed their inhalation RfDs
and, therefore, do not contribute to the
weighted Q* value or cause adverse
health effects. The weighted Q* value
was calculated as 0.013 (milligrams per
kilogram per day) ~'.
From the Q* value, the Agency
developed a risk-based concentration
(RSC) for THC of 2.69 ug/m3 used in the
proposal. This value represents the
lifetime average exposure to THC that
would yield a risk of 1x10 ~'5 for the
most exposed individual. The proposal
used the RSC in a simple equation to
develop a site-specific numerical limit
for the maximum allowable THC
concentration in the facilities
incinerator emissions. This calculated
numerical limit is compared to the
oxygen-corrected total hydrocarbon
reading from the flame ionization
detector to determine if the incinerator
would be in compliance with the
facility's permit.
Three models were used in the
proposal for incineration to derive
emission dispersion factors: ISCLT,
LONGZ, and COMPLEX I (Reference No.
74). ISCLT is intended for urban or rural
situations where the terrain elevations
do not exceed the stack height. It
-------
9304 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
considers the aerodynamic effect of
building downwash, which is likely to
ba significant for many sewage sludge
incinerators with short stacks. The other
two models do not evaluate building
downwash but are more appropriate in
situations where terrain elevations
exceed the stack height. Such terrain is
termed complex terrain. LONGZ is
intended for complex urban terrain,
while COMPLEX I is intended for
complex rural terrain.
AH three models require data on the
incinerator, the surrounding terrain, and
the meteorology of the site where the
incinerator is located. Incinerator data
included stack height, stack exit
diameter, gas flow, and gas temperature.
Meteorological data included joint
frequency distributions of wind
direction, wind speed, and atmospheric
stability. The location of the MEI was
not specified beforehand, but it was set
at the location predicted by the model
to have the highest long-term average
ground level concentration.
In assessing the exposure to the MEI,
1SCLT was used because of its ability to
simulate building downwash. Since the
MEI location for facilities with
significant downwash tends to be close
to the incinerator, the inability to
simulate complex terrain accurately was
not considered a serious shortcoming.
Sido-by-side comparisons of the three
models indicated that, where downwash
is significant, ISCLT predicts higher
concentrations than LONGZ or
COMPLEX I, even in complex terrain.
Evaluation of the effect of model
parameters on the results indicated that
stack height was a key parameter.
Consequently, the Agency found that
the dispersion factor (maximum long-
term exposure concentration per unit
rate of emission) varies with stack
height. By modeling a number of
facilities having various stack heights,
the Agency was able to generate a
correlation between dispersion factor
and stack height. Although the stack
diameter and gas velocity also varied
among these facilities, these parameters
were not important and had little effect
on the correlation. Other parameters
wore hold constant and were applied to
all facilities: wind characteristics of
Atlanta, Georgia (which had the worst
combination of parameters in any U.S.
city examined); flat terrain; gas
temperature (38 degrees Celsius);
building height (5.5 meters); and
building effective diameter (39.5 meters)
(Reference No. 45). The results of this
analysis were presented in Table 9 of
the proposal, which correlated stack
heights to national dispersion factors for
use in establishing numerical pollutant
limits for sewage sludge incinerators
(except in the case where stack height
exceeded 65 meters, the proposal would
have required use of a "good
engineering practice" height to correlate
to a dispersion factor in Table 9).
The metals emission control
efficiencies assumed in assessing the
exposure to the MEI corresponded to the
worst 10 percent of EPA's data on
sewage sludge incinerators. These
control efficiencies were as follows:
arsenic, 96 percent; beryllium, 99
percent; cadmium, 65 percent;
chromium, 96 percent; lead, 67 percent;
mercury, 0 percent; and nickel, 95
percent. Control efficiencies were not
assumed for organic compounds.
Instead, total hydrocarbons were used to
control organic emissions.
The Agency proposed a THC
operational standard of 20 ppm as one
of several options it was considering for
regulating sewage sludge incinerators in
the November 9,1990, notice of the
NSSS. At the time, the Agency
concluded that the 20 ppm THC option
was acceptable for sewage sludge
incinerators because it was consistent
with the 20 ppm THC standard used for
hazardous waste incinerators and was
within the operating range for
incinerators tested by the Agency.
Because the Agency had only tested 9
sewage sludge incinerators and was
basing its THC standard for sludge
incinerators on incinerators designed to
fire hazardous waste, EPA requested
comment on what level the operational
standard for THC should be set (i.e., 10
ppm, 20 ppm, 30 ppm, etc.).
Comments: The Agency received
numerous comments on the exposure
assessment approach used to establish
numerical pollutant limitations for
sewage sludge incinerators. Many
commenters argued that EPA lacked
adequate data on the scientific basis for
Establishing metals emission control
efficiencies for sewage sludge
incinerators. Commenters further stated
that selecting the worst 10 percent
(lOth-percentile) from such limited data
lacked adequate justification and was an
arbitrary decision on the Agency's part.
In addition, many commenters were
critical of EPA's table of national air
dispersion factors. The commenters
cited the Agency's use of an outdated
ISCLT model and inappropriate or
overconservative modeling assumptions
as the major problems with the analysis
used to develop the dispersion factors.
Several commenters felt that the table of
dispersion factors was unnecessary and
that the Agency should require site-
specific modeling using Clean Air Act
procedures to determine the air
dispersion factor for a sewage sludge
incinerator.
Several commenters (including the
Agency's Science Advisory Board and
other scientific review) took issue with
the methodology used to establish THC
limitations contending that too many
scientific uncertainties exist in the
calculation of a single weighted
carcinogenic potency value representing
the risk of organic compounds emitted
from sewage sludge incinerators. Other
commenters opposed certain other
aspects of the Agency's proposed
method for calculating hydrocarbon
limitations, including assigning a
detection limit of 0.1 ng/m3 for both
carcinogens and threshold compounds
not detected in any of the incinerators
tested by EPA but included in EPA's
IRIS data base. Many commenters
pointed out that the correlation between
THC readings and the total
concentration of detected organics in
the four incinerators EPA tested was
poor and that EPA should conduct more
testing before it tries to calculate a risk
for total hydrocarbon emissions.
Commenters supported a single
operational standard for THC emitted
from sewage sludge incinerators but
questioned EPA's proposed 20 ppm
THC standard as being unrealistically
low and outside the normal operating
range for existing sludge incinerators.
Response: The Agency has concluded
that it is infeasible to establish a risk-
based numerical pollutant limits for
THC emissions from sewage sludge
incinerators and that it should adopt an
operational standard for total
hydrocarbon emissions. The
uncertainties identified by the Agency's
SAB and commenters have convinced
the Agency that site-specific, risk-
related THC emission limits cannot be
technically supported.
hi addition, with respect to metal
control limits, the Agency agrees that
adequate data on sewage sludge
incinerators are not available to
establish national metals emission
control efficiencies, and that its
simplified air model (an outdated ISCLT
model) and assumptions were not
adequate to develop national air
dispersion factors for sewage sludge
incinerators. Control efficiency refers to
the effectiveness of an incinerator and
its air pollution control system in
preventing the release of metals to the
atmosphere. The air dispersion factor
relates the maximum allowable
emission rate of a pollutant from a
sewage sludge incinerator stack to a
maximum allowable increase in the
ground level ambient air concentration
for that pollutant at a specific distance
from the incinerator. The air dispersion
factor and the combined metal control
efficiencies of the incinerator and the air
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9305
pollution control system are key
variables in calculating safe numerical
limits for pollutants in sewage sludge
destined for incineration.
In the part 503 proposal, the Agency
established metals emission control
efficiencies and air dispersion factors to
provide owners and operators of sewage
sludge incinerators greater flexibility in
complying with the regulations. Under
the proposal, owners and operators had
the option of (1) site-specific testing to
determine the metal emission control
efficiency and the air dispersion factor
for the incinerator or (2) using the
control efficiency and dispersion factor
established by the Agency to calculate
the maximum allowable concentrations
of pollutants in the sewage sludge to be
incinerated.
Further, the Agency agrees with many
of the comments provided by the public
and the scientific peer review
committees concerning the limitations
of its approach for establishing site-
specific THC limitations for sewage
sludge incinerators, and that an
operational standard(s) for THC is more
appropriate given data and scientific
limitations. In the part 503 proposal, the
Agency proposed to establish site-
specific numerical limitations for THCs
and required continuous monitoring of
THC as a technique for controlling toxic
organic emissions from sewage sludge
incinerators. Total hydrocarbons were
used as a surrogate for organic
pollutants emitted from sewage sludge
incinerators. The Agency proposed
limiting the concentration of total
hydrocarbons in the emissions in lieu of
specifying the concentration of organic
pollutants in sewage sludge that may be
fed into the incinerator. The Agency
performed air quality modeling to
determine the emission rates for organic
pollutants (as measured by THC) and
inorganic pollutants that can be allowed
without imposing undue risks to the
most exposed individual in the vicinity
of the incinerator. As discussed above,
for organic pollutants the allowable
emission rate determined by modeling
is the numerical limit for THC
emissions from sewage sludge
incinerators. This is not the case for
inorganic pollutants or metals, where
the allowable emission rate was used to
derive a safe inorganic pollutant
concentration in the sewage sludge on a
pollutant-by-pollutant basis.
EPA had originally considered
controlling the concentration of organic
pollutants fed into an incinerator on a
pollutant-by-pollutant basis, similar to
the approach proposed for metals.
However, the approach was not feasible
for organic pollutants because the
Agency could not establish a
destruction and removal efficiency
(DRE) for sewage sludge incinerators.
DREs of an incinerator are needed to
relate the emission of an organic
pollutant to its risk-specific
concentration and to an allowable safe
concentration of organic pollutant in the
sewage sludge to be incinerated.
EPA proposed to limit the
concentration of total hydrocarbons in
the emissions of sewage sludge
incinerators for two reasons. First, the
approach controls the emission of
individual organic compounds found in
sludge fed into the incinerator; and
second, the approach controls the
emission of organic compounds that are
created during the combustion process
(i.e., products of incomplete
combustion, PICs). The Agency
recognized setting limitations on total
hydrocarbons was an innovative
approach that might stimulate
considerable scientific debate as to its
use in the proposed rule and to its
applicability to other Agency
incinerator programs.
Final Action: The Agency agrees with
many of the findings and
recommendations made during
scientific review of the proposal and
public comment period. As a result, the
Agency has used an updated ISCLT
model for exposure evaluations for the
four carcinogenic metals and lead, and
has revised its approach for determining
air dispersion factors, control
efficiencies for inorganic pollutants (i.e.,
metals) and its THC approach for
controlling organic pollutant emissions
from sewage sludge incinerators. The
Agency has not established air
dispersion factors and metal control
efficiencies for sewage sludge
incinerators because it currently lacks
adequate data to establish dispersion
factors and control efficiencies on a
national basis. However, in the final
rule the Agency has required owners
and operators of sewage sludge
incinerators to conduct site-specific
modeling and performance tests of their
facilities to calculate the air dispersion
factor and the control efficiency with
which the incinerators and air pollution
control systems control the emissions of
one or more of the pollutants listed in
the final rule. The Agency has
determined that the updated ISCLT
model is the preferred air dispersion
model for evaluating pollutants of
concern for the final rule, and that the
dispersion factor modeling and
emission control tests are to be
conducted using models and procedures
specified by the permitting authority
with jurisdiction over the incinerator.
In addition, the Agency has replaced
its proposed THC approach with an
operational standard similar (but not
identical) to the technology-based Tier II
approach being used by the Agency for
hazardous waste combustion systems
[40 CFR Parts 260, 261, 264 and 270,
Standards for Emission Monitoring for
Owners and Operators of Hazardous
Waste Incinerators; and 40 CFR Part
260, Burning of Hazardous Wastes in
Boilers and Industrial Furnaces
(Reference Nos. 104 & 95)].
The CWA specifically authorizes
alternatives to establishing numerical
limitations for pollutants in sewage
sludge in certain circumstances. Section
405(d)(3) of the CWA states:
Alternative standards—For purposes of
this subsection, if, in the judgment of the
Administrator, it is not feasible to prescribe
or enforce a numerical limitation for a
pollutant identified under paragraph (2), the
Administrator may instead promulgate a
design, equipment, management practice, or
operational standard, or combination thereof,
which in the Administrator's judgment is
adequate to protect public health and the
environment from any reasonably anticipated
adverse effect of such pollutant.
Congress recognized that
circumstances would arise where it
would not be feasible for EPA to
prescribe numerical limits for pollutants
in sewage sludge for certain sewage
sludge use and disposal practices. Since
a scientifically defensible methodology
currently does not exist that can
accurately link the concentration of
organic pollutants in sewage sludge to
organic pollutants emitted from the
stack of a sewage sludge incinerator,
EPA has concluded that establishing
"site-specific" organic pollutant limits
for sewage sludge incinerators is just
such a case. Thus, for the final rule, the
Agency has established a national
operational standard for THC emissions
of 100 ppm (measured as a monthly
average) to ensure that good operating
practices at sewage sludge incinerators
achieve an adequate level of public
health and environmental protection.
EPA has selected a regulatory limit of
100 ppm THC (measured on a monthly
average—corrected to 7 percent oxygen)
for sewage sludge incinerators because:
(1) it is within the range of values
reported in our data base for
incinerators burning sewage sludge; (2)
the monthly average excursion policy
ensures good operating practice at
sludge incinerators on a continuous
basis; and (3) the aggregate risk
assessment for this practice showed low
"baseline" risk to the HEI and the
population as a whole.
The final part 503 approach requires
owners and operators of sewage sludge
incinerators to monitor continuously to
ensure that the THC level does not
-------
9306 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
oxcood a good operating practice-based
THC limit (i.e., on operational standard
forTHC emissions) of 100 ppm THC. As
discussed later, continuous THC
monitoring is required using a flame
ionizalion detection (FID) system over
the life of the permit.
EPA has adopted an operational
standard of 100 ppm for all sewage
sludge incinerators because it
concluded that all POTWs should
achieve this emission level. Data in the
record clearly establish that fluidized
bod incinerator will have no difficulty
in complying with this standard and
that most multiple hearth units can also
comply. In the case of some multiple
hearth incinerators, POTWs will need to
implement process and "good
engineering practice" controls to meet
tho prescribed limits. Requiring
compliance with the 100 ppm standard
will require some reduction from
current levels of sewage sludge
incinerator emissions but the Agency
cannot estimate how such changes from
current practice might reduce human
exposure.
The aggregate risk assessment shows
that, in the case of organic emissions,
current emissions represented a risk of
0.2 (based on "best estimate" emission
levels) to 4 cancer case (based on 99th-
porcontile "worst case" emission levels)
annually and a risk to a HEI of 4xlO~4
to 7xlO~3. EPA concluded that any
reduction in risk associated with
reducing THC emissions below 100 ppm
could not be justified in terms of
increased protection of public health
and the environment. EPA based this
conclusion on the fact that the risk
assessment for incinerator included very
conservative assumptions. These
assumptions yielded results that the
Agency has concluded probably
overstate the risk associated with
current levels of sewage sludge
incinerator organic emissions.
Tho risk assessment numbers are
based on estimations of organic
emissions from sewage sludge
incinerators. In order to develop these
estimations, a number of very
conservative assumptions were made for
both the best estimate and worst case
scenarios, that probably results in
overstating THC emissions for purposes
of this analysis. These include assuming
that all organic compounds that were
sampled and analyzed for at seven
sowago sludge incinerators—the organic
compounds included in the Agency's
risk assessment data base, IRIS—are
present in the organic emissions of 172
POTW incinerators. In fact, the data
establish that many of these compounds
(including aldrin/dieldrin and
hoxachlorobenzene) were not detected
at all in the samples. Fifty one percent
of the calculated aggregate risk is based
on risk associated with three
compounds, not found in the sewage
sludge samples and that will not be
created in the process of combustion.
Furthermore, organic compounds not
detected in the sampling at
concentrations below the detection
limits were assigned emission levels
that corresponded to the detection limit
concentrations. This overstates THC
emissions because the true level is
below the detection limit and may be
significantly lower or non-existent.
Moreover, organic compounds that were
not detected in the samples were still
assumed to be emitted by an incinerator.
The emission level assigned for these
compounds is either the detection limit
value or average values based on
detection limits for other compounds.
Again, this represents an assumption
that results in overstatement of the level
of risk.
After calculating risk associated with
sewage sludge incinerator emission for
THC using the assumptions discussed
above, for its "worst-case" scenario, the
aggregate assessment increased these
estimates by a factor of 5 to account for
organic emissions from the stack that
have not been identified or quantified.
This was done on the assumption that
there are unidentified and unquantified
organic emissions from sludge
incinerators. EPA, in its recent report to
Congress on municipal waste
combustion concluded that a significant
portion of organics emissions (80
percent or more) have not been
identified and quantified. However, the
report went on to explain that the
portion of the mixture that is
carcinogenic and its potency is not
known. (The Municipal Waste
Combustion Study Report to Congress
(U.S. EPA 1987a).) Consequently,
increasing the risk calculations by a
factor of five overstates risk to the extent
that the unaccounted for and
unquantified portion of the emissions'
stream does not include carcinogenic
organics.
In light of this and the fact that over
half the calculated risk is associated
with compounds not detected in sewage
sludge, EPA determined that there is no
basis for limiting emissions to a level
below 100 ppm. As previously
explained, EPA considered requiring
sewage sludge incinerators to achieve a
20 ppm emission level. However, the
Agency had not considered how much
variability (i.e., excursions above the
THC standard) it would allow in
measuring THC emissions from sewage
sludge incinerators for purposes of
compliance. Obviously, requiring a 20
ppm THC operational standard on a
quarterly or yearly basis is significantly
different from enforcing the same
standard on a daily or monthly basis.
For example, if the Agency used a
yearly average as its excursion policy for
enforcing the 20 ppm THC standard,
emissions from sewage sludge
incinerators could be significantly above
the THC standard for periods up to six
months.
However, the Agency has decided to
adopt a monthly averaging period for
the purpose of determining compliance.
If the Agency enforced the 20 ppm THC
standard on a monthly basis, such a
policy would be over protective given
the "baseline" aggregate risks associated
with sewage sludge incinerators, and
many sludge incinerators would be out
of compliance (even though 20 ppm is
within their operating range) because
they are unable to consistently achieve
that level of operation on a monthly
basis. Data reviewed by the Agency
established that many sewage sludge
incinerators have greater variability in
their THC emissions than do other
waste incinerators because sewage
sludge, in general, has a high moisture
content and that moisture content can
vary widely during operation.
Other Risk Management Issues,
Comments, Responses and Final Action
A number of comments were received
from commenters that are specific to
various risk management aspects of the
part 503 regulations. A synopsis of the
major comments and the Agency's
responses and final actions is given
here. More comments and responses on
these and other topics may be found in
the Response to Comments Document
for the Proposed part 503 rule
(Reference No. 109). Information on
obtaining single copies of this document
is provided in part XIV of the preamble.
Domestic Septage
Comments on the Proposed Approach
The Agency received over 130
comments concerning the proposed
treatment of septage. A majority of the
commenters opposed the regulation of
septage as sewage sludge. Commenters
indicated the proposed regulations were
too costly to implement and would have
a negative effect on the environment.
The commenters maintained that the
regulations, if adopted as proposed,
could eliminate the land application of
septage or could cause illegal or reduced
pumping of septage systems by
homeowners or illegal dumping.
Many comments were received from
small communities and septage
pumpers and haulers disagreeing with
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9307
the Agency's proposed approach. They
argued that applying the proposed
regulations for sewage sludge from
POTWs to domestic septage collected
from private homes was over stringent,
burdensome, and would have little or
no environmental benefit. They were
particularly concerned about the
proposed requirements for pathogen and
vector attraction reduction, and the
frequency of monitoring pollutants,
recordkeeping and reporting.
Response to Comments
The Agency, after reviewing the
public comments, agrees that the
regulations as proposed, if applied to
septage, would have been exceedingly
difficult to implement and therefore,
unlikely to achieve the public health
and environmental statutory objectives.
The proposed part 503 rule regulated
septage that is pumped and collected for
use or disposal (septic tank pumpings)
in the same manner as municipal
wastewater sewage sludge. Even though
a comprehensive national data base on
septage quality did not exist at the time
of the proposal, EPA believed that
septage, like sewage sludge, had the
potential to adversely impact public
health and the environment because
septage was suspected of having very
similar properties to sewage sludge and
containing the same types of pollutants
and pathogenic organisms. Moreover,
the legislative history of section 405
evidences Congressional intent that
EPA's regulations should address
domestic septage as well as sewage
sludge. S. Rep. No. 50, 99th Cong., 1st
Sess., p. 47 (1985). It was for these
reasons that EPA decided to regulate
septage in the part 503 proposal.
Under the proposed approach, the
same numerical pollutant limits and
management practices applicable to
sewage sludge would have also applied
to septage. In addition, septage would
have been required to be analyzed to
determine the amount and presence of
inorganic and organic pollutants
covered by the regulations. This
information was required to allow the
septage pumper or hauler to determine
the appropriate use or disposal practice.
If, as is generally the case, septage is to
be applied to agricultural or non-
agricultural land, pollutant
concentration data would be needed to
determine the allowable pollutant
application rate or maximum pollutant
concentrations for applying the septage
to the land. EPA believed that
concentrations of inorganic and organic
pollutants in septage would be lower
than concentrations of these pollutants
in sewage sludge because of the
septage's predominately domestic
sewage nature and the lack of significant
industrial wastewater contribution to it.
Because septage quality should be better
than sewage sludge quality, the Agency
believed that it would prove easier for
septage than for sewage sludge to
comply with the requirements of the
part 503 proposal.
Because of the comments and
information EPA received on the
proposal, the Agency evaluated
alternative regulatory strategies that
would similarly protect public health
and the environment but are less
complex and easier to implement. One
such strategy was put forth in the 1990
notice of the NSSS (55 PR 47240-47242,
November 9,1990). This approach
replaced pollutant monitoring and
cumulative pollutant loading limits
used for sewage sludge with a single
hydraulic loading rate (30,000 gallons
per acre per year) for septage applied to
the land. In addition, the approach used
short term lime stabilization to control
pathogens and vector attraction, and
other requirements such as crop, use
and access restrictions to ensure
adequate protection of public health and
the environment. This approach
received many favorable comments from
reviewers.
The Agency recognized, as a result of
comments on the proposal and 1990
notice, that several factors must be taken
into account when regulating septage.
Most septage collection businesses are
small operations, usually three or fewer
trucks. Each truck generally has a
storage capacity of about 2,000 gallons
which will contain the wastewater from,
at most, two typical home septic tanks.
Under these circumstances, it is readily
apparent how difficult it would be to
require sampling and testing of septage
for organics, metals and nitrogen, and
then regulate land application based on
septage quality. Such an approach
appears particularly onerous for small
and marginal businesses in the septage
service industry.
While the Agency believes domestic
septage has many of the same chemical
and biological constituents as sewage
sludge and septage requirements must
protect public health and the
environment to the same degree as
sewage sludge requirements, it has also
concluded that septage presents less of
a risk to public health and the
environment than sludge may because
these constituents are found at very low
concentrations. Presently, a number of
States and local governments regulate
land application of septage by
controlling the amount of septage that
may be applied on a gallons per acre per
year basis—a hydraulic loading rate
approach similar to the approach
considered in the 1990 notice.
The Agency believes the use of a
hydraulic loading rate is an attractive
alternative for small volumes of septage
with low levels of pollutants. Such a
regulatory approach is easily
understood and implemented by small
communities and septage pumpers and
haulers. Moreover, it does not require
specific testing of septage loads and
land application based on the analysis
of septage quality. This approach also
lends itself to a simple recordkeeping
system. Regulatory agencies would
merely check the haulers' records which
would indicate the gallons of septage
hauled to a specific site.
To validate the hydraulic loading rate
approach for the final rule, the Agency,
using data on domestic septage quality,
compared calculated reasonable
hydraulic loading rates for septage to
the risk-based pollutant loading rates for
sewage sludge. The first step was to
calculate reasonable hydraulic loading
rates based on the nitrogen requirements
of various crops and vegetation
expected to be grown on land
application sites. Based on the available
nitrogen content from domestic septage
and varying the crop uptake rate in
pounds of nitrogen per acre per year, a
range of annual septage application
rates were calculated as a function of
crop nitrogen requirements.
Determining the annual septage
application rate based on nitrogen
uptake was considered reasonable
because it provides only the amount of
nitrogen needed to satisfy the growth
requirements of crops and vegetation
grown on the land application site.
To verify that hydraulic loading rates
for domestic septage protect public
health and the environment, the Agency
reviewed the pollutant content of
domestic septage from data gathered
during the public comment period
(Reference number 107). Using this
information, the Agency calculated the
cumulative pollutant loads for each
pollutant in domestic septage and
compared them to the risk-based
cumulative pollutant loads developed
for the land application of sewage
sludge in the final part 503 rule. Based
on this analysis the Agency concluded
that a hydraulic loading rate approach
for septage applied to land would
provide a similar level of public health
and environmental protection as
cumulative pollutant loading limits
provide for sewage sludge.
The Agency also evaluated the
adequacy of site restrictions and pH
controls as a means of protecting public
health and the environment from
pathogens found in and vector attraction
-------
9308 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
to domestic septage. Domestic septage
contains pathogens and is capable of
attracting vectors when untreated
septage is applied to the land surface.
Based on a university study (Ronner,
A.B., Cliver, D.0.1987. "Disinfection of
Viruses in Septic Tank and Holding
Tank Waste by Calcium Hydroxide."
University of Wisconsin, Madison) and
on several States' experience with lime
stabilized septage, the Agency found
that raising the pH of septage with an
alkaline material to 12 or above for 30
minutes stabilizes domestic septage and
equals the minimum pathogen
reduction requirements for a Class B
sowaga sludge described in the part 503
proposal. In addition, the Agency found
that (based on States' experience) the
vector attraction reduction requirement
for soptage is also satisfied by pH
control because odors ore drastically
reduced.
Site use and access restrictions were
also evaluated as a way of protecting
public health and the environment
when pH control was not used to reduce
pathogens and vector attraction to land
applied septage. The Agency
determined that use and access
restrictions were an appropriate means
of protecting public health and the
environment in the absence of pH
control by ensuring that exposure to
untreated septage is minimized. Thus,
for tho final rule, the Agency concluded
that either pH control or use and access
restrictions would provide an adequate
luvol of public health and
environmental protection from land
applying domestic septage.
In addition to the above changes, the
Agency simplified many of the
monitoring, recordkeeping, and
reporting requirements for domestic
septage. EPA believes that these changes
result in domestic septage requirements
for the final part 503 rule that are more
implomentable than the requirements in
the proposal, and that protect public
health and the environment from
reasonably anticipated adverse effects of
pollutants found in domestic septage.
Final Action
As a result of public comments, the
Agency has revised its approach for
regulating domestic septage applied to
land or surface disposed for inclusion in
tho final part 503 rule. It is the Agency's
conclusion that the revised approach
will bo loss burdensome and still protect
public health and the environment. The
requirements in today's final rule apply
only to domestic septage as defined and
not to sewage sludge. These
requirements also do not apply to
domestic septage that is co-mingled
with industrial or commercial
wastewaters, sludges or greases. A
description of the requirements for the
final part 503 rule is provided below:
1. Domestic septage land application
rate limit. The rate of septage applied to
land would be limited to an annual
septage application rate (gallons per
acre per year—hydraulic loading rate)
depending on the crops or vegetation
grown on the land application site. The
Agency has determined that limiting the
hydraulic loading of septage, based on
the nitrogen requirements of crops and
vegetation, will adequately protect
public health and the environment. This
approach, based on the data on
pollutant concentrations in septage
reviewed by the Agency, ensures that
the application of septage will not result
in exceeding the cumulative pollutant
loadings for metals that the Agency has
found to be protective. In addition,
septage applied at the appropriate
hydraulic loading rate will satisfy
nitrogen demands for growing crops
without adversely affecting surface or
ground water because available
inorganic nitrogen will be taken up by
the crops and organic nitrogen will be
released too slowly (over a period of
years) to cause contamination of surface
or ground waters.
In contrast to land application, when
domestic septage is disposed of on a
surface disposal site, the final rule does
not limit the application of septage by
a hydraulic loading rate. Based on its
review of data on metal concentrations
in septage, the Agency has determined
that a loading limitation is not required
to protect public health and the
environment. Metal concentrations in
septage are well below safe numerical
pollutant limits for sewage sludge when
disposed at a surface disposal site.
Moreover, the volume of domestic
septage being disposed is small in
comparison to sewage sludge.
2. Pathogen and vector attraction
reduction. Short term alkaline
stabilization (pH adjustment) is required
to reduce pathogens and vector
attraction prior to land application of
septage. Short term stabilization with
lime or equivalent alkaline products
would be accomplished by raising the
pH of septage to 12 or greater for 30
minutes. When domestic septage is
disposed of at a surface disposal site,
alkaline stabilization is required if the
surface disposal site does not inject or
incorporate the septage into the soil, or
cover the septage by the end of the
operating day. These requirements are
similar (but not identical) to the
pathogen and vector attraction
reduction Criteria for Classification of
Solid Waste Disposal Facilities (40 CFR
part 257). The Agency has concluded
that raising the pH of domestic septage
reduces pathogens, indicator organisms
and vector attraction and thereby
decreases the risk of disease to the
public. In cases where alkaline
stabilization is not possible, restrictions
on crops, use and access are required to
protect public health and the
environment.
3. Crop restrictions. When alkaline
stabilization is not possible and
domestic septage is applied to
agricultural land, the planting of crops
whose edible portions may contact the
surface soil and of root crops grown in
the soil would be prohibited after
septage application for 14 and 38
months, respectively. The Agency has
found that short term alkaline
stabilization does not sterilize the
septage but does significantly reduce the
number of pathogens and indicator
organisms. The 14 and 38 month
planting delay would allow further die-
off of these organisms from exposure to
sunlight and frequent drying to levels
the Agency believes is protective of
public health.
4. Use and access restrictions. When
alkaline stabilization is not possible,
access to sites where the potential for
public exposure is high (e.g., parks and
recreational areas) is restricted for 12
months after application of domestic
septage to those sites. This is the same
period in the current Criteria for
Classification of Solid Waste Disposal
Facilities (40 CFR part 257) for septage
that is applied to the land if the septage
is not treated in a Process to
Significantly Reduce Pathogens. The
main purpose of the 12 month
restriction is to protect children who
may ingest septage-amended soil while
playing in the areas where domestic
septage is applied. The Agency believes
that the 12 month period is reasonable
based on pathogen die-off information
for septage-amended soil. For
agricultural and non-agricultural lands
(i.e., forest and reclamation sites) where
the potential for exposure to the
septage-soil mixture is low, public
access would be restricted for 30 days.
In addition, animals will not be allowed
to graze or feed crops harvested for a
period of 30 days after the application
of septage. EPA concluded that the use
of different time periods for access
restrictions is appropriate because those
time periods reflect the potential for
different exposures. The Agency also
believes, based on available
information, that the different time
periods help protect the public from the
effects of pathogens in domestic septage.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9309
Site-Specificity for Use and Disposal
Practices
Comments on the Proposed Approach
Many commenters maintained that
the part 503 rule should provide greater
flexibility in establishing numerical
pollutant limitations and management
practices for sewage sludge use and
disposal by allowing for variances based
on site, state or regional specific factors.
The commenters argued that since site-
specificity is currently a basis for EPA's
National Pollutant Discharge
Elimination System (NPDES) permitting
program under the Clean Water Act and
the part 503 regulations are an extension
of this program, the same type of site-
specific evaluation should be allowed
for sewage sludge use and disposal.
Treatment works or individuals using or
disposing of sewage sludge would then
have the option of complying with the
national standards, or requesting a
variance or waiver based on meeting
state design standards or site-specific
conditions. The commenters believed
that this approach would increase the
beneficial reuse of sewage sludge but
recognized it would also increase the
burden on the permitting authority. One
commenter suggested that EPA allow
site-specific soil testing for metals once
cumulative inorganic pollutant
limitations are reached in order to
determine if the site-life for agricultural
land practices is actually exhausted.
Another commenter felt that the
monofill model should be modified, on
a case-by-case basis, to remove that
quantity of pollutant taken up by plants
and animals on the site from the
quantity of pollutants available for
leaching to the ground water.
Response to Comments
The Agency agrees that the part 503
regulations, to the extent feasible, given
limited Agency resources, should
provide the flexibility to modify the
standards in appropriate circumstances.
In the part 503 rule, the Agency used
pollutant fate and transport models in
14 exposure assessment pathways to
predict the long-term human health and
environmental effects of using or
disposing of sewage sludge by the
practices covered in the regulations.
Sensitivity analyses were performed on
the models to identify those factors that
were most significant in determining the
model results. In conducting the
sensitivity analyses for the proposal, the
Agency found for certain disposal
practices that varying certain parameters
made a significant difference in a
numerical limit for a pollutant, without
causing the pollutant to exceed the
human health or environmental
endpoint from which the limit is
calculated. However, the Agency did
not find any physical parameters in the
land application model made a
significant difference in the pollutant
limits.
For the proposal, the Agency also
considered developing a "tiered"
regulatory approach for treatment works
that could not meet the national
numerical limits and did not want to
conduct site-specific exposure
assessment modeling for all the
parameters in the 14 exposure
pathways. Such an approach would
establish intermediate numerical limits
based on varying a few pathways and
parameters at each tier. Treatment
works would submit for the appropriate
tier their site-specific numerical limits,
exposure pathway assessment and
supporting data to the permitting
authority, and the permitting authority
would review and approve the data,
exposure assessment and site-specific
limits.
One reason the Agency rejected the
"tiered" regulatory approach was its
complexity. Such an approach would be
inconsistent with the Agency's principle
of developing a rule that could be
implemented easily (i.e., a self-
implementing rule). It would be
impossible to include in the rule all
possible variations occuring at a site.
Another reason for rejecting the
approach was that the Agency did not
believe that treatment works would use
the intermediate tiers. Rather than
varying only a single parameter, the
Agency felt it more likely that a
treatment works would collect data on
as many parameters as possible to
determine if, by doing so, their sludge
could meet recalculated numerical
limits for their site. This would further
complicate implementation of the rule,
increase the burden on the permitting
authority and the treatment works, and
based on the Agency's analysis for the
proposal, provide no significant
difference in the pollutant limits for
land application practices.
For the final part 503 rule, the Agency
reexamined whether or not to allow site-
specific pollutant limits for land
application practices beneficially using
sewage sludge as a fertilizer or soil
amendment. As discussed above, EPA
evaluated 14 exposure assessment
pathways to establish national
numerical pollutant limits for practices
that beneficially land apply sewage
sludge. The Agency considered allowing
a treatment works the flexibility to
conduct site-specific exposure
assessments and recalculate pollutant
limits for each land application site
using the 14 exposure pathways
evaluated in the final rule, but decided
not to allow the site-specific option for
land application practices for several
reasons.
First, site-specific pollutant limits
would have to be developed on a site-
by-site basis for possibly thousands of
land application sites. Given the
complexity of the 14 exposure pathways
and the amount of data needed to field
validate and verify each exposure
assessment, the Agency determined that
it would not be economically practical
for a treatment works to conduct as
many as 14 exposure pathway
assessments for each land application
site. In addition, the Agency believes
that the administrative burden on
permitting authorities to review and
approve site-specific numerical limits
on a case-by-case basis for thousands of
land application sites would not be
feasible and is beyond the self-
implementing nature of today's final
rule.
Second, many of the parameters in the
14 exposure pathways are based on
Agency risk policy decisions (e.g., an
RfD for an inorganic pollutant). EPA
does not believe that values for these
parameters should be changed
regardless of site-specific conditions
and that any variation in these pathways
or parameters could result in numerical
pollutant limits that are not adequate to
protect public health and the
environment. Finally, if the Agency
restricts which pathways and
parameters can be used or varied in a
site-specific exposure assessment to
those that are not critical from an EPA
risk policy standpoint, the Agency does
not believe that the numerical limits
recalculated from such a "limited"
exposure assessment would result in
less stringent cumulative pollutant
loading rates. Therefore, conducting or
evaluating a site-specific exposure
assessment based on varying only a few
parameters in a few pathways would not
be a prudent use of limited resources
since it would not make a significant
difference in the numerical limits for
the site.
In support of site-specific soil testing
for land application practices, it is
possible that inorganic pollutant
concentrations measured in the soil may
be less than the allowable pollutant
concentrations from the exposure
pathway assessment after the
cumulative inorganic pollutant loading
limits are reached because of losses due
to leaching and plant uptake. However,
EPA believes that these losses would be
small and would not significantly
increase site-life beyond pathway
predicted values. Further, any small
anticipated increase in site-life would
-------
9310 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
not justify the administrative burden of
conducting and evaluating site-specific
soil tests and exposure assessments. For
the above reasons, the final part 503
regulations do not allow site-specific
soil testing for land on which sewage
sludge is applied.
The Agency also considered for the
final rule whether to allow site-specific
pollutant limits for surface disposal
practices including sludge-only
landfills. Because the part 503 surface
disposal limits are based only on the
results of the vapor and ground water
pathways, EPA determined that site-
specific pollutant limits are feasible for
all surface disposal practices. However,
the Agency does not believe it is
feasible, on a site-specific basis or
otherwise, to modify Pathway 13
(surface disposal vapor pathway) or
Pathway 14 (surface disposal ground
water pathway) to account for the
amount of a pollutant that may be taken
up by animals or vegetation on the site
from the quantity of pollutant available
for vaporizing to air or leaching to
ground water. The Agency believes that
such losses would be insignificant, if
quantified, having little effect on site-
specific numerical pollutant limits for
those pathways.
As discussed earlier, the Agency also
evaluated the potential risks to wildlife
from surface disposal practices and
found that wildlife exposure was not
significant enough to develop numerical
limits using the wildlife exposure
pathways for these practices. Because of
the physical nature of these sites, active
surface disposal sites do not provide a
suitable habitat for many plant or
animal species. This is supported by
current evidence that does not indicate
significant levels of foraging or other
biological activities that would lead to
significant exposure for these practices.
For these reasons, the final part 503
regulation allows site-specific pollutants
limits for surface disposal practices but
does not allow the exposure pathways
to be modified to reduce the amount of
pollutants vaporizing to air or leaching
to ground water after accounting for
pollutant uptake by plants and animals
on the site.
Final Action
In today's rule, the option of
recalculating numerical pollutant limits
based on certain site-specific conditions
would bo available for treatment works
that dispose of their sewage sludge in
surface disposal sites (including
monofills) on a case-by-case basis.
The final rule balances the flexibility
associated with site-specific analyses
against the simplicity of national
numerical limits. A rule that allows
exceptions for every conceivable
contingency would prove difficult to
understand. Moreover, implementation
of such a rule would require an
unwarranted commitment of the
Agency's limited resources. Therefore,
exceptions to national pollutant limits
are based on certain site-specific
conditions that would make a
significant difference in the pollutant
limits but not their protectiveness.
Although the Agency's preference is
for treatment works to use sewage
sludge for its beneficial properties,
EPA's responsibility is to set standards,
for each practice, that are adequate to
protect public health and the
environment. Section 405 (e) of the CWA
requires treatment works generating or
treating sewage sludge, as well as
persons using or disposing of sewage
sludge, to comply with the technical
standards. Realistically, the Agency
cannot issue permits to every user of
sewage sludge. Therefore, the site-
specific option is not allowed for land
application practices and primary
responsibility is placed on treatment
works for ensuring that sewage sludge
meets the requirements of the rule.
The approach that the Agency is
promulgating in the final rule utilizes a
combination of national numerical
limits and case-by-case site-specific
exposure modeling for surface disposal
practices. Under certain conditions the
treatment works would calculate new
numerical limits based on the physical
and environmental conditions at the
surface disposal site. The treatment
works will not have to collect data on
all model parameters at the site. To
ensure that site-specific limits are
protective of public health and the
environment, the Agency will not allow
the treatment works to vary long-
established Agency human health or
environmental criteria such as RfDs,
RfCs, MCLs, etc., or other parameters
that would reduce the level of
protectiveness in the site-specific limit.
The conditions, exposure pathway
models and site-specific parameters
(e.g., depth to ground wate:-, soil type
and permeability, etc.) for which a
treatment works may submit site-
specific data and exposure pathway
assessments will be provided in
supplemental guidance issued by EPA
shortly after promulgation of the final
part 503 rule.
Application of Sewage Sludge to Frozen
or Snow-Covered Land
Comments on the Proposed Approach
Many commenters objected to EPA
restricting the application of sewage
sludge to frozen or snow-covered land.
The commenters maintained that
sewage sludge could be applied to
frozen or snow-covered land in an
environmentally sound manner if
certain precautions were taken at the
site, such as considering slope,
separation distance, soil type,
conservation practice, and hydraulic
loading.
Response to Comments
The Agency agrees that good
management practices, such as
vegetative cover and run-off
containment can control pollutant
migration from frozen or snow-covered
lands where sewage sludge is applied.
In the part 503 proposal, the Agency
proposed to prohibit the application of
sewage sludge to frozen, snow-covered,
or flooded land unless the applier could
demonstrate that the sewage sludge
could be applied in a manner that will
not cause a discharge of pollutants into
waters or wetlands in violation of any
requirements set forth by the Clean
Water Act. The Agency believes that
sewage sludge applied to frozen, snow-
covered, or flooded lands could readily
be transported off the site with the first
melt or rainfall into a river, stream, lake,
or wetland. These uncontrolled releases
could result in adverse impacts to
sensitive environmental areas such as
spawning habitats located in wetlands.
In addition, 26 States already impose
similar restrictions on the land
application of sewage sludge to prevent
such environmental abuse.
Final Action
The final part 503 rule prohibits the
application of sewage sludge to frozen
or snow-covered land if the sewage
sludge will cause a discharge of
pollutants into waters or wetlands in
violation of Clean Water Act
requirements. This requirement does
not apply to sewage sludge or sewage
sludge products that are sold or given
away for use in home gardens. In
addition, bulk sewage sludge and bulk
products containing sewage sludge may
not be applied to flooded land. Shortly
after promulgation, the Agency will
issue separate guidance explaining how
appliers can demonstrate compliance
with this and other Clean Water Act
requirements.
Set-Back Requirements
Comments on the Proposed Approach
Several commenters requested the
Agency to include in the final part 503
regulations additional set-back
requirements for distances from sewage
sludge land application sites to ground
water, bedrock, residences, property
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9311
lines, drinking wells and surface water
bodies. One commenter stated that these
set-back requirements should depend on
site-specific conditions, such as soil
type, pH, and slope, while limiting
applications during adverse conditions.
Other commenters suggested set-back
distances between land application sites
and private and public wells of 200 and
1000 feet, respectively. One commenter
felt that the 10 meter set-back used in
the proposed rule was not sufficient to
protect surface waters from pollutants in
sewage sludge. Another commenter
suggested prohibiting sewage sludge
application sites where the depth to
ground water is less than one meter.
Response to Comments
The Agency disagrees that the part
503 rule should include additional or
more stringent set-back requirements, or
prohibit the land application of sewage
sludge if the depth to ground water is
less than one meter. The numerical
limits established by the exposure
assessment models are based on
"reasonable worst-case" parameters
such as one meter depth to ground
water and 10-meter set-back from
surface water. Under these conservative
conditions the Agency believes the
numerical limitations are adequate to
protect public health and the
environment from reasonably
anticipated adverse effects of pollutants
found in sewage sludge that is land
applied. In addition, the Agency has
required other management practices
and siting restrictions to further protect
public health and to prevent
environmental abuse.
Anyone using or disposing of sewage
sludge is obligated to comply with the
requirements set forth in the part 503
rule. Moreover, in the case of surface
water, section 405{a) of the CWA
already prohibits, except in accordance
with an NPDES permit, any disposal of
sewage sludge if the disposal would
result in any pollutant from the sludge
entering navigable waters. However, as
provided in section 405(d)(5) and
section 510 of the Clean Water Act,
States may impose more stringent
requirements than those included in the
part 503 regulations. In fact, many
States and local governments already
have zoning and set-back requirements
that address many of the concerns
raised by the commenters.
Final Action
The Agency has decided to retain the
proposed set-back requirements in the
final part 503 regulations for all land
application practices, and not to expand
or increase their stringency. However,
the Agency has removed the proposed
set-back requirements for sewage sludge
and sewage sludge products that are
sold or given away (referred to as
distribution and marketing in the
proposal) in the final part 503 rule
because data provided during the public
comment period showed that
distributed and marketed sludge
products do not pose a significant
surface water pollution problem from
run-off. The Agency believes the
numerical limitations derived from the
exposure pathway analyses for land
application practices, in addition to the
set-back, siting and management
practice requirements contained in the
final rule are adequate to protect public
health and the environment. In
addition, States are free to impose more
stringent requirements if needed, and in
many cases already have set-back and
zoning laws that address the issues
identified in the public comments.
Nitrogen Limitations for Non-
Agricultural Land Application
Comments on the Proposed Approach
Many commenters argued that the
proposed requirement for the
application of sewage sludge to non-
agricultural land, which states that the
amount of nitrogen applied may not
exceed the nutrient needs of the
vegetation grown on the site, would
prevent the beneficial use of sewage
sludge for many of the non-agricultural
land practice categories such as forest
land, soil reclamation, and other
beneficial use practices. The
commenters maintained that, since non-
agricultural land application
encompasses a number of very different
practice categories each having a
different nitrogen management
philosophy, the Agency should revise
its agronomic rates requirement.
Response to Comments
The Agency agrees that the agronomic
rates requirement may not be consistent
with certain beneficial non-agricultural
land practices such as land reclamation.
As noted, the proposal included a
provision that sewage sludge could not
be applied at rates in excess of the
nitrogen requirements of the vegetation
(e.g., trees, grasses, etc.) and at rates that
would cause the excess nitrogen in the
sewage sludge to leach to the ground
water. The objective of such a
requirement is to satisfy the removal of
the nitrogen requirements for optimal
plant growth and to minimize nitrate
contamination of ground water.
Sewage sludge contains three to five
percent nitrogen. Nitrogen may be in the
form of organic nitrogen, nitrogen as
ammonia, and nitrogen as nitrate.
Organic nitrogen is the predominant
form of nitrogen in sewage sludge and
decomposes into ammonia and nitrate.
Ammonia is the form of nitrogen
absorbed by the plant. Ammonia not
absorbed by the plant may volatilize or
has the potential to oxidize and form
nitrate, a water soluble anion that moves
readily downward into the soil profile.
High levels of nitrate in drinking water
supplies may result in health problems
for both infants and livestock. The
drinking water standard is 10
milligrams of nitrogen as nitrate per liter
of water.
The nitrogen requirements of different
plants can range from 50 to over 350
kilograms per hectare (45-312 pounds
per acre). The nitrogen content of the
sewage sludge, cropping patterns, plant-
available nitrogen in the soil,
supplemental fertilizers used, climatic
conditions, and method of sewage
sludge application also affect the
amount of nitrogen that plants can
effectively absorb from the sewage
sludge.
Final Action
The Agency has decided to revise the
agronomic rates requirement in the final
regulations for land application
practices. The final part 503 rule allows
the application of bulk sewage sludge at
rates designed to minimize the amount
of nitrogen that passes below the root
zone of the crop or vegetation grown on
the site to ground water. For land
reclamation, the permitting authority
may authorize (by permit) a variance
from this requirement provided the
owner or operator of the site can
demonstrate that nitrogen application in
excess of crop and vegetative
requirements would not contaminate
ground or surface water. The Agency
recognizes that allowing such a variance
may cause a temporary pulse of nitrogen
to occur in ground water or surface
water near the site. However, the
Agency believes that any minor
excursion granted by the permitting
authority would not be of sufficient
duration or magnitude to produce
adverse public health or environmental
effects. Any slight potential for negative
impacts from a temporary nitrogen
pulse would be more than offset by the
beneficial effects of land reclamation
such as decreased acid run-off, erosion
control, attenuation of inorganic and
organic pollutants, and increased soil
nutrient levels.
Rather than establish a national
numerical limit for nitrogen for all land
application practices, the Agency is
requiring that the agronomically
appropriate sewage sludge application
rate be established by the permitting
-------
9312 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
authority based on site-specific land
management practices. Guidance is
available to assist in establishing the
appropriate application rate from the
"Process Design Manual—Land
Application of Municipal Sludge"
(Reference number 61) and from County
Extension Service agents, State
Extension soil fertility specialists, and
State and local Soil Conservation
Service agents.
Part 503 Vs. Part 258
Comments on the Proposed Approach
Several commenters recommended
that, in the part 503, EPA regulate
monofills (now regulated with surface
disposal practices) in the same way as
40 CFRpart 258 regulates MSWLFs in
areas such as location criteria, closure
requirements, long-term care,
monitoring, and financial responsibility.
They felt that the proposed part 503
regulations failed to recognize the
importance of these areas and of: (1)
Proper liner design or other engineering
measures necessary to prevent pollutant
migration; (2) engineering controls that
allow for efficient collection and
management of leachate; (3) ground
water monitoring to assure that the
monofill maintains its integrity; (4) a
mechanism for triggering "corrective
action" when the integrity of a monofill
is compromised; (5) and a financial
assurance mechanism to assure that the
monofill can be closed properly at the
end of its useful life. Some commenters
were especially concerned that the
proposed part 503 rule only regulated
16 pollutants in sewage sludge while
the part 258 regulations addresses
monitoring requirements for over 200
constituents. Other commenters
maintained that allowing sewage sludge
to be co-disposed with municipal solid
waste without developing the numerical
limitations for the co-disposed sludge
did not comply with section 405 of the
Clean Water Act.
Response to Comments
The Agency disagrees that, in the part
503 regulations, EPA must regulate
surface disposal practices (that now
includes sludge-only landfills—
monofills) in the same way it has
regulated municipal solid waste
landfills and include the pollution
containment requirements adopted in
the part 258 rule in addition to the
numerical pollutant concentration
limits. The 40 CFR part 258 rule is a
pollutant containment rule that
specifies minimum Federal criteria for
municipal solid waste landfills
(including landfills that accept sewage
sludge along with municipal solid
waste). Among these requirements are
location restrictions, facility design and
operating criteria, ground water
monitoring, and corrective action,
closure and post-closure care, along
with financial assurance requirements.
The part 258 rule regulates municipal
solid waste landfills using all these
technical considerations.
In contrast to the part 258 rule, the
part 503 rule seeks to limit the addition
to the environment of pollutants from
sewage sludge rather than contain the
pollution on site. Thus, part 503
requires a quality of sewage sludge such
that there will be no unacceptable
impacts from the migration of
pollutants. Therefore, conservative risk
and exposure models were utilized to
establish numerical limitations with an
adequate margin of safety for pollutants
in sewage sludge so that the resulting
pollutant concentrations reaching a
highly exposed individual through
ground water are below human health
criteria (maximum contaminant levels).
Ground water monitoring and corrective
action would be redundant and are,
therefore, not needed for this controlled
release approach. This approach
depends on accurately characterizing
the quality of sewage sludge through
monitoring and controlling the sewage
sludge quality through programs such as
categorical pretreatment standards and
local pretreatment programs. States
may, of course, impose additional
requirements if they desire.
By contrast, provisions of the part 258
regulationscfor municipal solid waste
landfills control sewage sludge that is
placed in these facilities through a
facility design and management practice
approach. The part 503 regulations
adopted today for surface disposal sites
include numerical pollutant limits that
are adequate to protect public health
and the environment from any adverse
effects from pollutants found in sewage
sludge and to control-the quality of
sewage sludge through these limits for
each use and disposal practice. By
setting risk-based pollutant limits to
control sewage sludge quality, the
Agency ensures that public health and
the environment are adequately
protected for those use and disposal
methods regulated in part 503.
For purposes of section 405 of the
CWA, in part 503, EPA has adopted the
part 258 criteria as the appropriate
standard under section 405 for sewage
sludge disposed of with municipal
waste. EPA concluded that if sewage
sludge is disposed of in a MSWLF
complying with part 258 criteria, public
health and the environment are
protected. Although section 405 of the
Clean Water Act indicates a preference
for numerical pollutant concentration
limits to protect public health and the
environment, the statute recognizes that
development of scientifically defensible
pollutant limits may not always be
possible for all sewage sludge use and
disposal practices. Thus, section
405(d)(3) provides:
Alternative Standards—For purposes of
this subsection if, in the judgment of the
Administrator, it is not feasible to prescribe
or enforce a numerical limitation for a
pollutant identified under paragraph (2), the
Administrator may instead promulgate a
design, equipment, management practice, or
operational standard, or combination thereof,
which in the Administrator's judgment is
adequate to protect public health and the
environment from any reasonably anticipated
adverse effects of such pollutants (CWA
405(d)(3)).
In developing the part 258 criteria, the
Agency evaluated the technical
feasibility of establishing numerical
limits for sewage sludge that is co-
disposed with solid waste in municipal
solid waste landfills. In that rulemaking,
EPA determined that it is not
technically feasible to establish
numerical criteria for sewage sludge
being disposed at these facilities since
any potential environmental or human
health affects clearly be dominated by
the solid waste component in the
disposal facility. Therefore, EPA
adopted, for purposes of co-disposed
sludge regulation, the part 258 design
and management criteria. Sewage sludge
co-disposed with solid waste at landfills
meeting the requirements of part 258
will satisfy the statutory directive of the
Clean Water Act because the part 258
regulations have been determined to be
as protective of public health and the
environment as the part 503 regulations.
Even though the approaches used in
parts 258 and 503 are different, both
approaches accomplish their statutory
directive to protect public health and
the environment.
Final Action
Standards for sewage sludge that is
disposed of in a landfill with municipal
solid waste are established in 40 CFR
part 258. Compliance by treatment
works with requirements of 40 CFR part
258 constitutes compliance with section
405. The part 258 standards are jointly
promulgated under the authorities of
sections 4004 and 4010 of RCRA and
section 405(d) of the CWA. To meet
these standards, treatment works must
ensure that: (1) The sewage sludge sent
to MSWLFs is not hazardous, as defined
by the regulatory limits in 40 CFR part
261; and (2) the sewage sludge passes
the Paint Filter Liquids Test (i.e., it
contains no free liquids).
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9313
In the preamble to the MSWLF rule,
EPA explained its judgment that it is not
technically feasible to establish
numerical limitations for the pollutants
which may be present in sewage sludge
that is co-disposed in municipal
landfills. 56 FR 50978, 50996-50997
(October 9,1991). In lieu of such
numerical limitations, EPA promulgated
an extensive set of rules pertaining to
the design, management practices, and
engineering standards for MSWLFs
which co-dispose sewage sludge. (56 FR
50978-51119, October 9,1991). As
required under CWA section 405(d)(3),
EPA determined that these alternative
standards were adequate to protect
public health and the environment. Id.,
at 50997.
EPA has provided a sound technical
and scientific basis for its CWA section
405 (d) (3) determination that numerical
limitations could not be set for sludge
co-disposed in municipal landfills. In
the proposed part 258 rule, EPA made
a tentative determination under CWA
section 405 (d) (3) that it was not feasible
to prescribe numerical limitations for
pollutants in co-disposed sludge. EPA
based this determination on the
conclusion that sludge constitutes only
a minor portion of all waste that is
disposed of in municipal landfills (e.g.,
5 percent by volume) and that is not
scientifically possible to separate out
the fate, transport, and environmental
effects of pollutants in sludge from
those contaminants contained in the
vast amount of other waste disposed of
in the landfill. 53 FR 33314, 33320,
33322 (August 20, 1988).
In the final part 258 rule (56 FR
50978, 50996-50997), EPA explained
that there were no scientifically
adequate mathematical models which
could be used to assess the movement
of sewage sludge pollutants from
disposal facilities which also accept
other types of waste, such as municipal
landfills. Id., at 50997. EPA determined
that, in contrast to disposal situations
where sewage sludge is disposed of in
a sludge-only facility, there were too
many scientific uncertainties
concerning the chemical interactions
between sludge pollutants and those
pollutants contained in garbage and
other household waste when all were
mixed in a municipal landfill. Id.
Given these uncertainties, EPA
concluded that no existing model,
including the model which had been
utilized to propose numerical
limitations for sludge pollutants when
the sludge is used or disposed of on its
own (54 FR 5764-5778 (February 6,
1989)), could track the fate of sludge
pollutants in a municipal landfill. As a
consequence, the Agency determined
that it could not prescribe with any
degree of scientific certainty the
appropriate numerical limitations for
such sludge pollutants in co-disposed
situation. Id.
Moreover, EPA concluded that there
was a significant absence of data on the
typical levels of pollutants contained in
household waste which is co-disposed
with sludge in municipal landfills. Id.
Without some knowledge about the
character of the household waste
component in a co-disposal facility and
its effect on the potential of toxic
pollutants to leach from the landfill, the
Agency determined that it was
"impossible to calculate limitations for
the sludge pollutants." Id.
The information EPA considered for
part 258 fully supports EPA's
determination under CWA section
405(d)(3) that the operational, design,
and engineering standards which are
incorporated into the MSWLF rule are
adequate to protect public health and
the environment from any reasonably
anticipated adverse effects of toxic
pollutants in sewage sludge co-disposed
in municipal landfills. 56 FR 50978,
50997 (October 9,1991).
Ground Water Monitoring and
Degradation
Comments on the Proposed Approach
Several commenters maintained that a
mechanism to ensure ground water
protection was not provided in the part
503 proposal because ground water
monitoring provisions were not required
for monofills. The commenters stated
that the only way to guarantee
compliance, and to ensure that design
and construction controls work is to
require ground water monitoring.
Another commenter advocated requiring
ground water monitoring for all sewage
sludge monofills, land application sites,
and surface disposal sites unless
conditions warranting an exemption
could be demonstrated.
Other commenters suggested that the
Agency develop a national "non-
degradation policy" for all ground
waters underlying monofills rather than
establishing national numerical
limitations, and that national
regulations should not allow the
deliberate pollution of ground waters.
However, another commenter argued
that EPA does not have the statutory
authority under the Clean Water Act to
establish a national ground water non-
degradation policy as part of the part
503 rulemaking.
Response to Comments
The Agency disagrees that it must
require ground water monitoring to
ensure ground water protection.
Further, the EPA disagrees that a
national "non-degradation policy" is
needed to protect all ground waters
underlying monofills or that it lacks the
statutory authority under the Clean
Water Act to establish such a policy if
in the future the Agency determines that
such a policy is necessary to protect
public health and the environment.
A fundamental regulatory principle
used in developing the part 503 rule is
prevention of environmental harm. The
Agency believes that it is more
protective and cost effective to prevent
sewage sludge contamination by
controlling pollutants at the source than
it is to require clean-up of the
contaminated ground water. Therefore,
controlling the quality of sewage sludge
placed in the monofill is an overriding
objective of the part 503 standards.
This up-front sewage sludge pollution
prevention approach is different from
the alternative approach taken in the
"Solid Waste Disposal Facility Criteria"
40 CFR part 258 (see 56 FR 50978,
October 9,1991). The criteria for
MSWLFs use location, design, and
operating criteria to achieve a ground
water protection performance standard.
In addition to those criteria, the Agency
also requires that owners or operators of
MSWLFs monitor the ground water and
take corrective action when necessary.
This ground water monitoring serves as
a method of verifying the adequacy of
the design and operation of a particular
MSWLF. Ground water monitoring and
corrective action were mandated for the
regulations by section 4010 of RCRA "as
necessary to detect contamination."
Consistent with its pollution
prevention objective, the part 503 rule
requires that treatment works monitor
the quality of sewage sludge before the
sewage sludge is used or disposed of at
any site. EPA's analysis based on the
available scientific and technical
information, indicates that if the
pollutant concentrations do not exceed
the limits in the part 503 regulations,
the pollutants are unlikely to migrate to
the ground water, especially at levels
that exceed the drinking water
standards. In such circumstances, the
Agency believes that requiring ground
water monitoring and corrective action,
in addition to sewage sludge testing, is
not justified or necessary to protect
public health and the environment.
Final Action
The Agency has decided to retain the
proposed pollution prevention approach
and numerical pollutant limitations for
sewage sludge quality to ensure
protection of ground waters underlying
sewage sludge use and disposal sites.
-------
9314 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Tho Agency has not established a
national non-degradation policy for all
ground waters but will consider such a
policy in future rulemakings if the
Agency determines it is necessary to
further protect public health and the
environment from the use or disposal of
sewage sludge.
The Agency used exposure
assessment models to simulate the
movement of the pollutant into and
through the soil profile to the ground
water. The models calculate a pollutant
concentration that will not exceed an
MCL at the point of compliance. For
land application practices, the point of
compliance is the point where the
loachate enters the aquifer. For surface
disposal practices, the point of
compliance is immediately below the
property boundary or 150 meters from
the sewage sludge unit boundary,
whichever is less.
The Agency's objective in establishing
the pollutant limits for the use and
disposal of sewage sludge is to ensure
that the pollutant concentrations
reaching the ground water do not
exceed the drinking water standard or,
if no drinking water standard exists,
other appropriate human health criteria.
This ground water protection standard
is the basis for the Agency's
determination that the pollutant limits
are adequate to protect public health
and the environment from any
reasonably anticipated adverse effect of
a pollutant.
Surface Disposal Vs. Treatment/Storage
Comments on the Proposed Approach
Numerous commenters argued that
the one year cut-off for designation as a
sewage sludge surface disposal site (as
opposed to a treatment or storage site)
is unrealistic and should be changed.
Many commenters felt that interim
storage and treatment should be
excluded from the definition of surface
disposal, and that the definition did not
clearly differentiate between long and
short-term storage or between treatment
and disposal. Several of the commenters
suggested cut-off limits for storage and
treatment ranging from two to 10 years.
Other commenters maintained that
surface disposal sites should be
regulated the same as monofills, or that
exceptions should be made for facilities
with adequate ground water protection
such as liners.
Response to Comments
Tho Agency agrees that the one year
time period may not adequately
differentiate surface disposal from
treatment or storage. As modified in the
final rule, the Agency believes that the
definition accurately captures the
critical elements distinguishing
treatment from storage. For treatment
works, the final rule provides an
opportunity to demonstrate that storage
may require retention for a greater
period than the regulatory baseline. EPA
concluded that, applying these
standards, regulatory authorities and
permit writers can distinguish among
facilities used for sewage sludge
treatment, storage and disposal.
In the proposal, the Agency defined a
surface disposal site as an area of land
on which only sewage sludge is placed
for a period of one year or longer. The
one year time period was used to
differentiate surface disposal from
treatment or storage practices not
covered under the part 503 rule.
In 1984, when the Agency initiated
the part 503 rulemaking process, surface
disposal sites were considered surface
impoundments that were used for
treatment or interim storage, not
permanent disposal facilities.
Subsequently, the Agency has learned
that some communities use surface
impoundments for extended periods of
time, suggesting that the practice is, in
fact, the community's method of
disposal. When surface impoundments
are used for the final disposal of sewage
sludge, they are surface disposal sites
and are subject to the CWA's
requirements as a disposal method. The
CWA requires the Agency to develop
standards for use or disposal methods
that are adequate to protect public
health and the environment from any
adverse effect of each pollutant.
Sewage sludge is applied to the land
for use or disposal. Sewage sludge is
applied to agricultural and non-
agricultural land, and sewage sludge
products are distributed in commerce
for use in home gardens, to take
advantage of the nutrient and soil
conditioning properties of sewage
sludge. However, surface disposal
practices do not use the nutrient and
soil conditioning properties for a
beneficial use. Rather, many of these
disposal practices use the soil simply to
bind the metals and use soil
microorganisms, sunlight, and oxidation
to destroy the organic matter in the
sludge. Disposing of sewage sludge in
monofills is also a method of surface
disposal that does not use the beneficial
characteristics of sewage sludge.
Final Action
Based on public comment and
information obtained from the National
Sewage Sludge Survey, the Agency has
decided to increase the one year time
period used to differentiate sewage
sludge surface disposal from treatment
or storage to two years. The Agency
believes a two year time period is
appropriate for differentiating sewage
sludge surface disposal from treatment
and storage, and has made this change
to the definition of surface disposal
because certain treatment practices (e.g.,
composting, sludge drying beds, etc.)
and storage facilities may process and
store sewage sludge for periods
exceeding the proposed one year time
limit. The Agency believes that permit
writers will be better able to distinguish
between those facilities legitimately
treating and storing sewage sludge and
those practicing surface disposal if EPA
specifies a general time limitation. For
the purpose of the final rule, the Agency
has also merged application of sludge to
dedicated land and disposal in
monofills (i.e., sludge-only landfills)
under the definition of surface disposal.
The two year time limit will reduce
the burden on the regulated community
operating legitimate treatment and
storage facilities. The yardstick permit
writers must apply to distinguish
between legitimate use and disposal
practices is the two year time limitation.
If retained and not treated for more than
two years, the sewage sludge is
presumed to be disposed. If the practice
does not meet this simple test it is
subject to the part 503 surface disposal
regulations. If stored or treated the
sludge is not subject to these
regulations. For flexibility in cases
where the facility legitimately treats or
stores for periods longer than two years,
the owner or operator of the facility can
prepare an explanation (for review by
the permitting authority, if requested) as
to why treatment or storage must
continue beyond the two year limit and
gain relief from this requirement.
Feasibility of THC Monitoring
Comments on the Proposed Approach
Many commenters indicated that total
hydrocarbon (THC) monitoring has not
been shown to be practical for sewage
sludge incinerators and carbon
monoxide (CO) monitoring should be
used instead. These commenters
suggested CO monitoring since it has
been demonstrated in other incinerator
applications and is simpler to operate
and maintain. Some commenters argued
that THC monitoring is more costly than
EPA estimated and would result in
many sewage sludge incinerators having
to install afterburners unnecessarily.
Other commenters recommended that
EPA should use THC monitoring to
determine overall combustion efficiency
of the incinerator and set minimum
temperatures, or specify afterburners to
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9315
ensure complete destruction or organic
pollutants.
Response to Comments
The Agency disagrees that THC
monitoring is not feasible for sewage
sludge incinerators or that afterburners
need to be required to ensure complete
destruction of organic pollutants.
Because of questions raised about the
feasibility and reliability of the THC
monitoring of sewage sludge incinerator
emissions, EPA sponsored a long-term
demonstration of a heated flame
ionization detection (FID) system for use
as a THC monitor at the Metropolitan
Waste Control Commission (MWCC),
Metropolitan Wastewater Treatment
Plant in St. Paul, Minnesota. The plant
has six multiple hearth sludge furnaces,
with wet venturi scrubbing systems and
waste heat recovery boilers. A heated
total hydrocarbon measuring
instrument, a Beckman Model 402, was
installed on incinerator No. 9 on June
19,1989.
The MWCC plant was selected for this
study because the plant's management
approached the Agency about
conducting a cooperative research
activity and the incinerator facility has
a sophisticated computer control system
that allows for the collection and
analysis of incinerator and air pollution
control device operating data.
The objectives of the study were as
follows:
1. Demonstrate the feasibility and
long term reliability of an FID system on
a full scale sewage sludge incinerator.
2. Determine the costs of operation
and maintenance of the FID monitor.
3. Evaluate the effects of various
incinerator operating parameters on
THC emissions such as operating
temperatures, excess air rates, transient
operating conditions, and scrubber
operation.
4. Correlate the organic emissions
from the incinerator with the THC
readings to strengthen the Agency
incinerator emission data base and to
further support the regulation of total
organic compound emissions through
the regulation of THC emissions.
The heated FID system operated
satisfactorily over the two year study.
Several modifications to the standard
gas sampling system were made that
contributed to the success of the project.
a. A ISO-degree shroud was installed
on the upstream side of the sintered
metal stack sampling probe. This has
the effect of reducing the direct impact
of stack gas stream particles on the
sintered metal sampling probe and is
believed to greatly reduce plugging of
the sampling probe.
b. The sintered metal sample probe is
routinely back purged with calibration
gases during the bi-weekly instrument
calibration and maintenance check.
c. The temperature of the sampling
system instrument was raised from 150
°C to 190 °C. At 190 °C, erratic behavior
of the system ceased and stable
operation was achieved. It is theorized
that at the 150 °C operating temperature,
moisture in the stack gas was causing
the unstable operation. It appears that at
least for the St. Paul incinerator system,
which has a stack temperature of 90-
100 °F (32-38 °C), 190 °C is necessary
for successful operation. Based on this
experience, each facility will be able to
arrive at its own optimum operating
temperature of at least 150 °C.
With these modifications of the FID
system, the system performed quite
well. During the study, the THC system
was operational approximately 95
percent of the time. Most of the
instrument down time was due to the
normal maintenance shut-down of the
incinerator itself.
The hot FID instrument collected data
which were used in a number of
analyses. For example, the THC levels
in the stack have been found to correlate
very well (correlation co-efficient,
1^=0,90) with the top hearth gas
temperatures. Carbon monoxide
instrument data do not show as good a
correlation with either top hearth gas
temperatures or THC data. A second
heated FID system was put into
operation on October 10, 1989. The
readouts of both instruments correlate
very well, with only a 10 percent
difference between the two THC
readouts. Additional parametric tests on
upset operating conditions and scum
burning were conducted. Also
measurements of emissions of
individual semi-volatile and volatile
organic compounds were conducted so
that EPA could better correlate THC
measurements with total organic
compound emissions and better
understand the health risks associated
with THC readings.
The operating and maintenance costs
of the hot FID system at St. Paul have
been documented. For the period of
June 19,1989 to December 31,1989,160
labor hours were spent on operation and
maintenance of the system. The Agency
feels that this is a reasonable effort to
ensure that emissions of organic
pollutants are controlled to acceptable
health risk levels.
EPA conducted additional
demonstrations of THC and CO
monitoring on sewage sludge
incinerators in fiscal years 1991 and
1992. Results of these demonstrations
further showed the viability of
continuous THC/CO monitoring of
sludge combustion systems (Reference
number 110). EPA is now convinced
that THC monitoring is a viable
regulatory tool.
Final Action
Based on study data, the Agency has
decided to require THC monitoring
using a heated flame ionization
detection system to control organic
emissions from sewage sludge
incinerators. The results of the study
demonstrate the feasibility and long
term reliability of THC monitoring using
a heated (150 °C) FID system. Operating
and maintenance costs are competitive
with other monitoring systems used in
sewage sludge incinerators such as
carbon monoxide monitors. In addition,
THC reading from the FID system
showed excellent correlation with
organic pollutant emissions for the
sewage sludge incinerators tested.
Incinerator Stack Height Option
Comments on the Proposed Approach
Nine commenters supported a part
503 provision that would allow owners
and operators of sewage sludge
incinerators the flexibility of raising
their stack heights using "good
engineering practice" (GEP) to meet
numerical pollutant limits before
requiring the installation of best
available control technology (BACT) air
pollution control equipment. Many of
the commenters felt that this would be
an appropriate provision for the risk-
based part 503 rule because many
existing facilities have relatively short
stacks that can result in downwash
exposing incinerator operators and
nearby citizens to high levels of
incinerator emissions. Two commenters
opposed the raising of incinerator stacks
arguing that deposition exposure and
the overall aggregate risk from
incinerator emissions would not be
reduced by increasing stack height.
Besponse to Comments
The Agency agrees that owners and
operators of sewage sludge incinerators
should have the option of raising the
height of their stacks using GEP (as
required under 40 CFR 51.100) to meet
part 503 numerical pollutant limitations
before taking other corrective measures
such as installing expensive air
pollution equipment. In the proposal,
the Agency solicited comments on
whether to deny owners and operators
of incinerators an opportunity to raise
the height of their stacks after the
effective date of the rule, as the means
of complying with the numerical limits
in the rule. Raising the stack height
-------
9316 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
increases the amount of dispersion,
thereby reducing the concentration of
the pollutants that reach the MEL
However, increasing the height of stacks
does not reduce the mass emissions of
tho pollutants. Therefore, national
cancer incidence (the number of cancer
cases due to the pollutants being
emitted) may not change significantly, if
owners or operators choose to meet
those requirements by merely increasing
tho height of their stacks.
The legislative history of section 405
of the CWA directs the Agency to
establish numerical limits that protect
the health of individuals or populations
which are at higher risk than the
population as a whole (Cong. Rec.,
S1624, October 16,1986). If, in
complying with pollutant limitations,
all incinerators in the regulated universe
install pollution control equipment
(such as afterburners and wet
electrostatic precipitators), EPA's
analysis showed that in addition to
protecting the HEI, reductions would
occur in the total number of projected
cancer cases as well as the number of
projected adverse lead health effects.
The Agency has concluded that
allowing credit for actual stack height
up to GEP stack height would protect
the HEI and would not increase the
projected number of cancer cases
(incidence) nationwide.
Final Action
The Agency has decided to allow
owners and operators of sewage sludge
incinerators the flexibility of increasing
the height of their stacks up to GEP
height (see 40 CFR 51.100) in
determining allowable numerical
pollutant limits in the final part 503
rule. The Agency believes that this
approach will continue to protect highly
exposed individuals and will not
increase the aggregate risk to the
population as a whole from incinerator
emissions at facilities that chose the
stack height option as a means of
complying with part 503 numerical
pollutant limitations.
Incinerator Lead Emissions Limitation
Comments on the Proposed Approach
Commenters were divided on how the
Agency should establish the lead
omissions limitation for sewage sludge
incinerators. Three commenters
advocated setting the allowable lead
emissions limit based on the ambient air
lead levels at each facility. Another
commenter argued that since lead
omissions from other sources were being
reduced by the Agency under other
regulations, a lead emissions standard
for sewage sludge incinerators was
premature. One commenter questioned
the Agency's logic for the 25 percent of
the National Ambient Air Quality
Standard (NAAQS) assumption used to
derive the lead emissions limit. Still
other commenters were supportive of
the proposed lead emissions limit and
agreed with the Agency's 25 percent
portion of the National Ambient Air
Quality Standard for lead as the basis
for the incinerator lead emissions
standard.
Response to Comments
A number of commenters supported
the Agency's approach for establishing
the lead emissions limitation for sewage
sludge incinerators. However, the
Agency concluded that some
modifications to the proposed approach
were necessary to take into account site-
specific ambient lead levels in order to
protect highly exposed individuals and
populations from incinerator lead
emissions. The Agency disagrees that a
lead emissions standard for sewage
sludge incinerators is premature
because of lead reductions imposed by
other EPA regulations, or that the
Agency's logic used in establishing the
lead emissions limitation is flawed.
In the proposal, EPA designed the
standard to limit lead emissions from
sewage sludge incinerators so that the
ground level concentration of lead
would not exceed 25 percent of the
NAAQS for lead. The current NAAQS
for lead is 1.5 micrograms per cubic
meter (ug/m3) maximum arithmetic
mean averaged over a calendar quarter
(see 40 CFR 50.12).
In deriving an allowable ground level
concentration for lead from the
incineration of sewage sludge, the
Agency evaluated the following two
alternatives: 10 percent of the NAAQS,
the percent used in the revisions to the
Hazardous Waste Incinerator regulation,
and 25 percent of the NAAQS. States
allocate a percentage of the NAAQS to
various sources of lead emissions in
non-attainment areas through State
Implementation Plans (SIPs). At the
time of proposal, most States had not
included limits for sewage sludge
incinerators in their SIPs, leading the
Agency to believe that States did not
consider sewage sludge incinerators a
significant source of lead emissions.
However, allocation of a large
quantity of the air-shed loading to
sewage sludge incinerators is
inconsistent with the Agency's goal to
minimize lead exposure from all sources
because of the significant biological
changes that occur across a broad range
of exposures to lead (down to very low
levels). Limiting the contribution of lead
from sewage sludge incinerators to 10
percent of the NAAQS level (i.e., 0.15
ug/m3) would be consistent with this
goal. However, allowing sewage sludge
incinerators alone to contribute
potentially up to 25 percent of the
NAAQS may be excessive since
allowing that increment could allow
ambient lead levels in some areas to rise
substantially from the present average
background level of 0.1 ug/m3. In
addition, EPA's aggregate risk
assessment showed lead emissions from
sewage sludge incinerators to be the
primary source of potential adverse
health effects from lead when compared
to other sludge use and disposal
practices. The Agency's proposed
approach to use 25 percent of the
NAAQS was EPA's initial step in
regulating lead from sewage sludge
incinerators and to ensure that the
increase in ground level ambient
concentration of lead would not exceed
the current lead NAAQS.
Final Action
The Agency has decided to revise its
standard for limiting lead emissions
from sewage sludge incinerators to 10
percent of the NAAQS for lead because
the Agency's aggregate risk assessment
shows lead emissions from sludge
incinerators are the primary source of
Eotential adverse health effects from
sad, especially in small children,
compared to other sewage sludge use
and disposal practices.
In the final rule, the ground level
concentration of lead contributed from
the sewage sludge incinerator [exposure
concentration to the highly exposed
individual (HEI)] may not exceed 10
percent of the NAAQS for lead. The
minimum ground level concentration of
lead being contributed by a sewage
sludge incinerator that must be achieved
regardless of the ambient air lead
concentration is 10 percent of the
NAAQS for lead. However, States may
wish to further limit the emission of
lead from sewage sludge incinerators if
it is warranted in non-attainment areas.
The 1978 NAAQS for lead was
designed to ensure that 99.5 percent of
the population has blood lead levels
below 30 micrograms per deciliter (ug/
dl), the level then judged to provide an
adequate margin of safety from adverse
health effects. The Agency now has data
indicating that much lower blood lead
levels are associated with a variety of
adverse health effects in men, women,
and particularly, in the very young. EPA
is currently reviewing the current
NAAQS for lead and will incorporate
this new information. Until a new
NAAQS is promulgated for lead, the
current NAAQS will be the basis of the
numerical limit when sewage sludge is
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9317
incinerated. When EPA revises the
current NAAQS of 1.5 ug/m3, the owner
or operator of the sewage sludge
incinerator is required under the part
503 regulations to revise the numerical
limit for lead for the sewage sludge
incinerator. The EPA believes that the
revised standard used in the final part
503 rule is consistent with new
information about low-level adverse
health effects and the Agency's goal to
minimize lead exposure from all
sources.
Alternative Pollutant Limits
Comments on the Proposed Approach
Many commenters on both the
proposal and the 1990 NSSS notice
urged EPA to develop standards for a
"clean sludge" (i.e., a sewage sludge
that receives minimal regulation if the
sewage sludge meets certain quality
requirements).
Response to Comments
The Agency concurs in the view that
protection of public health and the
environment does not require the same
level of regulatory control for "clean
sludge." The requirements that a sewage
sludge has to meet under this concept
are discussed below and the reduction
in regulatory requirements for that
sewage sludge are discussed in the
section on Final Action.
Results of the exposure pathway
assessment for land application of
sewage sludge provide cumulative
pollutant loading rates for inorganic
pollutants. These rates are the
maximum amount of a pollutant that
can be applied to a unit area of land
consistent with protection of public
health and the environment from
reasonably anticipated adverse effects of
pollutants in sewage sludge.
EPA also considered an alternative to
a cumulative pollutant loading rate:
determination of a pollutant
concentration that, if not exceeded in
the sewage sludge, would provide
adequate protection. EPA derived the
pollutant concentration from
calculations using the already
established cumulative pollutant
loadings. Then, by applying certain
conservative assumptions, EPA back-
calculated to a pollutant concentration.
Because the pollutant concentration is
based on the cumulative pollutant
loading rate and includes conservative
safety factors, it provides the same
degree of protection to human health
and the environment as provided by the
cumulative pollutant loading rate.
Calculation of the pollutant
concentration and the other parts of the
"clean sludge concept" are discussed
below.
To convert a cumulative pollutant
loading rate to a pollutant
concentration, two things must be done.
First, the cumulative pollutant loading
rate must be converted to an annual
pollutant loading rate. For today's final
rule, this was done by assuming that the
entire cumulative load for a pollutant is
applied to a hectare of land in one year.
Thus, to convert the cumulative
pollutant loading rates to annual
pollutant loading rates, the cumulative
pollutant loading rates were divided by
one year. EPA believes this is a
conservative assumption because it is
unlikely that the cumulative load for the
inorganic pollutants controlled in
today's final rule will be applied to a
hectare of land in one year.
Second, the annual pollutant loading
rates calculated above were converted to
pollutant concentrations using the
following equation:
APLR
AWSAR x 0.001
(1)
Where:
C = pollutant concentration in mg/kg (dry
weight basis).
APLR = annual pollutant loading rate in
kg/hectare/365 day period (dry weight
basis).
AWSAR = annual whole sludge
application rate in metric tons/hectare/
365 day period (dry weight basis).
0.001 = a conversion factor.
The annual pollutant loading rate
used in equation (1) is the cumulative
pollutant loading rate divided by 100
years. The other variable in the equation
is the annual whole sludge application
rate (AWSAR).
The Agency assumed the AWSAR
used in equation (1) is 10 metric tons
per hectare per year for 100 consecutive
years. EPA believes that the pollutant
concentrations derived from this
equation are conservative because it is
unlikely that any one site will receive
10 metric tons of sewage sludge per
hectare per year for 100 consecutive
years. In addition, the nutrient
requirements of crops grown on
agricultural land most likely will not
require that sewage sludge be applied to
the land every year for 100 consecutive
years. A typical AWSAR for agricultural
land based on crop nutrient
requirements is 7 metric tons per
hectare. Typical AWSARs for a public
contact site, forest, and a reclamation
site are 18, 26, and 74 metric tons per
hectare, respectively. Thus, for
agricultural land, a public contact site,
forest, or a reclamation site, the Agency
has determined based on the following
analysis that pollutant concentrations
derived from equation (1) provide an
adequate level of public health and
environmental protection because
sewage sludge could be applied for
significantly more consecutive years
than would actually occur at such sites
given their nutrient requirements.
If sewage sludge is applied to
agricultural land at an AWSAR of 7
metric tons per hectare; to a public
contact site at an AWSAR of 18 metric
tons per hectare; to forest at an AWSAR
of 26 metric tons per hectare; and to a
reclamation site at an AWSAR of 74
metric tons per hectare and if the
sewage sludge meets the pollutant
concentrations calculated using
equation (1), approximately 142 years,
55 years, 38 years, and 13 years,
respectively, are required before the
cumulative loading rate for a pollutant
is exceeded. The Agency has concluded
that it is unlikely that sewage sludge
will be applied to those types of land for
greater than the above number of years
for each type of land.
As discussed above, the Agency
believes the pollutant concentrations
calculated using equation (1) only
should be part of the "clean sludge
concept." The other parts of that
concept are pathogen requirements and
vector attraction requirements. To
minimize the regulatory requirements
for a sewage sludge that meets certain
requirements, EPA believes that a
sewage sludge should meet the highest
quality requirements in today's final
rule for pathogens. Those are the Class
A requirements. If Class A pathogen
requirements are met, no restrictions are
imposed on the site where the sewage
sludge is applied.
The Agency also believes that certain
vector attraction requirements should be
met to minimize the regulatory
requirements for a sewage sludge. This
is achieved if the sewage sludge meets
one of eight vector attraction
requirements in the final regulations. If
a sewage sludge meets the pollutant
concentrations calculated using
equation (1), the more stringent Class A
pathogen requirements in today's
regulations, and one of eight vector
attraction requirements in the final rule,
EPA believes that the regulatory
requirements for that sewage sludge can
be reduced if the sewage sludge is
applied to the land. This reduction is
discussed below.
Final Action
Today's final rule indicates that if a
sewage sludge or material derived from
sewage sludge meets the pollutant
concentrations for high quality sludge in
Table 3 of section 503.13, the more
-------
9318
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
stringent Gloss A pathogen
requirements, and one of eight vector
attraction requirements; the general
requirements and management practices
in tho final regulations for land
application do not apply if the sewage
sludge or material derived from sewage
sludge is applied to the land. The
minimum frequency of monitoring,
rocordkooplng, and reporting
requirements in the land application
subpart do apply, however, if the
sowage sludge or material derived from
sewage sludge is applied to the land.
Those requirements apply because the
Agoncy has to have information to
determine whether the sewage sludge or
material derived from sewage sludge
moots the above three quality
requirements.
The reduction in the applicability of
tho land application general
requirements and management practices
applies both to bulk sewage sludge
applied to the land and to sewage
sludge sold or given away in a bag or
similar enclosure for application to the
land. As mentioned above, it also
applies to a material derived from a
sewage sludge. The material in this case
is derived from a sewage sludge that
does not meet the three quality
requirements discussed above.
The final regulations address another
situation for the "clean sludge concept."
That situation concerns a material
derived from a sewage sludge that meets
tho pollutant concentrations in Table 3
of soction 503.13, the Class A pathogen
requirements, and one of the eight
vector attraction requirements. Because
tho sewage sludge meets those three
requirements, neither the land
application standards (i.e., general
requirements and management
practices) the minimum frequency of
monitoring requirements, the
racordkeoping requirements, nor the
reporting requirements in the land
application subpart apply if the material
derived from the sewage sludge is
applied to the land. This is true for both
a material applied to the land and to a
material sold or given away in a bag or
similar enclosure for application to the
land.
Part IX: Selection of Pollutants for
Regulation
The final sludge use and disposal
regulations establish numerical
pollutant limits for 10 metals and an
operational standard for total
hydrocarbons emitted from sewage
sludge incinerators. The proposed
regulation would have established
numerical pollutant limits for 28
inorganic and organic pollutants, as
well as total hydrocarbons. After further
analysis of information provided on the
proposal and the data from the NSSS,
the Agency decided not to establish
numerical pollutant limits in the final
part 503 rule for certain pollutants
which the Agency had proposed to
regulate for the reasons explained
below.
Section 405 does not direct EPA to
establish use and disposal standards for
all pollutants. Rather, the statute
requires EPA to develop numerical
pollutant standards for pollutants
"which, on the basis of available
information on their toxicity,
persistence, concentration, mobility, or
potential for exposure, may be present
in sewage sludge in concentrations
which may adversely affect public
health or the environment." 33 U.S.C.
1345. EPA applied these criteria when
it identified pollutants that it evaluated
and proposed for regulation. However,
in the final rule, the Agency determined
that certain pollutants should not be
regulated because they either are not
present in sludge, or if present in the
sewage sludge, the potential for
exposure (and consequent health or
environmental risk) is small.
EPA concluded a pollutant is not
present in concentrations which pose a
public health or environmental risk
using the following criteria:
(1) The pollutant is banned or
restricted by the Agency or no longer
manufactured or used in manufacturing
a product. Or,
(2) The pollutant is not present in
sewage sludge at significant frequencies
of detection based on data gathered from
the NSSS. Or,
(3) The Agency's risk assessment for
the pollutant shows no reasonably
anticipated adverse effects on public
health or the environment at the 99th-
percentile concentration found in
sewage sludge from the NSSS.
Initially the Agency selected
pollutants for regulation in the part 503
proposal based on a comparison of the
highest observed concentration of the
pollutant found in the "40 City Study"
with a safe pollutant concentration
derived from its screening assessment
(i.e., an exposure assessment based on a
very simple and over protective
exposure model). If the highest observed
concentration of the pollutant from the
"40 City Study" was less than the
pollutant concentration from the
screening assessment, the pollutant was
not proposed for regulation in "Round
One."
As discussed in part V, the Agency
determined prior to proposal that
POTWs selected for analysis in the "40
City Study" were not representative of
all the POTWs in the United States
because the study was not statistically
designed for that purpose. Moreover, the
Agency concluded that pollutant
concentrations from the study did not
accurately represent sludge quality and
that some sludges may be more
contaminated than those observed. As a
result of these and other deficiencies,
the Agency conducted the National
Sewage Sludge Survey. The NSSS was
specifically designed to resolve the
deficiencies in the "40 City Study" data
base and to allow EPA to accurately
estimate percentile concentrations of
pollutants in sludge throughout the
United States. However, the NSSS was
not perfect in every respect.
In developing the above criteria, the
Agency selected pollutant
concentrations based on the 99th-
percentile from the NSSS because of
uncertainty in higher percentile
concentrations. Because sludge quality
had improved since the "40 City
Study", the Agency found when it
conducted the NSSS that many
pollutants were at such low
concentrations that they were not
detectable, even using advanced
analytical methods. Because of the large
number of nondetectable readings for
organics, extrapolation to higher
concentration values for those
pollutants would create a high degree of
uncertainty in the pollutant
concentrations. For example, N-
nitrosodimethylamine was not detected
in any of the samples analyzed for the
NSSS. However, the calculated highest
value based on use of detection limit
estimates is 1,090 mg/kg. The Agency .
determined that the 99th-percentile
pollutant concentration estimates
significantly reduced this uncertainty
and used this percentile in its criteria to
select pollutants for regulation in the
final rule.
The Agency determined that it would
not establish numerical pollutant limits
for any pollutant meeting one of the
three criteria. For example, if a pollutant
is banned from production, it is highly
unlikely that it will be present in
sewage sludge, and there is no
consequent need to establish numerical
limits for that pollutant. In the case of
a number of banned and no longer
manufactured pesticides that EPA had
proposed to regulate, examination of the
NSSS data also confirmed that these
pesticides were not present in sewage
sludge.
One advantage of the approach the
Agency has adopted for the final rule is
that it will save monitoring resources so
that POTWs can focus on looking for
only those pollutants of concern.
Fourteen pollutants met the criteria
detailed above and are no longer
-------
Federal Register / Vol. 58, No. 32 /Friday, February 19, 1993 / Rules and Regulations 9319
regulated in the final part 503 rule:
Aldrin/dieldrin, benzene,
benzo(a)pyrene, bis(2-ethylhexyl)
phthalate, chlordane, DDT (and its
derivatives ODD and DDE), dimethyl
nitrosamine, heptachlor,
hexachlorobenzene,
hexachlorobutadiene, lindane,
polychlorinated biphenyls, toxaphene,
and trichloroethylene. Further details
on the analysis used in deciding not to
regulate these pollutants is provided in
Appendix A (Justification for the
Deletion of Pollutants from the Final
Standards for the Use or Disposal of
Sewage Sludge) of the Technical
Support Document for Land
Application.
Table IX-1 lists the 11 pollutants for
which the Agency is promulgating
numerical limits when a particular use
or disposal practice is employed.
TABLE IX-1 .—POLLUTANTS FOR WHICH
NUMERICAL LIMITS ARE PROMULGATED
IN PART 503
Pollutants
Arsenic
Cadmium
Chromium
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Total hydrocarbons 1
Zinc
LA
X
x
x
x
x
x
x
x
x
x
10
SD
x
x
x
3
I
x
x
x
x
x
x
6
. 'Total hydrocarbon emissions encompass all
organic compounds in the emissions of an
incinerator.
Key:
LA—land application.
SD—surface disposal (including monofill).
I—incineration.
Part X: Aggregate Risk Assessment for
the Final Part 503 Regulation
This part of the preamble discusses
the aggregate risk assessment conducted
to evaluate the effects of the final part
503 regulation on public health. EPA
performed this evaluation by first
estimating the "baseline" public health
impacts of sewage sludge use and
disposal without the part 503
regulation. Next, EPA assessed the
public health impacts after
implementing the final part 503
regulation. The difference between these
two estimates is the public health
"benefit" of the final part 503
regulation.
The aggregate risk assessment was
designed to estimate both the expected
national human health risks associated
with current baseline use and disposal
of sludge and the benefits of the
regulation measured in terms of
estimated reductions in human health
risks. Methods for determining these
risks differ for each of the management
practices (incineration, surface disposal
and land application). In general, the
Agency used a sample of plants from the
analytical component of the National
Sewage Sludge Survey to represent the
larger universe of actual facilities and
used additional information on these
plants from the questionnaire portion of
the NSSS. EPA then developed a profile
of national sewage sludge use and
disposal practices based on the
information obtained in the NSSS.
Further, EPA also used NSSS data to
assign pollutant concentrations under
baseline conditions to plants in different
categories.
Data describing cancer potency or
other types of dose-response effects
were then used to translate estimated
exposure to each pollutant into
measures of individual risk. Results
were then aggregated to determine the
likely number of individuals
experiencing each relevant health effect
expected per year in the affected
populations as a result of exposure to
sludge pollutants. For those pollutants
for which dose-response relationships
could not be obtained, predicted
exposure was compared to risk
reference doses, describing thresholds of
exposure below which adverse health
effects are not expected. Estimated
health risks from these plants under
current practices were extrapolated
using weighting factors from the survey
and other data describing the current
inventory of sludge incinerators to
calculate risks at the national level.
More details on the aggregate risk
assessment may be obtained from the
document entitled "Human Health Risk
Assessment for the Use and Disposal of
Sewage Sludge: Benefits of Regulation."
Information on obtaining single copies
of this document is provided in part
XIV.
Surface Disposal
For those plants reporting the use of
surface disposal for managing their
sludge, data describing the volume and
quality of the sludge disposed were
obtained from the NSSS. Other sources
provided data describing location,
topography, design and operation of
surface disposal sites. These two types
of data were used by the Agency to
examine the possible migration of
pollutants from these sites to nearby
ground water or ambient air in order to
determine baseline health effects. Data
for the density of human populations
and drinking water wells in each county
containing a sampled surface disposal
facility were used to determine the size
of the population likely to be exposed
to various levels of pollutants near the
surface disposal sites. Next, the Agency
estimated die likely dose of each
pollutant to subgroups of exposed
populations. These estimates of
exposure were combined with available
dose-response data and the estimated
sizes of exposed populations to predict
likely individual and aggregate health
risks resulting from the disposal of
sludge. Finally, results were
extrapolated to the national level using
weighting factors developed from the
surveyed facilities to estimate aggregate
risks from surface disposal practices
under current conditions.
Results of the baseline assessment
indicate less than 0.1 cancer case, less
than 1 individual who exceeded a
threshold blood lead level associated
with adverse lead effects, and less than
1 individual experiencing lead-induced
hypertension or learning disabilities
associated with the placement of sewage
sludge on a surface disposal site. Post-
part 503 effects remain less than 0.1
cancer case, less than 1 individual who
exceeds a threshold blood lead level,
and less than 1 individual with a lead
case from the placement of sewage
sludge on a surface disposal site. This
indicates a low impact on public health
from placement of sewage sludge on a
surface disposal site before
promulgation of the rule and even a
greater level of protection after
implementation of the final part 503
regulation.
Land Application
For predicting the impacts from land
applying sewage sludge, the Agency
used average values for the
concentrations of each pollutant
measured in the sludge of facilities
practicing land application from the
NSSS. Again, the Agency used
mathematical models to predict the
transport of pollutants to nearby ground
water and ambient air for the baseline
assessment. However, additional models
were used to predict the uptake of
pollutants from treated soil to
agricultural crops and animal tissues
and to estimate contamination of surface
water. Based on average population
densities and assumptions about the
distribution of treated produce in
national markets, the Agency estimated
current human exposure to and risk
from each pollutant in sludge and
through each relevant pathway of
exposure from prototype facilities. As
with surface disposal, the final step in
the assessment of current risks was to
extrapolate results to the national level,
based on the estimated number of
facilities practicing land application and
the quantity of sludge applied.
-------
9320 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
As explained earlier, the basic
strategy for calculating health benefits is
to estimate health risks under current
conditions, estimate health risk after
regulation, and subtract to estimate
health benefits achieved by the
regulation. The above analysis was done
to determine the aggregate effects before
implementation of the final part 503
regulation (i.e., at baseline) and after
implementation of the final part 503
regulation. The baseline assessment
resulted in less than 1 cancer case,
approximately 1000 individuals for
whom a threshold lead concentration is
exceeded, and approximately 500
individuals experiencing lead-related
effects (i.e., hypertension in adult males
and children with reduced Intelligence
Quotient) associated with the
application of sewage sludge to the
land. In no case did the average
exposure to the other inorganic
pollutants for which limits are included
in the land application exceed the
reference dose for the pollutant during
the baseline assessment.
Results of the aggregate risk
assessment after implementation of the
final part 503 land application
regulations are less than 1 cancer case,
less than one individual who exceeds a
blood lead level, and less than one lead
case. This establishes that the rule
adopted today will protect public health
and ensure that continued disposal of
sludge will not jeopardize public health
in the future.
Sewage Sludge Incineration
For those plants reporting the use of
incineration for managing their sludge,
data describing the volume and quality
of the sludge incinerated were obtained
from the NSSS. Other sources provided
data describing local meteorology and
likely emissions of pollutants from these
facilities. These two types of data were
combined as inputs for mathematical
models to predict (on a site-specific
basis) the fate and transport of emitted
pollutants. Resulting estimates for
expected concentrations of pollutants in
ambient air were next combined with
site-specific data describing the
locations and sizes of human
populations residing near the facilities
sampled. By mapping predicted ground-
level concentrations of each pollutant
(by geographic location) onto the
locations and sizes of human
populations near each facility, the
Agency determined the expected dose of
each pollutant received by exposed
individuals under current conditions.
For estimating benefits from the
regulation of sewage sludge
incineration, the Agency estimated
expected response of individual
facilities that are expected to be out of
compliance with the regulation. The
Agency then assumed that those
facilities would choose to install and
operate pollution control equipment in
order to comply with the rule. Estimated
emissions for each individual
incinerator in the survey were adjusted
for the estimated efficacy of that
facility's expected control measures to
estimate emissions after compliance
with the part 503 regulation. After these
adjustments, all calculations were
repeated to determine expected
exposure and risk to surrounding
populations. As before, these results
were extrapolated to the national level
based on the estimated volume of sludge
incinerated annually and results from
dispersion modeling of the full
inventory of known incinerators.
Results of the assessment prior to
implementation of the final part 503
regulation indicated 0.3-4 cancer cases,
700 people with blood lead levels that
exceed threshold levels for identified
adverse health effects, and 100 people
with lead-related adverse health effects
because of the firing of sewage sludge in
sewage sludge incinerators.
Implementation of the final part 503
regulation would reduce these risks to
0.2-4 cancer cases, 90 people with
blood lead levels that exceed a
threshold blood lead level, and 30
people with other lead-related health
effects cases because of firing of sewage
sludge in a sewage sludge incinerator.
Conclusions
The aggregate risk assessment
estimates that current use and disposal
practices contribute 0.9-5 cancer cases
annually, with a lifetime cancer risk to
a highly exposed individual ranging
from 6x10 ~4 for land application and
surface disposal of sludge to 7xlO~3 for
incineration. The other health effects
associated with sewage sludge use and
disposal are primarily related to lead
exposure and result in approximately
2,000 individuals who exceed a
threshold blood lead level associated
with adverse health effects and 700
instances of hypertension or diminished
learning capacity in children. The
Agency estimates that the rule reduces
cancer cases by 0.09-0.7, exceedences of
lead adverse health threshold by 600-
2,000 and instances of lead cases by 90-
600.
These results indicate that current use
and disposal practices for sewage sludge
pose little risk to public health. Because
of uncertainties in estimated emissions
of organic pollutants from incinerators,
estimates of baseline risks are reported
as ranges, where the lower extreme of
each range is based on "best estimates"
of emissions, and the higher extreme is
based on "worst case" estimates. For
"best estimates" of emissions, the
Agency used mean reported values of
emissions for each organic pollutant
tested. For samples in which a
particular pollutant was not detected,
limits of detection were used in
calculating the mean. "Worst case"
estimates are based on these same
values and limits of detection, except
they represent a 99th-percentile
confidence limit for the mean. In
addition, "worst case" estimates of
cancer risks have been adjusted by a
factor of five to account for the
possibility that up to 80 percent of the
carcinogenic pollutants in organic
emissions may not have been identified
and quantified and could possibly pose
risks comparable to those included in
the study. Use of "worst case" estimates
for emissions yields risk estimates about
a factor of 10 higher than those based on
"best estimates."
Because of uncertainties about the
likely response of individual POTWs to
the regulation, expected health benefits
from the regulation cannot be quantified
precisely. For incinerators, reductions
in emissions of metals have been
estimated from the assumed removal
efficiencies of additional pollution
control devices expected to be installed
at selected incinerator facilities. For
organic pollutants, however, sufficient
data were not available to determine to
what extent, if any, the standard for
total hydrocarbons will reduce
emissions. In the absence of such data,
the estimated benefits are based on the
assumption that emissions of organic
pollutants are not reduced; if emissions
are indeed reduced, benefits may have
been underestimated. Similarly,
sufficient data were not available for
determining how the regulation will
reduce human exposure and risk from
land application and surface disposal.
Estimates of benefits from regulating
these practices therefore range from zero
to 100 percent of estimated baseline
risks. Even though the estimated
baseline risks from all three practices
are very low, the assessment shows that
the adoption of the final standards for
land application, surface disposal and
incineration will ensure that these
methods of sludge use and disposal will
not pose any significant threat to public
health in the future.
Part XI: Description of the Final Part
503 Regulation
Introduction
This part describes the standards EPA
is promulgating in the final part 503
regulation for the use or disposal of
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9321
sewage sludge. The standards consist of
general requirements, pollutant limits,
management practices, operational
standards, and requirements that
address frequency of monitoring,
recordkeeping, and reporting. Today's
regulation requires that the following
persons maintain certain records: Any
person who generates sewage sludge or
derives a material from sewage sludge,
any person who applies sewage sludge
to the land, any owner/operator of a
surface disposal site, and any person
who fires sewage sludge in a sewage
sludge incinerator. The final regulation
also establishes reporting requirements
for Class I sludge management facilities,
publicly owned treatment works
(POTWs) with a design How rate equal
to or greater than one million gallons
per day, and POTWs that serve 10,000
people or more.
In the part 503 regulation, EPA uses
the phrases "land application," "apply
sewage sludge," and "sewage sludge
applied to the land" in a more
restrictive sense than their traditional
meaning to delineate sharply between
different regulatory requirements. As
previously explained, sewage sludge is
not only disposed on land as a waste
material but, in many cases, also is used
to condition the soil or to provide
nutrients. Thus, while sewage sludge
disposed on the land is obviously
"applied" to the land, the part 503
regulation uses the phrase "land
application", apply sewage sludge, or
"sewage sludge applied to the land
only when referring to sewage sludge
used for its beneficial properties. When
sewage sludge is disposed by placing it
on the land, the part 503 regulation
refers to this disposal practice as
"surface disposal."
Additionally, requirements for sewage
sludge applied to the land differ
depending on whether the sewage
sludge is "bulk sewage sludge" or
"sewage sludge sold or given away in a
bag or other container." EPA employs
these terms of art to distinguish the
situations in which bagged sewage
sludge is typically applied in small
amounts in a single application (e.g.,
home gardens)—called in today's rule
"sewage sludge sold or given away in a
bag or other container"—from those in
which sewage sludge may be applied in
large quantities over wide areas (e.g.,
agricultural use and reclamation
programs)—called "bulk sewage sludge"
for this regulation. In the proposed rule,
EPA described this small quantity
sewage sludge use as "distribution and
marketing" of sewage sludge (54 FR
5745 at 5880).
Further, many of the requirements in
the regulation apply to the "person who
prepares sewage sludge." The regulation
uses this term to describe the person or
entity that effectively controls the
quality of the sewage sludge or material
derived from sewage sludge that is
ultimately either used or disposed. In
cases where a treatment works' sewage
sludge is used or disposed without
further treatment or mixing with other
materials, the treatment works that
generates the sewaqe sludge is the
"person who prepares the sewage
sludge." In cases, for example, where a
treatment works generates sewage
sludge that is blended with other
substances, the person blending the
sewage sludge is the "person who
prepares the sewage sludge" because the
blender controls the quality of the
material that is ultimately used or
disposed.
The structure of the final part 503
regulation follows closely the structure
of the proposed part 503 regulation. The
final regulation includes standards for:
(1) Sewage sludge applied to the land
(including sewage sludge sold or given
away in a bag or other container for
application to the land—described in
the proposed rule as "distribution and
marketing"), (2) sewage sludge placed
on a surface disposal site (including
sewage sludge placed in a monofill),
and (3) sewage sludge fired in a sewage
sludge incinerator. The final part 503
regulation also contains a subpart on
pathogens and vector attraction
reduction.
The subpart on distribution and
marketing—now described as sewage
sludge sold or given away in a bag or
other container—in the proposed part
503 regulation now is incorporated into
the subpart on land application for the
final part 503 regulation. In addition,
the subpart on monofills and the
subpart on surface disposal are
combined in today's part 503 regulation.
Further, the subpart on removal credits
was moved from the part 503 regulation
to the pretreatment regulations in 40
CFR part 403.
EPA incorporated the proposed
subpart on distribution and marketing
into the land application subpart in the
final part 503 regulation to avoid
confusion. Sewage sludge that is sold or
given away in a bag or other container
(including sewage sludge sold or given
away in small quantities such as pick-
up truck loads) is obviously still
"applied to the land." Further, the part
503 regulation no longer employs the
phrase "distribution and marketing".
EPA concluded that the phrase "sold or
given away in a bag or other container
for application to the land" is a more
accurate description of the final use of
the sewage sludge. Distribution and
marketing implies that the sale or give
away of sewage sludge is its final use
rather than application to the land.
EPA combined the subparts on
monofills and surface disposal in the
proposal in the surface disposal subpart
in the final part 503 regulation because
the differences in characteristics
between surface disposal sites and
monofills did not merit separate
treatment. In either case, sewage sludge
is placed on the land for final disposal.
Both disposal practices may present
essentially similar potential threats to
public health and the environment.
EPA moved the subpart on removal
credits from the final part 503 regulation
because it logically belongs with the
pretreatment requirements. Lists of
pollutants eligible for a iomoval credit
with respect to the use or disposal of
sewage sludge are in the amendment to
the General Pretreatment Regulations
(40 CFR part 403) in today's rulemaking.
The final part 503 regulation contains
frequency of monitoring requirements
that are spelled out for each use or
disposal practice rather than in a
separate subpart as in the proposal.
Each subpart similarly includes
recordkeeping requirements and
reporting requirements for Class I sludge
management facilities, POTWs with a
design flow rate equal to or less than
one million gallons per day, and POTWs
that serve 10,000 people or more.
The final part 503 regulation also
contains two appendices. Appendix A
explains how to determine the annual
whole sludge application rate for
sewage sludge applied to the land. This
new appendix is included in the
regulation because the final part 503
regulation establishes limits based on
annual pollutant loading rates for
sewage sludge sold or given away in a
bag or other container that does not
meet the pollutant concentrations for
high quality sewage sludge in Table 3 of
section 503.13 of the regulation. The
annual pollutant loading rates are used
in the procedure described in appendix
A to determine the annual whole sludge
application rate for the sewage sludge.
Appendix B in today's part 503
regulation contains a description of
processes used to reduce pathogens in
sewage sludge. These processes are
similar to the pathogen reduction
processes described in appendix II of 40
CFR part 257. The vector attraction
reduction requirements in the process
descriptions in appendix II were deleted
from the process descriptions in
appendix B of today's regulation.
Separate requirements are included in
part 503 for vector attraction reduction.
Appendix D in the part 503 proposal
explained how to calculate the
-------
9322 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 /Rulesand Regulations
maximum combustion gas flow rate.
Tills appendix has been deleted from
the final part 503 regulation because of
a change in the requirements for
incineration of sewage sludge.
General Provisions (Subpart A)
Purpose and Applicability (Section
503.1)
The purpose of the final part 503
regulation is to establish standards that
must be met when sewage sludge is
used or disposed. The standards in the
part 503 regulation consist of general
requirements, pollutant limits,
management practices, operational
standards, and requirements for
frequency of monitoring, recordkeeping,
and reporting. The part 503 regulation
establishes standards for sewage sludge
applied to the land or disposed either by
placing on a surface disposal site or
firing in a sewage sludge incinerator.
The part 503 regulation also includes
requirements for reducing organisms in
the sewage sludge that cause disease
(pathogens). Either the Class A or Class
B pathogen requirements must be met
when sewage sludge is applied to the
land or placed on a surface disposal site.
Further, the regulation requires
reduction of vector attraction—control
of those characteristics of sewage sludge
that attract disease-spreading agents like
files or rats—when sewage sludge is
applied to the land or placed on a
surface disposal site. There are no
pathogen or vector attraction reduction
requirements for sewage sludge fired in
a sewage sludge incinerator because
pathogen and vector attraction
reduction is achieved during
incineration.
The Agency established limits for
pollutants in sewage sludge that could
adversely affect public health and the
environment and for which sufficient
information exists to evaluate risk
associated with those pollutants and to
develop numerical limits. For land
application, the pollutant limits along
with the management practices protect
public health and the environment from
the reasonably anticipated adverse
effects of arsenic, cadmium, chromium,
copper, lead, mercury, molybdenum,
nickel, selenium, and zinc in the sewage
sludge. EPA also evaluated the risks
associated with organic pollutants and
other inorganic pollutants applied to or
placed on the land in sewage sludge and
concluded that numerical pollutant
limits for those pollutants are not
required for the reasons explained in
part IX of today's preamble.
In the case of surface disposal, the
pollutant limits and management
practices in this subpart protect public
health and the environment from the
reasonably anticipated adverse effects of
arsenic, chromium, and nickel in the
sewage sludge. For incineration of
sewage sludge in a sewage sludge
incinerator, the pollutant limits and
management practices protect public
health from the reasonably anticipated
adverse effects of arsenic, beryllium,
cadmium, chromium, lead, mercury,
and nickel in the sewage sludge.
Also included in this part are
operational standards for pathogen
reduction and operational standards to
reduce vector attraction in sewage
sludge that is either land applied or
placed on a surface disposal site. In
addition, EPA is today establishing an
operational standard for sewage sludge
incinerators that limit the total
hydrocarbons (THC) in the exit gas from
a sewage sludge incinerator stack. The
absence of rigorous analytical tools and
pertinent data make the development of
numerical limitations infeasible for
pathogens, vector attraction reduction,
and organic pollutants in sewage sludge
that is incinerated.
Section 405((d)(3) authorizes the
Administrator to promulgate a design,
equipment, or operational standard
when in the judgment of the
Administrator it is not feasible to
prescribe or enforce a numerical
limitation for a pollutant. The
Administrator concluded that it is not
feasible, based on current information
and the state of analytical capability, to
develop numerical limitations for
pathogens, vector attraction reduction,
and THC at this time using the type of
exposure assessment employed to
develop numerical limitation for other
pollutants.
In the judgment of the Administrator,
the operational standards for pathogens
and for vector attraction reduction
protect public health and the
environment from the reasonably
anticipated adverse effect of pathogenic
organisms (e.g., certain bacteria, enteric
viruses, and helminth ova) in sewage
sludge and from the characteristics (e.g.,
odor) of the sewage sludge that attract
vectors (e.g., mosquitos and flies),
respectively. In the judgment of the
Administrator, the operational standard
for THC protects public health from the
reasonably anticipated adverse effects of
organic pollutants in the exit gas from
a sewage sludge incinerator stack.
The part 503 regulation also contains
frequency of monitoring requirements
for sewage sludge that is used or
disposed and recordkeeping
requirements for any person who
prepares sewage sludge or applies it to
the land, for the owner/operator of a
surface disposal site and for any person
who fires sewage sludge in a sewage
sludge incinerator. In addition,
reporting requirements for Class I sludge
management facilities, POTWs with a
design flow rate equal to or greater than
one million gallons per day, and POTWs
that serve 10,000 people or more are
included in the final part 503
regulation.
The recordkeeping requirements
indicate who must develop and retain
information, the information that must
be developed, and the period that the
information must be kept. These
requirements are included in part 503 to
make the rule self-implementing. This is
discussed further in other parts of this
preamble.
The final part 503 regulation requires
only Class I sludge management
facilities, POTWs with a design flow
rate equal to or greater than one million
gallons per day, and POTWs that serve
10,000 people or more to report
collected information. Other treatment
works must collect and retain
information for the specified period of
time. Those treatment works may have
to report the information to the
permitting authority on request.
Some or the requirements in part 503
apply to a person who prepares sewage
sludge (i.e., the person who either
generates sewage sludge during the
treatment of domestic sewage in a
treatment works or derives a material
from sewage sludge), applies sewage
sludge to the land, or fires sewage
sludge in a sewage sludge incinerator.
Other requirements apply to the owner/
operator of a surface disposal site. Still
others apply to (1) sewage sludge
applied to the land, placed on a surface
disposal site, or fired in a sewage sludge
incinerator, (2) the exit gas from a
sewage sludge incinerator stack, (3) land
on which sewage sludge is applied, (4)
a surface disposal site, or (5) a sewage
sludge incinerator.
Compliance Period (Section 503.2)
Section 405(d)(2)(D) of the Clean
Water Act, as amended, requires
compliance with the part 503 regulation
as expeditiously as practicable but in no
case later than 12 months after
publication of the final part 503
regulation, unless the final regulation
requires construction of new pollution
control facilities. If the final part 503
regulation requires construction of new
pollution control facilities, compliance
with the part 503 regulation is required
as expeditiously as practicable but in no
case later than two years from the date
of publication of the final part 503
regulation.
The Agency chose to apply the full 12
month and two year compliance periods
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9323
to the standards in the part 503
regulation, but not to the frequency of
monitoring, recordkeeping, or reporting
requirements, except for total
hydrocarbons. The only way to obtain
information about whether the
standards are met by the statutory
deadline is to start monitoring the
sewage sludge and keeping records
before the end of the 12 month
compliance period. For this reason, the
part 503 regulation indicates that the
frequency of monitoring, recordkeeping,
and reporting requirements, except for
total hydrocarbons in the exit gas from
a sewage sludge incinerator stack, are
effective 120 days after the effective date
of the regulation (i.e., 150 days after the
date of publication of the part 503
regulation).
The frequency of monitoring,
recordkeeping, and reporting
requirements for total hydrocarbons in
the exit gas from a sewage sludge
incinerator stack are effective 12 months
after the date of publication of this part,
unless compliance with the operational
standard for total hydrocarbons in the
part 503 regulation requires
construction of new pollution control
facilities. In that case, the frequency of
monitoring, recordkeeping, and
reporting requirements for total
hydrocarbons are effective two years
after the date of publication of the part
503 regulation.
The "date of publication" for the final
part 503 regulation is the date the
regulation is published in the Federal
Register. This date is different from the
"effective date" of the final regulation,
which is 30 days after the date of
publication of the final part 503
regulation in the Federal Register.
Permits and Direct Enforceability
(Section 503.3)
Section 405 (f) of the CWA provides
that each permit issued under section
402 of the CWA to a publicly owned
treatment works or to any treatment
works treating domestic sewage shall
include conditions to implement the
part 503 regulation, unless included in
permits issued under other enumerated
Federal or approved State programs. In
addition, the statute authorizes EPA to
issue permits to treatment works
treating domestic sewage solely to
impose conditions to implement the
regulation where none of the listed
permit programs apply. Thus, the part
503 requirements may be implemented
through a CWA permit, a subtitle C
Solid Waste Disposal Act permit, a part
C Safe Drinking Water Act permit, a
Marine Protection, Research, and
Sanctuaries Act permit, a Clean Air Act
permit, a permit under an approved
State program, or an EPA-issued "sludge
only" permit. However, the
requirements in part 503 must be met
even in the absence of a permit for the
use or disposal of sewage sludge (i.e.,
part 503 is self-implementing).
Consequently, the responsible person
must become aware of the standards in
part 503, comply with the standards,
monitor the sewage sludge, keep the
appropriate records, and, if applicable,
report information to the permitting
authority even when a permit is not
issued.
The standards in part 503 also are
enforceable directly against any person
who uses or disposes of sewage sludge
through one of the practices addressed
in today's final regulation. As
mentioned previously, the person who
uses or disposes of sewage sludge by
one of the part 503 practices must
become aware of the appropriate part
503 requirements and must comply with
those requirements. An enforcement
action can be taken against a person
who does not meet those requirements
even when that person does not have a
permit for the use or disposal of sewage
sludge.
Relationship to Other Requirements
(Section 503.4)
The conditions under which sewage
sludge may be disposed in a municipal
solid waste landfill unit are not
provided, for the most part, in part 503.
These standards are established in 40
CFR part 258. In that rule, the Agency
determined that public health and the
environment are protected from
reasonably anticipated adverse effects of
pollutants in sewage sludge when
sewage sludge is disposed in a
municipal solid waste landfill unit that
meets the criteria in part 258, as
discussed earlier. Disposal of sewage
sludge in a municipal solid waste
landfill unit (MSWLF) that meets the
part 258 criteria constitutes compliance
with section 405 (d) of the Clean Water
Act, as amended. EPA promulgated part
258 under both the authority of section
405 (d) of the CWA, as amended, and
sections 1008, 2002, 4004, and 4010 of
the Resource Conservation and
Recovery Act of 1978 (RCRA).
Part 503 also requires that the person
who prepares sewage sludge that is
disposed in a municipal solid waste
unit ensure that the sewage sludge
meets the part 258 requirements for
materials disposed in a municipal solid
waste landfill unit. The sewage sludge
must not be hazardous (§ 258.20) and
must pass the paint filter test (§ 258.28).
In addition, sewage sludge used to cover
a municipal solid waste landfill unit
must be suitable for that purpose
(§258.21). Implementation of the part
258 regulations with regard to siting and
operating the municipal solid waste
landfill unit must be done in accordance
with part 258 and subtitle D of RCRA
(56 FR 50978).
Another regulation that addresses
sewage sludge is EPA's storm water
regulation. Even though the final part
503 regulation does not have a storm
water requirement for sewage sludge
that is used or disposed, the Agency
concluded that it is important to
recognize the storm water regulation in
this preamble.
On November 16,1990, EPA
published a final rule implementing
section 402(p) of the CWA, which
required the Agency to establish a
regulation setting forth NPDES permit
application requirements for, among
other sources, storm water discharges
associated with industry activity. One of
the 11 categories of storm water
associated with industrial activity
required to be controlled under this
regulation is the following:
Treatment works treating domestic sewage
or any other sewage sludge or wastewater
treatment device or system, used in the
storage, treatment, recycling, and reclamation
of municipal or domestic sewage, including
land dedicated to the disposal of sewage
sludge, that are located within the confines
of the facility, with a design flow of 1.0 MGD
or more, or required to have an approved
pretreatment program under 40 CFR part 403.
Not included are farm lands, domestic
gardens or lands used for sludge management
where sludge is beneficially reused and
which are not physically located in the
confines of the facility, or areas that are in
compliance with section 405 of the CWA. (40
CFR 122.26(b)(14)(ix))
In establishing this category, EPA
viewed facilities such as large treatment
works that engage in activities that may
experience spills and bubbleovers (e.g.
on-site composting and storage of
chemicals) as suitable candidates for
storm water permits. Such treatment
works are considered to be engaged in
activities whose scope and size are more
akin to industry activity and, hence,
should be required to obtain an NPDES
permit for storm water discharges.
Treatment works that fit the above
description are required to pursue, by
the regulatory deadlines, one of the
application options provided under the
Agency's storm water regulation
(individual applications, group
application, or notice of intent to be
covered under a general permit) and to
comply with the terms and conditions
of any permit issued to cover discharge
of "storm water associated with
industrial activity".
-------
9324
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / RulesandRegidations
More Stringent Standards (Section
503.5)
This section of the part 503 regulation
provides the permitting authority the
authority to impose more stringent
standards for the use or disposal of
sewage sludge than the standards in the
part 503 regulation or to impose
additional requirements for the use or
disposal of sewage sludge. To impose
more stringent standards or additional
requirements, the permitting authority
(I.e., either EPA or a State with an EPA-
approved sludge management program)
must determine that the more stringent
standards or additional requirements are
needed to protect public health and the
environment from any adverse effect of
a pollutant in the sewage sludge.
One example of when a more
stringent standard may be imposed by
the permitting authority concerns land
applied bulk sewage sludge that meets
the pollutant concentrations in
503.10(b)(3), the Class A pathogen
requirements in 503.32(a), and one of
the vector attraction reduction
requirements in 503.33(b)(l) through
503.33{b)(8). Part 503 indicates that the
general requirements and management
practices in the land application subpart
do not apply when the bulk sewage
sludge meets these three requirements.
One of the management practices that,
in the general case, would apply to bulk
sewage sludge meeting the defined
requirements is the requirement to
apply the sewage sludge at an
agronomic rate. The permitting
authority may decide that, because of
conditions at a particular site, to protect
public health and the environment from
tho nitrogen in the bulk sewage sludge,
the bulk sewage sludge should be
applied to the land at an agronomic rate
oven though the bulk sewage sludge is
not subject to this requirement. Section
503.5(a) of part 503 allows the
permitting authority to impose the
agronomic rate requirement on the bulk
sowago sludge that is applied to the land
in defined circumstances.
As provided in section 510 of the
CVVA, as amended, States or political
subdivisions thereof or an interstate
agency also may impose more stringent
standards for the use or disposal of
sowago sludge than the standards in
today's final rule. A State or political
subdivisions thereof or an interstate
agency also may establish additional
requirements for the use or disposal of
sowago sludge as authorized by State
law.
Exclusions (Section 503.6)
This section of the final regulation
discusses exclusions from the part 503
regulation. These include treatment
processes, selection of a sewage sludge
use or disposal practice, co-firing of
sewage sludge, industrial wastewater
sludge, hazardous sewage sludge,
sewage sludge with a high PCB
concentration, incinerator ash, grit and
screenings, drinking water treatment
sludge, and commercial and industrial
Treatment of domestic sewage and
sewage sludge was addressed in the
applicability section in the part 503
proposal. That discussion was moved to
the section on exclusions in today's
final part 503 regulation to group all
exclusions in the same section.
The final part 503 regulation does not
establish requirements for the treatment
of domestic sewage. The standards
apply to the final use or disposal of
sewage sludge generated during the
treatment of domestic sewage in a
treatment works. For this reason,
processes used to treat domestic sewage
(e.g., the activated sludge process) are
not subject to the part 503 requirements.
The final regulation also does not
establish requirements for the treatment
of sewage sludge, except in the case of
those properties of sewage sludge, other
than its chemical composition, that may
pose a threat to public health and the
environment. Thus, requirements to
reduce pathogens and vector attraction
are provided in subpart D. Processes
used to prepare sewage sludge for final
use or disposal, such as composting, are
not subject to the standards in the final
part 503 regulation.
The pathogen requirements in the part
503 regulation are not based on the
results of an exposure assessment.
Instead, the requirements are
performance standards based on the
demonstrated ability of treatment
processes to reduce pathogens in the
sewage sludge. For this reason, some of
the pathogen requirements in the part
503 regulation address the treatment of
sewage sludge (e.g., raise the
temperature of the sewage sludge and
maintain the temperature for a specific
period of time).
Selection of a use or disposal practice
also was addressed in the applicability
section in the part 503 proposal. That
discussion was moved to the section on
exclusions in the part 503 regulation for
the reason mentioned above.
Although EPA encourages the
beneficial use of sewage sludge (e.g.,
through land application), the selection
of a sewage sludge use or disposal
practice, whether land application or
some other use or disposal practice, is
a local determination (e.g., the
responsibility of the municipality or
authority responsible for the use or
disposal of sewage sludge). For this
reason, the final part 503 regulation
does not establish requirements for the
selection of a sewage sludge use or
disposal practice. However, when the
selected use or disposal practice is
subject to the part 503 regulation, the
standards in the part 503 regulation for
that practice must be met when the
sewage sludge is used or disposed.
The final part 503 regulation also do
not establish requirements for co-firing
of sewage sludge with other wastes or to
the incinerator in which sewage sludge
and other wastes are co-fired. Other
wastes do not include auxiliary fuel
used in a sewage sludge incinerator.
Auxiliary fuel is fuel used to augment
the fuel value of sewage sludge. This
includes, but is not limited to, natural
gas, fuel oil, coal, and other fuels such
as gas generated during anaerobic
digestion of sewage sludge and
municipal solid waste. The municipal
solid waste must be equal to or less than
30 percent of the weight of the material,
including the sewage sludge, fired in the
sewage sludge incinerator on a dry
weight basis. When municipal solid
waste is greater than 30 percent of the
dry weight of the total material fired in
the incinerator, the part 503 regulation
does not apply to the material or to the
incinerator.
The final part 503 regulation does not
establish requirements for the use or
disposal of sludge generated at an
industrial facility during the treatment
of industrial wastewater because those
sludges are not sewage sludge. Sewage
sludge is generated during the treatment
of domestic sewage in a treatment
works. The appropriate requirements
(e.g., the requirements in 40 CFR part
257 when the sludge is disposed on the
land) must be met when industrial
sludges are used or disposed.
The Water Quality Act of 1987
expanded the applicability of section
405 (d) of the CWA to industrial
manufacturing and private processing
facilities that treat domestic sewage
combined with industrial wastewater.
Although the legislative history of the
1987 Water Quality Act indicates that
the Agency should impose requirements
on any treatment works that treats
domestic sewage, sufficient time was
not available to develop standards for
the use or disposal of sewage sludge
generated at industrial facilities during
the treatment of industrial wastewater
combined with domestic sewage. EPA
does not have sufficient information at
this time on the number of industrial
facilities that generate sewage sludge,
the amount of sewage sludge generated
at those facilities, and the practices
through which the sewage sludge is
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9325
used or disposed to evaluate the impact
of part 503 numerical limits for the
sewage sludge. In addition, the Agency
questions whether the models and data
used to develop the numerical limits in
the final part 503 regulation are
appropriate for industrial sludge with a
domestic sewage sludge component. For
these reasons, the part 503 regulation
does not establish requirements for the
use or disposal of sewage sludge
generated at an industrial facility during
the treatment of industrial wastewater
combined with domestic sewage (i.e.,
either domestic sewage generated at the
industrial facility or domestic sewage
generated off-site and transported to the
industrial facility for treatment). The
Agency may consider this sewage
sludge in future revisions to the part 503
regulation.
The part 503 regulation does apply to
sewage sludge generated at an industrial
facility during the treatment of only
domestic sewage. When domestic
sewage generated at an industrial
facility is treated at the industrial
facility without combining the domestic
sewage with industrial wastewater,
sewage sludge generated during the
treatment of the domestic sewage is
subject to the part 503 requirements.
Part 503 also applies to sewage sludge
generated when domestic sewage
generated off-site is treated only with
the domestic sewage generated at the
industrial facility or is treated at the
industrial facility by itself.
It is important to note that all
industrial wastewater treatment
facilities that treat domestic sewage—
whether the domestic sewage is
generated on-site or off-site—are
considered treatment works treating
domestic sewage and may be required to
apply for a permit under 40 CFR 122.21.
A detailed discussion of whether an
industrial wastewater treatment facility
needs a permit is presented in the
preamble to the sewage sludge
permitting regulations promulgated on
May 2,1989 (54 FR18716,18725).
The part 503 regulation also does not
establish requirements for sewage
sludge determined to be hazardous in
accordance with 40 CFR part 261. A
hazardous sewage sludge must be used
or disposed in accordance with the
applicable requirements in 40 CFR parts
260 through 268.
The part 503 regulation does not
establish requirements for the use or
disposal of sewage sludge that has a
concentration of polychlorinated
biphenyls equal to or greater than 50
milligrams per kilogram of total solids
(dry weight basis). Sewage sludge with
a polychlorinated biphenyls
concentration equal to or greater than 50
milligrams per kilograms of total solids
(dry weight basis) must be used or
disposed in accordance with the
requirements of 40 CFR part 761, not the
part 503 requirements.
Ash generated during the incineration
of sewage sludge in a sewage sludge
incinerator also is not subject to the part
503 regulation. Ash from a sewage
sludge incinerator must be used or
disposed in accordance with the
appropriate requirements (e.g., 40 CFR
part 257 when the ash is disposed on
the land).
Grit (e.g., small pebbles, sand, and
material with a high specific gravity)
and screenings (e.g., large materials
such as rags) generated during the
preliminary treatment of domestic
sewage in a treatment works that are
used or disposed are not subject to the
part 503 regulation. These materials
have characteristics that are different
than the characteristics of sewage
sludge. Grit and screenings also must be
used or disposed in accordance with the
appropriate requirements (e.g., 40 CFR
part 257 when the grit or screenings are
disposed on the land).
Sludge generated during the treatment
of either surface water or ground water
used for drinking also is not subject to
the part 503 regulation. That sludge is
not generated during the treatment of
domestic sewage in a treatment works.
The part 503 regulation does not
establish requirements for the use or
disposal of commercial and industrial
septage, a mixture of commercial and
domestic septage, or a mixture of
industrial and domestic septage.
Because the characteristics of domestic
septage and the characteristics of
commercial septage (e.g., grease from a
grease trap at a restaurant) and
industrial septage (e.g., liquid or solid
material removed from a septic tank or
similar treatment works that receives
industrial wastewater) are different, the
part 503 requirements for domestic
septage do not apply to commercial or
industrial septage. For this reason,
commercial and industrial septage are
excluded from the part 503 regulation.
Requirement for a Person Who Prepares
Sewage Sludge (Section 503.7)
Under the final part 503 regulation, a
person who prepares sewage sludge
must ensure that the applicable
requirements in part 503 are met when
the sewage sludge prepared hy the
person is applied to the land, placed on
a surface disposal site, or fired in a
sewage sludge incinerator. The preparer
could be the person who generates
sewage sludge during the treatment of
domestic sewage in a treatment works or
a person who derives a material derived
from sewage sludge. Examples of a
person who derives a material from
sewage sludge are a treatment works
that blends sewage sludge with some
other material or a private contractor
who receives sewage sludge from a
treatment works and then blends the
sewage sludge with some other material
(e.g., mixes the sewage sludge with a
bulking agent). When sewage sludge is
part of a material, the person derived
the material from sewage sludge. Any
time the quality of sewage sludge is
changed, a material is derived from
sewage sludge.
The purpose of this general provision
is to ensure the part 503 requirements
are met. The Agency concluded that the
person who generates the sewage sludge
or the person who derives a material
from sewage sludge should be
responsible for ensuring the sewage
sludge is used or disposed properly. For
this reason, the final part 503 regulation
makes that person responsible for
ensuring the applicable part 503
requirements are met when sewage
sludge prepared by the person is
applied to the land, placed on a surface
disposal site, or fired in a sewage sludge
incinerator. This is discussed further in
part XII of today's preamble.
Sampling and Analysis (Section 503.8)
This section of the final part 503
regulation requires that representative
samples of sewage sludge applied to the
land, placed on a surface disposal site,
or fired in a sewage sludge incinerator
be collected and analyzed. The purpose
of this requirement is to ensure that
samples of sewage sludge that are
collected are representative of the
sewage sludge that is used or disposed.
In some cases, grab samples may
represent the sewage sludge adequately
while in other cases a composite sample
may have to be collected. Whatever the
situation, a representative sample must
be collected and that sample must be
analyzed to show compliance with the
part 503 requirements.
This section also contains the
methods used to analyze representative
samples of sewage sludge to show
compliance with the part 503
requirements. Analytical methods are
specified in part 503 for enteric viruses,
fecal coliform, helminth ova, inorganic
pollutants, Salmonella sp. bacteria,
specific oxygen uptake rate, and total,
fixed, and volatile solids. In addition,
part 503 references a document that
contains procedures that can be used to
calculate the percent volatile solids
reduction for a sewage sludge. This
document, "Environmental Regulations
and Technology-Control of Pathogens
and Vectors, EPA-625/R-92/013, U.S.
-------
9326 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Environmental Protection Agency,
Washington, D.C., 1992, also discusses
how to collect samples that are analyzed
for pathogens.
Analytical methods in the final
regulation are the same as the analytical
methods in the part 503 proposal,
except for inorganic pollutants and
viable helminth ova. The numbers of the
parts in "Standard Methods for the
Examination of Water and Wastewater"
referred to in the final regulation for
various parts are different from the
numbers for those parts in the proposal
because a later edition of that document
was referenced in the final regulation.
Even though the part numbers are
different, the methods are the same.
The final rule specifies that Method
SW-846 be used to analyze samples of
sewage sludge for inorganic pollutants.
This method is used to prepare
sediment, sludge, and soil samples for
analysis by flame or furnace atomic
absorption spectroscopy. The Agency
decided to specify this method instead
of the method in the proposal (i.e.,
Method 1620 from the Analytical
Methods for the National Sewage Sludge
Survey) because Method SW-846 is
more widely accepted than is Method
1620, which is a draft method.
The analytical method for viable
helminth ova in the final regulation is
different from the analytical method for
helminth ova in the proposal. EPA
considers the proposed and final ova
methods to bo conceptually similar
when floatation or similar techniques
ore used to separate ova from the sewage
sludge. Both the proposed and final
methods use microscopic ova particle
visualization and characterization to
enumerate the helminth ova after the
sewage sludge is processed for analysis.
The ova method in the final regulation
was selected because it is more current
that the proposed method and is more
accepted in current practice.
General Definitions (Section 503.9)
Definitions included in this section of
the part 503 regulation are applicable to
more than one subpart in the regulation.
Each subpart also includes special
definitions that apply only to that
subpart.
Many of the definitions in this
subpart are definitions taken either
directly from section 502 of the CWA or
other Agency regulations. These
definitions are not discussed here. The
definitions developed specifically for
this rule are discussed below.
Domestic septage. Domestic septage is
either liquid or solid material removed
from a septic tank, cesspool, portable
toilet, Type III marine sanitation device,
or similar treatment works that receives
only domestic sewage. The term
"domestic septage" is used in the final
part 503 regulation instead of the term
"septage", which was used in the
proposed part 503 regulation, to
distinguish domestic septage from
liquid or solid material that contains
domestic septage mixed with other
materials (e.g., grease from a grease
trap). These other materials are
commercial or industrial septage and
are not included in the definition of
domestic septage.
The definition of domestic septage
also makes it clear that domestic septage
includes liquid and solid material
removed from portable toilets or Type
in marine sanitation devices. When
these materials are applied to
agricultural land, forest, or a
reclamation site, the domestic septage
requirements in the land applications
subpart have to be met. When these
materials are placed on an active sewage
sludge unit, the appropriate
requirements in the surface disposal
subpart have to be met.
Domestic sewage. Domestic sewage is
waste and wastewater from humans or
household operations that is discharged
to or otherwise enters a treatment
works. This is a key definition because
the standards in the part 503 regulation
apply to sewage sludge generated during
the treatment of domestic sewage in a
treatment works. When domestic
sewage is in the influent to a treatment
works, even if the influent also contains
industrial wastewater, sewage sludge is
generated during the treatment of the
domestic sewage.
Dry weight basis. Dry weight basis
means calculated on the basis of having
been dried at 105 degrees Celsius until
reaching a constant mass (i.e.,
essentially 100 percent solids content).
This definition is in the final part 503
regulation because all of the numerical
limits and operational standards in the
part 503 regulation are on a dry weight
basis. The dry weight basis allows an
"apples to apples" comparison of the
value for a parameter in sewage sludge
to the numerical limit or operational
standard in the part 503 regulation for
that parameter. The procedure used to
convert wet weight to dry weight varies
depending on the type of unit
measurement. For example, to convert a
wet weight concentration (i.e.,
milligrams per liter) to a dry weight
concentration, divide the wet weight
concentration by the percent solids
(expressed in hundredths) in the sewage
sludge. To convert an application rate
(i.e., metric tons per hectare) expressed
in wet weight to a dry weight
application rate, multiply the wet
weight rate by the percent solids
(expressed in hundredths) in the sewage
sludge.
Feed crops. Feed crops are crops
produced primarily for consumption by
animals. These include, but are not
limited to, corn and grass. Note that for
a crop to be considered a feed crop, it
has to be produced for consumption by
animals. A crop such as grass that is not
produced primarily for consumption by
animals (e.g., grass grown to prevent
erosion or to stabilize an area or as a
cover) is not a feed crop. The term
animals includes domestic animals and
wild animals. The key to this definition
is whether the crop is produced for
consumption by animals.
Fiber crops. Fiber crops are crops
such as flax and cotton. This definition
is included in the final part 503
regulation because products from these
crops (e.g., cotton seed oil) may be
consumed by humans or may be used to
prepare food consumed by humans.
Because of the potential exposure to the
fiber crop or product of the fiber crop,
the Agency concluded that the part 503
requirements should apply when
sewage sludge is applied to land on
which a fiber crop is grown.
Food crops. Food crops are crops
consumed by humans. These include,
but are not limited to, fruits, vegetables,
and tobacco. Tobacco is considered a
food crop, even though usually not
ingested by humans, because of the
potential for direct human exposure to
tobacco. Because of this exposure, the
Agency determined that the part 503
requirements must be met when sewage
sludge is applied to land on which
tobacco is grown. Food crops can be
either crops grown below the land
surface, crops that touch the land
surface, or crops that do not touch the
land surface. When a crop is consumed
by humans, it is a food crop.
Ground water. Ground water is water
below the land surface in the saturated
zone. The saturated zone is that part of
the earth's crust in which all voids in
the porous materials are filled with
water. The water that fills those voids is
ground water.
Person who prepares sewage sludge.
A person who prepares sewage sludge is
either the person who generates the
sewage sludge during the treatment of
domestic sewage in a treatment works or
a person who derives a material from
sewage sludge. This definition is
included in the final part 503 regulation
because the regulation contains a
general provision that requires any
person who prepares a sewage sludge to
ensure that the requirements in the part
503 regulation are met. This general
provision applies only when the sewage
sludge prepared by a person (i.e., the
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9327
sewage sludge generated by a person or
the material derived from sewage
sludge) is applied to the land, placed on
a surface disposal site, fired in a sewage
sludge incinerator, or placed on a
municipal solid waste landfill. Other
requirements for a person who prepares
sewage sludge also are included in the
final part 503 regulation.
Pollutant. A pollutant is an organic
substance, an inorganic substance, a
combination of organic and inorganic
substances, or a pathogenic organism
that, after discharge and upon exposure,
ingestion, inhalation, or assimilation
into an organism either directly from the
environment or indirectly by ingestion
through the food-chain, could, on the
basis of information available to the
Administrator of EPA, cause death,
disease, behavioral abnormalities,
cancer, genetic mutations, physiological
malfunctions (including malfunction in
reproduction), or physical deformations
in either organisms or offspring of the
organisms. This definition is similar to
the definition of "toxic pollutant"
included in section 502(13) of the CWA,
as amended.
The term "toxic pollutant" is not used
in the final part 503 regulation because
this generally is limited to the list of
priority toxic pollutants developed by
EPA. The Agency concluded that
Congress intended that EPA develop the
part 503 pollutant limits for a broader
range of substances that might interfere
with the use or disposal of sewage
sludge, not just the 126 priority toxic
pollutants.
Sewage sludge. The definition of
sewage sludge in the part 503 regulation
is similar to the definition in the
proposed part 503 regulation. Besides
editorial changes, the major differences
between today's definition and the
definition of sewage sludge in the part
503 proposal concern domestic septage
and materials not considered sewage
sludge.
The final part 503 regulation defines
sewage sludge as solid, semi-solid, or
liquid residue generated during the
treatment of domestic sewage in a
treatment works. Sewage sludge
includes, but is not limited to, domestic
septage; scum and solids removed in
primary, secondary, or advanced
wastewater treatment processes; and a
material derived from sewage sludge.
Sewage sludge does not include ash
generated during the incineration of
sewage sludge or grit and screenings
generated during preliminary treatment
of domestic sewage in a treatment
works.
Domestic septage is included in the
definition of sewage sludge because it is
generated during the treatment of
domestic sewage in a treatment works
(e.g., septic tank). It also has
characteristics similar to the
characteristics of sewage sludge. The
legislative history of section 405 reflects
congressional intent that the section
405(d) requirements apply to domestic
septage. S. Rep. No. 50, 99th Cong. 1st
Sess. p. 47 (1985). The term "domestic
septage" distinguishes domestic septage
from septage, which includes
commercial and industrial septage (e.g.,
grease from grease traps).
Scum is the material that floats on top
of the wastewater in a treatment process
and is removed by skimming. Scum
shares many characteristics with the
other residues generated during the
treatment of wastewater and often is
disposed with sewage sludge. For this
reason, scum is included in the
definition of sewage sludge.
Today's definition of sewage sludge
also indicates that any material derived
from sewage sludge (e.g., composted
sewage sludge blended with another
material) is sewage sludge. When that
material is used or disposed through
one of the practices regulated in the
final part 503 regulation, the
requirements for that practice must be
met.
Ash generated during the incineration
of sewage sludge is not included in
today's definition of sewage sludge.
Incinerator ash, which is disposed
typically in landfills, is sterile and dry
like other ash material. It does not have
the same characteristics as other
residues from wastewater treatment
processes.
Grit and screenings also are not
included in the definition of sewage
sludge. Grit is the material, such as sand
and gravel, that settles out before
primary treatment. Screenings are
relatively large pieces of solid material
caught on bar screens at the headworks
of the treatment works. These wastes are
small in quantity; have characteristics
that are different from the
characteristics of sewage sludge; and
usually are handled and disposed
separately.
Storage of sewage sludge. Storage of
sewage sludge is the placement of
sewage sludge on land on which the
sewage sludge remains for two years or
less. Storage does not include placement
of sewage sludge on the land for
treatment.
An issue related to the definition of
storage of sewage sludge concerns the
length of time (i.e., two years) sewage
sludge is stored before storage becomes
final disposal. The length of time can be
expressed in two ways. First, the period
of time can be related to how long the
land is used for the storage of sewage
sludge. It is difficult to define storage in
terms of the length of time the land is
used to store sewage sludge because the
land may be used to store sewage sludge
for a long period of time even though a
particular sewage sludge only remains
on the land for a short period of time
(e.g., 120 days).
The second way to express length of
time for storage is the age of the sewage
sludge on the unit area of land. The
Agency determined that this parameter
is more appropriate to use to distinguish
between storage and final disposal than
is the period of time the land is used to
store sewage sludge. The older the
sewage sludge, the higher the potential
that the sewage sludge may cause an
adverse impact.
The definition of storage in today's
final part 503 regulation does not
indicate whether the two year storage
period is the period the land is used to
store sewage sludge or the age of the
sewage sludge. Either parameter can be
used to define the storage period.
Treatment of sewage sludge.
Treatment of sewage sludge is the
preparation of sewage sludge for final
use or disposal. This includes, but is not
limited to, thickening, stabilization, and
dewatering of sewage sludge. Treatment
of sewage sludge is not storage of
sewage sludge.
This definition is included in the part
503 regulation to distinguish treatment
from final use or disposal. Requirements
in the part 503 regulation apply to
sewage sludge that is used or disposed.
For this reason, when the sewage sludge
is treated, the part 503 standards do not
apply to the sewage sludge, except
when treated for pathogen or vector
attraction reduction, or, in the case
where land is used to treat the sewage
sludge, to the land on which sewage
sludge is treated.
Treatment works. Treatment works is
either a Federally owned, publicly
owned, or privately owned device or
system used to treat (including recycle
and reclaim) either domestic sewage or
a combination of domestic sewage and
industrial waste of a liquid nature. This
includes septic tanks and other types of
on-site treatment systems and holding
tanks because domestic sewage can be
treated in these types of devices. Note
that, by definition, devices or systems
used to treat a combination of domestic
sewage and industrial waste of a liquid
nature are a treatment works. Sludge
generated by the treatment works is
sewage sludge.
Land Application (Subpart B)
This part of the preamble discusses
the part 503 requirements for land
application of sewage sludge. More
-------
9328 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
details on each of the requirements can
be found in the technical support
document for the part 503 land
application requirements.
The final regulation recognizes two
broad categories of sewage sludge
applied to the land and establishes
requirements for each category. For both
categories, the sewage sludge must meet
ceiling concentrations. If those
concentrations ore not met, the sewage
sludge cannot be applied to the land.
The first category is bulk sewage
sludge applied to the land. Bulk sewage
sludge is sewage sludge that is not sold
or given away in a bag or other
container. Bulk sewage sludge must
meet one of two pollutant limits to be
applied to the land. The sewage sludge
must moot pollutant concentration
limits, which ore in addition to the
ceiling concentrations discussed above,
or the amount of a pollutant applied to
the land in bulk sewage sludge must not
exceed a cumulative pollutant loading
rate. In addition, pathogen and vector
attraction reduction requirements must
bo met when bulk sewage sludge is
applied to the land. General
requirements and management practices
also may have to be met when bulk
sowogo sludge is applied to the land
depending on the quality of the bulk
sewage sludge.
The second category is sewage sludge
sold or given away in a bag or other
container for application to the land.
One of two pollutant limits also must be
mot when sewage sludge is sold or given
away in a bag or other container. The
sewage sludge must meet the same
pollutant concentrations mentioned
above for bulk sewage sludge, or the
amount of pollutant applied to the land
annually must not exceed an annual
pollutant loading rate. The annual
pollutant loading rates are used to
calculate an application rate that is
placed on a label on the bag or other
container in which the sewage sludge is
sold or given away. The application rate
cannot be exceeded when the sewage
sludge is applied to the land. In
addition to meeting the pollutant limits,
the sewage sludge must meet the highest
quality pathogen requirements (i.e.,
Class A requirements) and a vector
attraction reduction requirement must
bo mot. Sewage sludge sold or given
away in a bag or other container also is
subject to general requirements and a
management practice depending on the
quality of the sewage sludge.
Applicability (Section 503.10)
The applicability section for land
application in the proposed part 503
regulation indicated that the
requirements apply to the application of
sewage sludge to the land and to any
person who applies sewage sludge to
land. That section has been edited to be
more explicit. The final part 503
regulation indicates that the land
application requirements apply to any
person who prepares sewage sludge that
is applied to the land, to any person
who applies sewage sludge to the land,
to sewage sludge applied to the land,
and to the land on which sewage sludge
is applied.
Some of the requirements in this
subpart apply to the sewage sludge that
is land applied. These requirements
address the quality of sewage sludge
applied to the land and the amount of
pollutants that can be applied to the
land in sewage sludge.
Other requirements in this subpart
apply to a person who prepares sewage
sludge that is applied to the land. A
person who prepares sewage sludge is
either the generator of the sewage sludge
or a person who derives a material from
sewage sludge. Still other requirements
apply to the person who applies sewage
sludge to the land (e.g., recordkeeping
requirements depending on which
pollutant limits are met). All of these
requirements are discussed in more
detail later in this preamble.
As mentioned previously, the part 503
use or disposal standards include
general requirements, pollutant limits,
management practices, operational
standards, and requirements for
frequency of monitoring, recordkeeping,
and reporting. For land application of
sewage sludge, there are three cases
where not all requirements must be met
to comply with the standards. These
three cases concern bulk sewage sludge
applied to the land and sewage sludge
sold or given away in a bag or other
container for application to the land.
In the first two cases, the sewage
sludge or material derived from sewage
sludge must meet certain pollutant
limits and certain operational standards
for pathogens and vector attraction
reduction. In addition, the frequency of
monitoring, recordkeeping, and
reporting requirements in the land
application subpart must be met. The
general requirements and management
practices do not apply when the sewage
sludge or material derived from sewage
sludge meets the three quality
requirements.
The rationale for not imposing the
general requirements and management
practices on bulk sewage sludge and
sewage sludge sold or given away in a
bag or other container for application to
the land is that the sewage sludge that
meets the three identified quality
requirements is a valuable commercial
product. Because of this, EPA
concluded that the probability of
improper application of the sewage
sludge is low and the additional
requirements are not necessary to
protect public health and the
environment. In addition, the Agency
determined that over-application of the
sewage sludge will not occur because
over-application reduces crop yield,
which nullifies the main reason to apply
sewage sludge to the land in the first
instance. The Agency concluded that
when the sewage sludge meets the three
quality requirements, it is a fertilizer
material and should be treated similarly
to other fertilizers. For these reasons,
EPA does not require that the general
requirements and management practices
be met when high quality sewage
sludges are applied to the land. The
circumstances in which these
requirements need not be met are
discussed further below.
For both the first and second cases,
the EPA Regional Administrator (or, in
the case of a State with an approved
sludge management program, the State
Director) could still, acting under
authority in section 405(d)(4), decide to
require that any or all of the general
requirements and management practices
be met, on a case-by-case basis, even
when a sewage sludge or bulk material
derived from sewage sludge meets the
three quality requirements. However,
this requires a finding by the Regional
Administrator that the general
requirements or management practices
are needed to protect public health and
the environment from any reasonably
anticipated adverse effect of a pollutant
in the sewage sludge.
An example of a management practice
that could be imposed is the
requirement to apply the sewage sludge
or material derived from sewage sludge
to the land at a whole sludge
application rate (i.e., the amount of
sewage sludge that can be applied to an
area of land) that does not exceed the
agronomic rate. When the Regional
Administrator concludes this
requirement is needed to protect public
health and the environment from the
reasonably anticipated adverse effect of
nitrogen in the sewage sludge, the
Regional Administrator could impose
that requirement to the bulk sewage
sludge. Under this provision, the control
over the site where the sewage sludge is
applied, which was foregone because of
the general requirements and
management practices do not apply,
may be re-established.
In the third case, the part 503
requirements in the land application
subpart do not apply to a bulk material
derived from sewage sludge when the
sewage sludge used to produce the
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9329
derived material meets the pollutant
concentrations in 503.13(b)(3), the Class
A pathogen requirements in 503.32(a),
and one of the vector attraction
reduction requirements in 503.33(b)(l)
through 503.33(b)(8). In this case, the
sewage sludge used to produce the bulk
material already meets the three quality
requirements.
The final part 503 regulation does not
authorize the EPA Regional
Administrator or the State Director to
impose the general requirements and
management practices on a bulk
material derived from a sewage sludge
that meets the three quality
requirements because the part 503
requirements do not apply to sewage
sludge used to make that material once
the sewage sludge meets the identified
quality requirements. No records have
to be kept on who receives that sewage
sludge or what happens to the sewage
sludge after the three quality
requirements are met.
The three cases for sewage sludge sold
or given away in a bag or other
container for application to the land are
the same as the three cases for bulk
sewage sludge applied to the land. In
the first two cases, the general
requirements in 503.12 and the
management practices in 503.14 do not
apply either to sewage sludge or a
material derived from sewage sludge
when the sewage sludge or material is
sold or given away in a bag or other
container for application to the land and
when the sewage sludge or material
meets the pollutant concentrations for
high quality sewage sludges in
503.13(b)(3), the more stringent Class A
pathogen requirements in 503.32(a), and
one of the vector attraction requirements
in 503.33(b)(l) through 503.33(b)(8).
The frequency of monitoring,
recordkeeping, and reporting
requirements in this subpart do apply,
however, to the sewage sludge or
material derived from sewage sludge.
In the third case, the final part 503
regulation indicates that the part 503
requirements do not apply to a material
derived from sewage sludge that is sold
or given away in a bag or other
container when the sewage sludge used
to derive that material meets the
pollutant concentrations for high quality
sewage sludges in 503.13(b)(3), the more
stringent Class A pathogen requirements
in 503.32(a), and one of the vector
attraction requirements in 503.33(b){l)
through 503.33(b)(8). The sewage sludge
used to derive that material already
meets the applicable quality
requirements.
The provision authorizing the
imposition of the general requirements
and management practices after a
sewage sludge or material derived from
sewage sludge meets the three quality
requirements does not apply to sewage
sludge sold or given away in a bag or
other container for application to the
land. As mentioned above, this
provision in part allows control over the
site where the sewage sludge is applied
to be re-established. The underlying
assumption for sewage sludge sold or
given away in a bag or other container
is that there is no direct control over the
user of the sewage sludge. It is virtually
impossible in the case of a widely
distributed sewage sludge that is
essentially equivalent to fertilizer to
impose controls on the end user of the
sewage sludge. When there is no control
over the user initially, there is no way
to re-establish that control through the
imposition of general requirements or
management practices. For this reason,
the provision concerning re-imposing
certain requirements is not applicable in
this case.
Special Definitions (Section 503.11)
In this section of the final part 503
regulation, the Agency defines terms
used in this subpart. Those terms
include: agricultural land, agronomic
rate, annual pollutant loading rate,
annual whole sludge application rate,
bulk sewage sludge, cumulative
pollutant loading rate, forest, land
application, other container, pasture,
public contact site, range land, and
reclamation site.
Agricultural land. Agricultural land is
land on which a food crop, a feed crop,
or a fiber crop is grown. This includes
range land and land used as pasture.
When the crop grown on the land is not
consumed by humans; not produced
primarily for consumption by animals;
or not a fiber crop, the land on which
the crop is grown is not agricultural
land.
Range land and pasture are included
in the definition of agricultural land
because feed crops (e.g., grasses and
other types of vegetation) are grown on
the land. These crops are consumed by
animals that graze on the land.
Agronomic rate. Agronomic rate is
defined as the whole sludge application
rate designed: (1) to provide the amount
of nitrogen needed by the crop or
vegetation grown on the land and (2) to
minimize the amount of nitrogen in the
sewage sludge that passes below the
root zone of the crop or vegetation
grown on the land to the ground water.
A key aspect of this definition is the
design of the whole sludge application
rate. To design this rate, the nitrogen
needs of the crop or vegetation grown
on the land, the available nitrogen in the
sewage sludge, the soil conditions at the
site, and the geology of the site have to
be known, among other things.
Agronomic rate is used in the final
part 503 regulation to limit the amount
of sewage sludge applied to the land to
fertilize the crop or vegetation grown on
the land. The purpose of limiting the
application rate to the agronomic rate is
to minimize contamination of the
ground water beneath the application
site by the nitrogen in the sewage
sludge.
Annual pollutant loading rate. The
annual pollutant loading (APLR) is the
maximum amount of a pollutant that
can be applied to a unit area of land
during a 365-day period. In the final
part 503 regulation, this rate is
calculated by dividing the cumulative
pollutant loading rate for an inorganic
pollutant by 20 years. This is discussed
further below.
Annual whole sludge application rate.
The annual whole sludge application
rate (AWSAR) is the maximum amount
of sewage sludge on a dry weight basis
that can be applied to a unit area of land
during a 365-day period. This rate is for
the whole sludge and not just for a
single pollutant. An explanation of how
to calculate an annual whole sludge
application rate is in appendix A of the
final regulation.
Bulk sewage sludge. Bulk sewage
sludge is sewage sludge that is not sold
or given away in a bag or other
container for application to the land.
This definition is included in the final
part 503 regulation because the
requirements in this subpart differ for
bulk sewage sludge and for sewage
sludge sold or given away in a bag or
other container for application to the
land.
Cumulative pollutant loading rate. A
cumulative pollutant loading rate is the
maximum amount of an inorganic
pollutant that can be applied to an area
of land. This loading rate is not an
annual rate. Rather, it is the maximum
amount of an inorganic pollutant that
can be applied to an area of land. When
the cumulative pollutant loading rate for
a pollutant is reached for a particular
land application site, no more of that
pollutant can be applied to the site in
bulk sewage sludge.
Forest. Forest is a tract of land thick
with trees and underbrush. A forest
includes, but is not limited to, land used
for silviculture purposes and
unmanaged land thick with indigenous
vegetation.
Land application. Land application is
the spraying or spreading of sewage
sludge onto the land surface; the
injection of sewage sludge below the
land surface; or the incorporation of
sewage sludge into the land so that the
-------
9330 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sowago sludge can either condition the
soil or fertilize crops or vegetation
grown in the soil. One important aspect
of this definition is"* * * so that the
sowogQ sludge can condition the soil or
fertilize crops or vegetation grown on
the land." Sewage sludge is not
disposed on the land in this case.
Rather, the sewage sludge is used
beneficially.
The definition of land application
includes such things as using the
sewage sludge to grow plants or flowers
in a pot and using sewage sludge in the
hole whore a tree is planted. In such
cases, the sewage sludge is used to
fertilize the plant or tree even though
the sewage sludge is not spread over a
large area of land. Sewage sludge used
for those purposes must meet the
applicable requirements in the land
application subpart of the final part 503
regulation.
when the sewage sludge is not used
to condition the soil or to fertilize crops
or vegetation grown on the land, the
sewage sludge is not being land applied.
It is being disposed on the land. In that
case, the requirements in the subpart on
surface disposal in the final part 503
regulation must be met.
Other container. The part 503
regulation differentiates between sewage
sludge sold or given away in large
quantities to users such as
manufacturers of sewage sludge
fertilizer products and sewage sold or
given away in a bag or other container
for direct use by the purchaser or
receiver of the sewage sludge. Thus, the
part 503 regulation distinguishes
between bulk sewage sludge and sewage
sludge sold or given away in a bag or
other container. An "other container" is
either an open or a closed receptacle
and may include, but is not limited, to
a bucket, a box, a carton, or a vehicle
that has a load capacity of one metric
ton or less.
An "other container" could be any
type of receptacle in which sewage
sludge, usually in small amounts, is
sold or given away for application to the
land. In most cases, the sewage sludge
is used to fertilize a lawn or a home
garden; to grow flowers in pots; to
fertilize the ball of a tree that is planted,
or for a similar type use. The sewage
sludge usually is not applied to those
typos of land in several applications in
the same year.
The Agency also chose to include in
the definition of "other container" a
vehicle that has a load capacity of one
metric ton or less. The vehicle could be,
among other things, a pick-up truck or
a trailer pulled by an automobile.
A vehicle load capacity of one metric
ton was chosen as the cut-off because of
the assumptions EPA used to develop
the standards for sewage sludge sold or
given away in a bag or other container
for application to the land. The Agency
assumed that sewage sludge sold or
given away is applied to the land in
small amounts and that the sewage
sludge is not applied to the land in
several applications in the year,
EPA considers one metric ton of
sewage sludge to be a small amount,
particularly considering the types of
land on which the Agency concluded
that is sold or given away will be
applied (i.e., a lawn, a home garden, or
a public contract site). In addition, EPA
does not believe that a vehicle with a
load capacity of one metric ton or less
will be used to haul the amount of
sewage sludge needed on other types of
land (e.g., agricultural land) and that
such a vehicle will not be used to make
several trips to the same site,
particularly for several applications of
sewage sludge. Most likely, a vehicle
with a load capacity of one metric ton
will be used to haul sewage sludge that
is applied to a lawn, a home garden, or
a public contact site.
Pasture. Pasture is land on which
animals feed directly on feed crops such
as legumes, grasses, grain stubble, or
stover. For the purpose of the final part
503 regulation, pasture is considered
agricultural land because a feed crop is
grown on the land.
Public contact site. A public contact
site is land with a high potential for
contact by the public. Included in this
type of land are public parks, ball fields,
cemeteries, plant nurseries, turf farms,
and golf courses. All of these lands have
a high potential for contact by the
public. This definition is included in
part 503 because the final regulation
contains specific requirements for
sewage sludge applied to a public
contact site.
Range land. Range land is open land
with indigenous vegetation. This type of
land differs from a forest in that range
land is more open. Range land has
indigenous vegetation, but is not thick
with trees and underbrush.
Reclamation site. A reclamation site is
drastically disturbed land that is
reclaimed using sewage sludge. The
drastically disturbed land may be a strip
mine, a construction site, or some other
land that has been cleared of most of its
vegetation. Sewage sludge is applied to
the land to help establish vegetation.
The sewage sludge provides organic
material and nutrients needed for the
vegetation to grow.
General Requirements (Section 503.12)
The proposed regulation contained
six general requirements for land
application of sewage sludge. Two of
those general requirements are
addressed in the general requirements
in the final regulation (i.e., meet the
requirements in this subpart when
sewage sludge is applied to the land and
provide notice and information when
the generator of the sewage sludge is not
the applier of the sewage sludge), two
are management practices in the final
regulation (i.e., those concerning
threatened and endangered species and
application of sewage sludge to flooded,
snow-covered, or frozen land), one is
now addressed in the frequency of
monitoring requirement in the final
regulation (i.e., comply with the
monitoring requirements), and one was
deleted from the final regulation.
The proposed general requirement
that was deleted from the final
regulation concerns restricting the flow
of a base flood, reducing the temporary
storage capacity of a floodplain, or
posing a hazard to human health,
wildlife, or land or water resources
because of sewage sludge in the runoff
from the base flood. When sewage
sludge is applied to the land, it is
applied in large amounts over while
areas. The sewage sludge is not piled
high on the land in a small ares. In this
case, the sewage sludge cannot restrict
the flow of a base flood or reduce the
temporary storage capacity of a
floodplain. In addition, pollutant limits
in the land application subpart are
designed to protect run-off of pollutants
into surface waters (i.e., the surface
water pathway was evaluated during the
land application exposure assessment).
For these reasons and because the
probability that sewage sludge will be
land applied to a 100-year floodplain is
low, the Agency concluded that this
general requirement is not needed in the
final regulation (it would be a
management practice if included in the
final regulation) to protect public health
and the environment when sewage
sludge is applied to the land.
There are 10 general requirements for
land application of sewage sludge in the
final part 503 regulation. The first
general requirement is that no person
shall apply sewage sludge to the land
except in accordance with the
requirements in this subpart. This
general requirement is an explicit
statement of obligation not to violate the
requirements in this subpart when
sewage sludge is applied to the land.
The second general requirement
indicates that no person shall apply
bulk sewage sludge subject to the
cumulative pollutant loading rates in
503.13(b)(2) to land where any of the
cumulative pollutant loading rates have
been reached. This general requirement
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9331
establishes an explicit requirement not
to exceed any of the cumulative
pollutant loading rates at a land
application site. It does not apply when
the sewage sludge meets the pollutant
concentrations in 503.13(b)(3).
The third general requirement
concerns the application of domestic
septage to agricultural land, forest, or a
reclamation site. A person may not
apply domestic septage to those types of
land during a 365-day period when the
annual application rate for domestic
septage in 503.13(c) has been reached
during that period. This general
requirement does not apply to a public
contact site because the final part 503
regulation prohibits the application of
domestic septage to a public contact site
at the annual application rate in
503.13(c).
The fourth general requirement
concerns providing the concentration of
total nitrogen (as N on a dry weight
basis) in bulk sewage sludge to the
person who applies the bulk sewage
sludge to the land. The person who
prepares the bulk sewage sludge is
required to provide the applier written
notification of the nitrogen
concentration in the bulk sewage
sludge, except for the bulk sewage
sludge and bulk material that meet the
three quality requirements discussed
above. The purpose of this general
requirement is to ensure that the person
who applies the bulk sewage sludge is
aware of the nitrogen concentration in
the bulk sewage sludge. Without that
concentration, the agronomic rate for
the crop grown on the land application
site cannot be designed properly.
The fifth general requirement requires
any person who applies sewage sludge
to the land to obtain the information
needed to comply with the part 503
requirements. This general requirement
establishes an explicit requirement for
the person who applies the sewage
sludge to become aware of the
requirements (e.g., site restrictions when
the sewage sludge meets the less
stringent Class B pathogen
requirements) that must be met when
sewage sludge is applied to the land.
This is a logical extension of the part
503 requirements because without the
information a person cannot comply
with those requirements.
The fifth general requirement also
contains more detailed requirements for
the applier when the bulk sewage
sludge meets the pollutant ceiling
concentrations in 503.13(b)(l) and is
applied to a site under the cumulative
pollutant loading rate concept in
503.13(b)(2). In that case, the applier
must contact the permitting authority in
the State where the bulk sewage sludge
will be applied to determine whether
bulk sewage sludge subject to the
cumulative pollutant loading rates has
been applied to the site since [insert 120
days after the effective date of this part].
Note that the purpose of contacting the
permitting authority is to determine
whether bulk sewage sludge subject to
the above requirements has been
applied to the site and not to determine
the amount of each pollutant applied to
the site in bulk sewage sludge.
When results of the above search
indicate that bulk sewage sludge subject
to the cumulative pollutant loading
rates has not been applied to the site,
the cumulative amount of each
pollutant in Table 2 of section 503.13 of
the final regulation can be applied to the
site. In this case, the applier must keep
a record of the amount of each pollutant
in the bulk sewage sludge applied to the
site by the applier.
When results of the above search
indicate that bulk sewage sludge subject
to the cumulative pollutant loading
rates has been applied to the site since
[insert 120 days after the effective date
of this part], the applier must look for
the records of the amount of each
pollutant applied to the site in bulk
sewage sludge since that date. When
those records are available, the applier
must use that information to determine
the additional amount of each pollutant
that can be applied to the site so as not
to violate the cumulative pollutant
loading rate for the pollutant. In this
case, the applier must keep the records
of the amount of each pollutant applied
previously by other appliers and also
must keep a record of the amount of
each pollutant in the bulk sewage
sludge the applier applies to the site.
When the records of the amount of each
pollutant applied previously cannot be
found, an additional amount of each
pollutant cannot be applied to the site
in bulk sewage sludge because that may
violate the cumulative pollutant loading
rate for the pollutant.
One purpose of the last part of the
fifth general requirement is to ensure
that only the permissible total quantity
for each pollutant is applied to a site in
bulk sewage sludge after [insert 120
days after the effective date of this part].
Without knowing the previous amounts
applied, this requirement cannot be met.
Note that the requirements to contact
the permitting authority and search for
records, if appropriate, apply only when
bulk sewage sludge subject to the
cumulative pollutant loading rates is
applied to the land. These requirements
do not apply when the bulk sewage
sludge that meets the high quality
pollutant concentrations in 503.13(b)(3)
is applied to the land.
Another purpose of the last part of the
fifth general requirement is to prevent
two people from applying bulk sewage
sludge to the same site without either
person knowing the amount of each
pollutant listed in Table 2 of section
503.13 that the other person applies to
the site in bulk sewage sludge. Under
this general requirement, all persons
who apply bulk sewage sludge subject
to cumulative pollutant loading rates to
a site must contact the permitting
authority to determine whether bulk
sewage sludge subject to that
requirement has been applied to a site
since [insert 120 days after the effective
date of this part].
In the proposed regulation, EPA
included requirements for the owner/
operator of a treatment works to keep
records of the amount of inorganic
pollutants applied to each site (54 FR
5745 at 5895). The purpose of that
requirement was to ensure that the
cumulative pollutant loading rates were
not violated at each land application
site. The final regulation has the same
requirement for the same reason: To
ensure no violation of the cumulative
pollutant loading rates.
In the final regulation, EPA extended
the requirements to keep records of the
amount of pollutants applied to a site in
bulk sewage sludge to landowners who
apply the bulk sewage sludge. This is a
logical extension of the need for
recordkeeping to prevent violations of
the cumulative pollutant loading rates.
The availability of the records to new
owners of the land (or the prohibition
on the application of bulk sewage
sludge to a site in its absence) is a
necessary measure to protect against
exceeding cumulative pollutant loading
rates on land application sites.
The sixth general requirement
concerns a person who prepares bulk
sewage sludge that is applied to the land
by a different person. In this case, the
person who prepares the bulk sewage
sludge (i.e., the generator of the sewage
sludge or the person who derives a
material from sewage sludge) must
provide notice and necessary
information to the person who applies
the bulk sewage sludge to the land to
comply with the part 503 requirements.
An example of the information that
should be provided is the site
restrictions that have to be met when
the sewage sludge meets the less
stringent Class B pathogen
requirements.
The seventh general requirement,
which is similar to the sixth general
requirement, addresses the situation
where the person who prepares sewage
sludge provides the sewage sludge to
another person who prepares the sewage
-------
9332
Federal Register / Vol. 58 No. 32 / Friday, February 19, 1993 / Rules and Regulations
sludge (e.g., the person derives a
material from the sewage sludge). In this
case, the person who prepares the
sewage sludge must provide the receiver
of the sewage sludge notice and
necessary information to comply with
the requirements in this part. An
example of when this general
requirement applies is when a person
receives sewage sludge from more than
one person who prepares sewage sludge
and then derives a material from the
sowoge sludges, either through mixing
of the bulk sewage sludges or some
other operation. In this situation, each
person who prepares sewage sludge
must provide the person who derives
the material information (e.g.,
information on the quality of the sewage
sludge) to comply with the requirements
in this subpart.
The eighth general requirement
requires the applier of the sewage
sludge to provide notice and necessary
Information to the owner or lease holder
of the land on which hulk sewage
sludge is applied to comply with the
requirements in the land application
subpart. The land owner or lease holder
has to know about requirements for the
land application site (e.g., site
restrictions when a sewage sludge
mooting the less stringent Class B
pathogen requirements is applied to the
land and management practices) to
ensure that those requirements are met.
This general requirement ensures that
the owner or lease holder of the land
receives that information. It only
applies, however, when bulk sewage
sludge is applied to the land. It does not
apply when sewage sludge sold or given
away In a bag or other container for
application to the land.
The ninth general requirement
addresses a notice that must be
provided when bulk sewage sludge,
except bulk sewage sludge meeting the
high quality requirements discussed
above, is transported across State lines
for land application in another State.
When bulk sewage sludge is generated
in one State (the generating State) and
transferred to another State (the
receiving State), the person who
prepares the bulk sewage sludge must
notify the permitting authority in the
receiving State in which the bulk
sowago sludge is proposed to be
applied. The permitting authority for
tho receiving State is the EPA Regional
Administrator or the State Director of
the receiving State when that State has
an approved sewage sludge program.
Note that there are no approved State
sludge programs as of the publication
date of part 503.
EPA adopted this requirement so that
the permitting authority can determine
whether a permit application, or other
appropriate oversight, for the land
application site is needed. The notice
must be given prior to transporting the
sewage sludge so that the permitting
authority has time to make this
determination. Generally, permit
applications are not required for land
application sites because they are not
automatically considered treatment
works treating domestic sewage. In a
May 2,1989, notice, EPA stated that
"under the Federal program, permits
will not be required for owners or
operators of land where sludge is
beneficially reused such as farm lands
and home gardens" (54 FR 18726)).
However, the Agency went on to say
that Part 122 contains a second part to
the definition of treatment works
treating domestic sewage that allows the
Regional Administrator to designate a
facility a treatment works treating
domestic sewage "where necessary to
protect public health and the
environment from poor sludge quality,
use, handling, or disposal practices, or
to ensure compliance with 40 CFR part
503" (54 FR 18726)). To determine
whether a permit, or other appropriate
oversight is necessary, the permitting
authority must first know that sewage
sludge will be applied to a site.
In the proposed regulation, EPA
required that the owner/operator of the
treatment works to keep the location of
the land application site and to submit
the location to the permitting authority
(54 FR 5745 at 5895). The requirement
in this general requirement to notify the
permitting authority when sewage
sludge is applied to land in a State other
than in the State where it is prepared
and to provide the permitting authority
the location of the land application site
is a logical outgrowth of the proposed
requirement to provide the permitting
authority the location of the land
application site.
The notice required by this general
requirement is a one-time notification
for each applier to any particular land
application site. The notice includes
information on the approximate time
period sewage sludge will be applied to
the site to preserve some flexibility as to
exactly when sewage sludge will be
applied to the site and to allow multiple
applications to the same site over a
period of time without requiring a
separate notice for each application.
In addition to the approximate time
period sewage sludge will be applied to
a site, the notice must include the
location of the site and information on
both the person who prepares the bulk
sewage sludge and the person who will
apply the bulk sewage sludge. The
permitting authority may request
additional information or a full permit
application as noted above. EPA does
not expect that many permits will be
issued to these land application sites.
This notice requirement provides the
permitting authority the flexibility to
impose additional requirements, if
needed, and to ensure compliance with
part 503.
The last general requirement also
addresses a notice that must be
provided. When bulk sewage sludge
subject to the cumulative pollutant
loading rates is applied to the land, the
person who applies the bulk sewage
sludge must notify the permitting
authority for the State in which the bulk
sewage sludge will be applied. This
must be done prior to the initial
application of bulk sewage sludge to a
site by each applier. The purpose of this
general requirement is to ensure that a
record is kept of the sites where sewage
sludge subject to the cumulative
pollutant loading rates is applied.
Without that information, there is no
way for a person who intends to apply
bulk sewage sludge to know whether
bulk sewage sludge has been applied to
a site previously. When it is not known
whether bulk sewage sludge subject to
cumulative pollutant loading rates has
been applied to a site, the cumulative
pollutant loading rates in 503.13(b)(2)
cannot be enforced. Note that this notice
only provides information about
whether bulk sewage sludge has been
applied to a site. It does not include the
amount of each pollutant applied to a
site in bulk sewage sludge. Once the
person who proposes to apply the bulk
sewage sludge determines that bulk
sewage sludge subject to cumulative
pollutant loading rates has been applied
to the site, that person must then
contact the previous appliers to
determine the amount of each pollutant
applied to the site previously in bulk
sewage sludge.
The notice required by the last general
requirement also is a one-time notice for
a land application site for each applier.
Information that must be provided in
the notice includes the location of the
land application site and the name,
address, telephone number, and
National Pollutant Discharge
Elimination System permit number, if
appropriate, of the person who will
apply the bulk sewage sludge.
Pollutant Limits (Section 503.13)
The final part 503 regulation contains
ceiling concentration (Table 1),
cumulative pollutant loading rates
(Table 2), pollutant concentrations
(Table 3), and annual pollutant loading
rates (Table 4). Any sewage sludge that
does not meet the ceiling concentrations
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9333
in Table 1 cannot be applied to the land.
Other pollutant limits also are included
in 503.13 for bulk sewage sludge and for
sewage sludge sold or given away in a
bag or other container. Bulk sewage
sludge that is applied to the land is
subject to cumulative pollutant loading
rates if the sewage sludge does not meet
the pollutant concentrations for high
quality sewage sludge. Sewage sludge
sold or given away in a bag or other
container is subject to annual pollutant
loading rates if it does not meet the
pollutant concentrations for high quality
sewage sludges.
Ceiling concentrations are included in
the final part 503 regulation because
EPA is concerned about the potential
impact of a "dirty" sewage sludge on
public health and the environment (e.g.,
phytotoxicity to plants). As mentioned
above, if the pollutant concentrations in
sewage sludge exceed the ceiling
concentrations, sewage sludge cannot be
applied to the land.
The ceiling concentrations in Table 1
are the less stringent of two values.
They are the concentrations calculated
using the cumulative pollutant loading
rules from the land application
exposure assessment, an assumed 100-
year site life, and an assumed annual
whole sludge application rate of 10
metric tons per year or the 99th
percentile concentration from the
National Sewage Sludge Survey (NSSS),
whichever is less stringent. EPA
concluded that when the pollutant
concentrations in the sewage sludge do
not exceed the ceiling concentrations,
the potential for short-term impacts on
the environment from land application
of the sewage sludge are reduced
greatly.
The final part 503 regulation contains
two pollutant limits for bulk sewage
sludge applied to the land. The first
limit for bulk sewage sludge applied to
the land consists of cumulative
pollutant loading rates. A cumulative
pollutant loading rate is the cumulative
amount of an inorganic pollutant that
can be applied to an area of land.
Cumulative pollutant loading rates must
be met when bulk sewage sludge that
does not meet the pollutant
concentrations for high quality sewage
sludge is applied to the land.
The final part 503 regulation requires
that the cumulative amount of each
pollutant listed in Table 2 of section
503.13 from bulk sewage sludge applied
to the land shall not exceed the
cumulative pollutant loading rate for the
pollutant in Table 2. To comply with
this requirement, the amount of each
pollutant in the bulk sewage sludge
applied to a site must be known.
Records have to be kept of the amount
of each pollutant applied to each site.
When the cumulative pollutant loading
rate for any of the pollutants in Table 2
of section 503.13 is reached for a site,
no more bulk sewage sludge may be
applied to that site. The ceiling
concentrations and cumulative
pollutant loading rates may be met
when bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site.
The following procedure can be used
to estimate site life for a bulk sewage
sludge with a particular quality and for
a certain annual whole sludge
application rate (AWSAR) when the
cumulative pollutant loading rates are
met. When either the quality of the bulk
sewage sludge or the AWSAR changes,
the site life for the land also changes.
Procedure
1. Measure the concentration of arsenic,
cadmium, chromium, copper, lead, mercury,
molybdenum, nickel, selenium, and zinc in
the bulk sewage sludge.
2. Determine the AWSAR for the bulk
sewage sludge. Usually, the AWSAR is equal
to the agronomic rate for the bulk sewage
sludge.
3. Calculate an annual pollutant loading
rate (APLR) for each inorganic pollutant
using equation (1) below.
APLR=CxAWSARx0.001 (1)
Where:
APLR=Annual pollutant loading rate for an
inorganic pollutant in kilograms-
pollutant per hectare per 365-day period.
C=Measured pollutant concentration in the
bulk sewage sludge in milligrams-
pollutant per kilogram of total solids (dry
weight basis).
AWSAR=Annual whole sludge application
rate in metric tons-sewage sludge per
hectare per 365-day period (dry weight
basis).
0.001=A conversion factor.
4. Calculate the years an inorganic
pollutant can be applied to the land by
dividing the cumulative pollutant loading
rate in Table 2 of the final regulation by the
APLR calculated from Step 3 of this
procedure.
5. Determine the lowest number of years
calculated in Step 4 of this procedure. This
is the period that this bulk sewage sludge can
be applied to the land without causing any
of the cumulative pollutant loading rates in
Table 2 of section 503.13 to be exceeded.
6. This procedure is used only to estimate
the number of years a bulk sewage sludge can
be applied to a site. This estimate changes
when the inorganic pollutant concentrations
in the bulk sewage sludge change or when
the annual whole sludge application rate
changes.
EXAMPLE:
Given:
• Step 1—Pollutant concentrations in
bulk sewage sludge (dry weight basis):
Pollutant
Arsenic
Cadmium
Chromium
Copper
Lead
Molybdenum
Nickel
Selenium
Zinc
Concentration
(rng*9)
10
7
850
741
134
5
9
42
5
1201
• Step 2—Assume the annual whole
sludge application rate for the bulk
sewage sludge is 10 MT/ha/365 day
period base on agronomic requirements.
• Step 3—Calculate the annual
pollutant loading rates for the pollutants
using equation (1):
Pollutant
Arsenic
Cadmium
Chromium
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc
Concentration
(mg/kg)
10
7
850
741
134
5
9
42
5
1201
APLR (kg/
ha)
010
0.07
850
7.40
1.30
0.05
0.09
042
0.05
12.00
• Step 4—Calculate the years an
inorganic pollutant can be applied to
the land:
Pollutant
Cadmium
Chromium
Copper
Lead
Mercury .
Molybdenum
Nickel
Selenium
Zinc
CPLR
(kg/ha)
41
39
3000
1500
300
17
18
420
100
2800
APLR
(kg/ha/yr)
0 10
0.07
8.5
74
1.3
005
0.09
0.42
0.05
12.0
Years
(CPLR/
APLR)
410
557
353
202
231
340
200
1000
2000
233
• Step 5—Determine the lowest
number of years calculated in Step 4:
For this example, the lowest number
of years is 200 for molybdenum. Bulk
sewage sludge with the inorganic
pollutant concentrations given in Step 1
of this procedure can be applied to the
land at an AWSAR of 10 MT/ha for 200
years. After that period, the cumulative
pollutant loading rate for molybdenum
is exceeded.
The values for the cumulative
pollutant loading rates in the final part
503 regulation are different from the
values for those rates in the proposal.
They are different because values for the
input parameters for the models used in
the exposure assessment to develop the
loading rates were updated using
information received during the public
comment period on the proposal and
other information obtained subsequent
-------
9334 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
to the proposal. This is discussed in
moro detail in the land application
technical support document.
The second pollutant limit for bulk
sewage sludge consists of pollutant
concentrations in Table 3 of section
503.13 that designate high quality
sewage sludges. These concentrations
wore called "alternative pollutant limits
(APL)" in the November 1990 National
Sewage Sludge Survey notice (55 FR
47210, November 9,1990). The Agency
chose not to call the pollutant
concentrations "alternative pollutant
limits" in the final part 503 regulation
because the other pollutant limits in the
land application subpart (i.e.,
cumulative pollutant loading rates) also
are alternative limits. Any of the
alternative pollutant limits can be met
when bulk sewage sludge is applied to
the land. The APLs in the 1990 notice
are called pollutant concentrations in
the final part 503 regulation.
To develop the pollutant
concentrations in Table 3 of section
503.13, the cumulative pollutant
loading rates for inorganic pollutants
established in the land application
exposure assessment were converted to
annual pollutant loading rates. Next, the
calculated annual pollutant loading
rates and an assumed annual whole
sludge application rate (AWSAR) were
used in the following equation to
calculate a pollutant concentration:
APLR
AWSARxO.OOl
(1)
Where:
Opollutant concentration in mg/kg (dry
weight basis).
APLR«annual pollutant loading rate in kg-
pollutant/hoctare/365 day period.
AWSAR=annual whole sludge application
rato in metric tons/hoctaro/365 day
period (dry weight basis).
0.001*a conversion factor.
Finally, the pollutant concentrations
calculated using equation (1) were
compared to the 99th percentile
concentration values for the pollutants
from the NSSS. The pollutant
concentrations in Table 3 of section
503.13 are either the concentration
calculated using equation (1) or the 99th
porcentile concentration, whichever is
more stringent. The rationale for the use
of the 90th percentile concentration is
presented in part VII of today's
preamble.
To convert the cumulative pollutant
loading rates for inorganic pollutants to
annual pollutant loading rates, the
Agency assumed that the life of the site
where the bulk sewage sludge is applied
is 100 years. Annual pollutant loading
rates were calculated by dividing the
cumulative pollutant loading rates in
Table 2 of section 503.13 by 100 years.
EPA concluded that using a site life of
100 years is conservative because bulk
sewage sludge most likely will not be
applied to a site for 100 years,
particularly 100 years in a row.
For the purpose of calculating the
pollutant concentrations using equation
(1), EPA also assumed that the AWSAR
is 10 metric tons/hectare/365 day
period. This rate is a conservative
application rate for agricultural land
based on nitrogen requirements of the
crop and the nitrogen concentration in
the sewage sludge.
Because the annual whole application
rates for other types of land differ from
the assumed rate for agricultural land,
the Agency estimated the site life for the
other types of land using the pollutants
concentrations in Table 3 of section
503.13 and the different AWSARs in
equation (1) above. An annual whole
sludge application rate of 26,18, and 74
metric tons/hectare/365 day period was
used for forest, a public contact site, and
a reclamation site, respectively. These
rates were obtained from the NSSS.
The estimated site lives for a forest, a
public contact site, and a reclamation
site calculated using the above
AWSARs, the pollutant concentration
from Table 3 of section 503.13, and the
cumulative pollutant loading rates from
Table 2 of section 503.13 (i.e.,
cumulative pollutant loading rate
divided by site life) in equation (1) are
38 years, 55 years, and 13 years,
respectively. This means that when the
pollutant concentrations in the sewage
sludge are equal to or less than the
concentrations in Table 3 of section
503.13 bulk sewage sludge can be
applied to the different types of land at
the above application for the above
years without causing any of the
cumulative pollutant loading rates in
Table 2 of section 503.13 to be
exceeded. The Agency concluded that it
is unlikely that bulk sewage sludge will
be applied to a forest for 38 years, to a
public contact for 55 years, or to a
reclamation site for 13 years. EPA also
concluded that bulk sewage sludge will
not be applied to those types of land at
substantially higher application rates
than 26,18, and 74 metric tons/per
hectare/365 day period for a forest, a
public contact site, or a reclamation site,
respectively, because of the
management practice in the land
application subpart that requires the
sewage sludge to be applied to the land
at a rate that is equal to or less than the
agronomic rate.
Another reason a 13 year site life for
a reclamation site is conservative is that
13 years are not needed to reclaim a site.
Available information indicates that, at
most, three or four years are needed to
reclaim land. This does not mean that
sewage sludge cannot be applied to the
land after three or four years. It means
that after that period, the land is no
longer a reclamation site. It becomes a
different type of land (e.g., agricultural
land). In that case, the part 503
requirements for the other type of land
have to be met when sewage sludge is
applied to the land after it is reclaimed.
EPA is applying the 99th percentile
concentration "cap" to designate high
quality sewage sludges because certain
parts of the land application subpart
(i.e., general conditions and
management practices) do not apply
when the sewage sludge meets the
pollutant concentrations and other
requirements. This is the case when the
sewage sludge meets the pollutant
concentrations in Table 3 of section
503.13, the more stringent Class A
pathogen requirements, and one of the
appropriate vector attraction
requirements.
Using the above approach, the
concentration values for three of the
pollutants in Table 3 of section 503.13
(i.e., chromium, nickel, and selenium)
are "capped" at the 99th percentile
value. Concentration values for the
other pollutants in Table 3 of section
503.13 are the values for those
pollutants calculated using equation (1).
The calculated annual pollutant
loading rates for the inorganic
pollutants based on a 100 year site life
protect public health and the
environment from reasonably
anticipated adverse effects of pollutants
in sewage sludge because they are
derived from cumulative pollutant
loading rates that provide the same
protection. Pollutant concentrations
(i.e., the values in Table 3 of section
503.13) based on the calculated annual
pollutant loading rates provide equal
protection to public health and the
environment. In the case of the
pollutant concentrations that are
"capped", public health and the
environment also are protected because
those concentrations are more stringent
than the pollutant concentrations
calculated using equation (1).
Because the pollutant concentrations
in Table 3 of section 503.13 are based
on conservative site lives and typical
AWSARs, the Agency concluded that
records do not have to be kept of the
amount of each inorganic pollutant in
the bulk sewage sludge applied to a site.
It is unlikely that any of the cumulative
pollutant loading rates in Table 2 of
section 503.13 will be exceeded at a site
when the bulk sewage sludge applied to
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9335
the site meets the pollutant
concentrations in Table 3 of section
503.13. The pollutant concentrations in
Table 3 of section 503.13 are monthly
average concentrations. The monthly
average concentration of the pollutant in
the sewage sludge that is applied to the
land cannot exceed the value for the
pollutant in Table 3 of section 503.13.
The Agency considered allowing site-
specific cumulative pollutant loading
rates to be developed for land
application of bulk sewage sludge but
decided not to allow that type of
pollutant limit for several reasons. First,
to develop site-specific cumulative
pollutant loading rates, a site-specific
exposure assessment has to be
conducted. For many of the pathways in
the exposure assessment, the terms in
the algorithm used to calculate the
allowable loading rate are based on
policy decisions (e.g., the RfD for a
pollutant and the soil ingestion rate).
EPA does not believe that values for
those terms should be changed in a site-
specific assessment. For this reason,
when the limiting cumulative pollutant
loading rate for a pollutant is based on
a pathway for which the algorithm only
contains terms based on a policy
decision, a site-specific cumulative
pollutant loading rate could not be
calculated for that pollutant. This is the
case for four of the 10 inorganic
pollutants for which cumulative
pollutant loading rates are included in
the land application subpart.
Another reason is the information that
must be developed to conduct a site-
specific pathway risk assessment. This
includes, among other things, pollutant
uptake slopes for each crop grown on
each site, information on the uptake of
a pollutant by a grazing animal for each
application site, and variables for the
ground-water pathway (e.g., depth to
ground water) for each application site.
Much of this information is difficult and
expensive to obtain, particularly for
every land application site.
A third reason the Agency decided
not to allow site-specific cumulative
pollutant loading rates is that site-
specific cumulative pollutant loading
rates have to be developed for each land
application site. A person who prepares
sewage sludge does not just develop one
set of site-specific cumulative pollutant
loading rates and use those rates for all
application sites. Instead, a different
site-specific cumulative pollutant
loading rate has to be developed for
each site. Considering the information
that has to be developed to conduct site-
specific exposure assessment and the
cost to obtain that information, the
Agency concluded that it is not feasible
to conduct such an assessment for each
application site.
The final part 503 regulation also
contains two pollutant limits for sewage
sludge sold or given away in a bag or
other container for application to the
land. The first group is the pollutant
concentrations designating high quality
sewage sludge in Table 3 of section
503.13. If the concentration of any
pollutant listed in Table 3 of section
503.13 in the sewage sludge sold or
given away in a bag or other container
for application to the land exceeds the
concentration for the pollutant in Table
3 of section 503.13, the annual pollutant
loading rates have to be met.
The annual pollutant loading rates for
sewage sludge sold or given away in a
bag or other container are presented in
Table 4 of section 503.13. The final rule
requires that the product of the
concentration for each pollutant listed
in Table 4 of section 503.13 in sewage
sludge sold or given away in a bag or
other container for application to the
land and the annual whole sludge
application rate for the sewage sludge
not cause the annual pollutant loading
rate for the pollutant in Table 4 of
section 503.13 to be exceeded. The
procedure used to determine the annual
whole sludge application rate for a
sewage sludge that does not cause any
of the annual pollutant loading rates in
Table 4 to be exceeded is presented in
appendix A of the final part 503
regulation.
The person who prepares sewage
sludge that is sold or given away in a
bag or other container has to determine
the rate at which the sewage sludge may
be applied to the land and not violate
any of the cumulative pollutant loading
rates in Table 2 of section 503.13. EPA
has simplified that decision by
calculating an annual pollutant loading
rate for each pollutant using
conservative assumptions, as discussed
below. Using the procedure in appendix
A, the person who prepares the sewage
sludge calculates the rate that does not
cause any of the annual pollutant
loading rates in Table 4 of section
503.13 to be exceeded and places that
rate on a label or information sheet.
The annual pollutant loading rates in
Table 4 of section 503.13 were
calculated using the cumulative
pollutant loading rates in Table 2 of
section 503.13 and an assumed site life
of 20 years for the land where the
sewage sludge is applied. The Agency
concluded that 20 years is a
conservative assumption because most
likely sewage sludge sold or given away
in a bag or other container will be
applied to a lawn, a home garden, or a
public contact site. EPA does not
believe sewage sludge will be applied to
those types of land for longer than 20
years, particularly 20 years in a row.
The annual pollutant loading rates in
Table 4 of section 503.13 protect public
health and the environment from the
reasonably anticipated adverse effect of
the pollutants in sewage sludge because
they are calculated using the cumulative
pollutant loading rates in Table 2 of
section 503.13. The cumulative
pollutant loading rates in Table 2 of
section 503.13 are based on the results
of the land application exposure
assessment.
The final part 503 regulation contains
a separate pollutant limit for domestic
septage applied to agricultural land,
forest, or a reclamation site. This
requirement is an annual application
rate.
The annual application rate for
domestic septage is related to the
amount of nitrogen needed by the crop
grown on the application site by the
following equation:
N=ANCxAARx8.34
(2)
Where:
N=pounds of nitrogen needed by the crop
per acre per 365 day period.
ANC=available nitrogen concentration in
milligrams per liter.
AAR=annual application rate in million
gallons per acre per year.
8.34=a conversion factor.
Rearranging equation (2) to solve for
the annual application rate results in the
following equation:
AAR=
N
ANCxS.34
(3)
The part 503 regulation requires that
the allowable annual application rate for
a site be calculated using the following
equation, which is equation (3) with a
value substituted for ANCx8.34:
AAR=
N
0.0026
(4)
The amount of nitrogen, N, needed
depends on the crop grown on the land.
Values for the amount of nitrogen
needed by crops may be obtained from
various sources (e.g., Agricultural
Extension Services). Once the value for
the crop grown on the land is known,
that value is divided by 0.0026 to obtain
the allowable annual application for a
particular site. The amount of nitrogen
needed could vary from year-to-year
depending on the type of crop grown on
the land.
As mentioned above, 0.0026 in
equation (4) is die product of an
-------
9336 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
available nitrogen concentration and a
conversion factor (i.e., 8.34/1,000,000).
This concentration was calculated using
values for Total Kjeldahl Nitrogen
(TKN) and ammonia-N in domestic
saptogo obtained from the results of the
analysis of nine samples of domestic
soptage collected in Madison,
Wisconsin. In addition, the following
assumptions were made to calculate the
available nitrogen concentrations:
• Domestic septage is applied to a site
overyyear.
• The domestic septage is injected
bolow the land surface.
• None of the ammonia-N in the
domestic septage is lost through
volatilization.
* Most of the organic nitrogen (i.e.,
TKN—ammonia) in the domestic
septage becomes available over a three
year period. Fifty percent is available
the year domestic septage is applied to
the land, 20 percent is available in the
second year, and 10 percent is available
In the third. The remaining organic-N,
which was assumed to become available
at three percent per year until no more
organic-N remains, was not considered
in the calculation of the available
nitrogen concentration.
• Steady state" conditions are
achieved with respect to the available
nitrogen concentration in the third year
after application of the domestic
soptngo.
Details for the calculation of the
available nitrogen concentration used to
calculate the 0.0026 value in equation
(4) and the justification that the annual
application rate for domestic septage
protects public health and the
environment from the reasonably
anticipated adverse effects of pollutants
in domestic septage are presented in the
technical support document for the part
503 land application requirements.
EPA chose to limit the annual
application rate to domestic septage for
two reasons. First, available data
indicate that domestic septage has
pollutant concentrations that are lower
than the pollutant concentrations in
commercial/industrial septage (e.g.,
grease from grease traps). Second, the
concentrations in commercial/industrial
septago vary greatly. The higher
pollutant concentrations and the
variability of those concentrations
requires that samples of commercial/
industrial septage be analyzed
periodically to determine the quality of
the commercial/industrial septage prior
to use or disposal. For these reasons, the
annual application rate limit for
domestic septage is not appropriate for
commercial/industrial septage.
EPA also chose to allow the annual
application rate to be used only when
domestic septage is applied to
agricultural land, forest, or a
reclamation site because certain site
restrictions are imposed on the site
where the domestic septage is applied.
EPA's determination is based on the
assumption that the applier has control
over the application site. Because of the
difficulty of imposing site restrictions
on a public contact site, a lawn, or a
home garden, the Agency is prohibiting
the application of domestic septage to a
public contact site, a lawn, or a home
garden at an annual application rate.
Management Practices (Section 503.14)
Two of the management practices for
land application of bulk sewage sludge
in the proposed part 503 regulation
were deleted from the final part 503
regulation. One of those management
practices concerned the limit on the
annual amount of bulk sewage sludge
that can be applied (i.e., 50 metric tons
per hectare). The 50 metric ton per
hectare restriction was included in the
proposal because the exposure
assessment models used to develop the
annual pollutant loading rates could not
be used for an annual whole sludge
application rate greater than 50 metric
tons per hectare. Subsequent to the
proposal, the models were changed so
that application rates greater than 50
metric tons per hectare can be used and
protection of public health and the
environment is still ensured. For this
reason, the 50 metric ton per hectare
restriction is no longer needed.
The second management practice no
longer found in the land application
subpart of the final part 503 regulation
concerns crop and access restrictions for
pathogen reduction. Those restrictions
are now included in subpart D of the
final part 503 regulation, which
addresses both pathogen and vector
attraction reduction.
The following management practices
are included in the final part 503
regulation and apply when bulk sewage
sludge is applied to agricultural land,
forest, a public contact site, or a
reclamation site. These management
practices do not apply when bulk
sewage sludge is applied to a lawn or a
home garden because EPA determined
that large amounts of bulk sewage
sludge will not be applied to a lawn or
a home garden for several applications.
For this reason, the Agency concluded
the management practices are not
needed to protect public health and the
environment when bulk sewage sludge
is applied to a lawn or a home garden.
Moreover, the pollutant limits already
ensure a high degree of protection.
Further, the management practices in
many cases have no relevance in a lawn
or home garden setting. The following
discussion explains the management
practices EPA requires when bulk
sewage sludge is applied to other than
lawns or home gardens.
Part 503 requires that application of
sewage sludge to the land is prohibited
if it is likely to adversely affect a
threatened or endangered species listed
under section 4 of the Endangered
Species Act or its designated critical
habitat (§ 503.14(a)). EPA will develop
guidance to carry out this provision
consistent with the Endangered Species
Act.
Bulk sewage sludge cannot be applied
to agricultural land, forest, a public
contact site, or a reclamation site that is
flooded, frozen, or snow-covered so that
the bulk sewage sludge enters a wetland
or other waters of the United States,
except as provided in a permit issued
pursuant to section 402 or section 404
of the Clean Water Act, as amended.
This provision codifies the prohibition
in section 405 (a) that prohibits disposal
of sewage sludge that results in
pollutants in the sewage sludge entering
navigable waters. This management
practice does not prohibit the
application of bulk sewage sludge to
flooded, frozen, or snow-covered land in
all cases. It only prohibits application of
bulk sewage sludge to flooded, frozen,
or snow-covered land when the bulk
sewage sludge enters a wetland or other
waters of the United States, except as
provided in a section 402 or section 404
permit. EPA did not calculate pollutant
limits in this subpart that protect waters
of the United States from runoff from
flooded, frozen, or snow-covered land
on which bulk sewage sludge is applied.
The Agency's assessment did not model
that scenario. Instead, that protection is
provided through this management
practice.
Section 301 of the CWA includes a
prohibition against the discharge of
pollutants into wetlands or other waters
of the United States, unless in
compliance with relevant provisions of
the CWA. As mentioned above, section
405 (a) of the CWA specifically prohibits
discharge of pollutants in sewage sludge
into navigable water, except in
compliance with a permit issued under
section 402. Most point source
discharges of dredged or fill material
into waters of the United States must be
authorized by a permit issued by the
U.S. Army Corps of Engineers (COE)
under section 404. Other point source
discharges of pollutants into waters of
the United States must be authorized by
a permit issued by EPA or a delegated
State under section 402_.
At times, it may be difficult to
determine whether a particular
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9337
pollutant constitutes "fill" material
subject to section 404 or a waste product
more appropriately regulated under
section 402. To provide guidance on
this issue, EPA and the COE signed a
Memorandum of Agreement Concerning
Regulation of Discharges of Solid Waste
Under the Clean Water Act (MOA) in
1986 (51 FR 8871, March 14,1986). For
additional guidance on this issue,
contact the appropriate EPA Regional
wetlands representative.
Another management practice in the
land application subpart requires that
bulk sewage sludge be applied to the
agricultural land, forest, or a public
contact site at a rate that does not
exceed an agronomic rate. This
requirement also applies to a
reclamation site, unless the permitting
authority authorizes larger amounts of
bulk sewage sludge to be applied to a
reclamation site.
An agronomic rate is the whole sludge
application rate for a bulk sewage
sludge designed: (1) To provide the
amount of nitrogen needed by the crop
or vegetation grown on the land and (2)
to minimize the amount of nitrogen in
the bulk sewage sludge that passes
below the root zone for the crop or
vegetation grown on the land to the
ground water. The key to the definition
is the design of the whole sludge
application rate.
Several factors must be considered to
design an agronomic rate for a land
application site. These include, but are
not limited to, the amount of nitrogen
needed by the crop or vegetation grown
on the land; the amount of organic
nitrogen from previous applications of
nitrogen-containing materials that
becomes available each year; the type of
soil at the site; and the geologic
conditions of the site. As previously
mentioned, the regulation includes a
general requirement that requires
information needed to determine the
agronomic rate be provided to the
appropriate person.
Note that the agronomic rate is
designed to minimize the amount of
nitrogen that passes below the root zone
of the crop or vegetation grown on the
land to the ground water. This
recognizes that some of the nitrogen in
the bulk sewage sludge may reach the
ground water. However, the Agency
concluded that by designing the rate to
minimize that amount, long-term
contamination of the ground water is
not reasonably likely to occur because
substantially all of the nitrogen is taken
up by the crop or vegetation grown on
the land.
The final part 503 regulation also
contains one management practice for
sewage sludge sold or given away in a
bag or other container for application to
the land. This management practice
requires labelling of the bag or other
container in which the sewage sludge is
sold or given away or that an
information sheet be provided to the
person who receives the sewage sludge
that is sold or given away in another
container. The label or information
sheet must contain the name and
address of the person who prepares the
sewage sludge that is sold or given
away, a statement that prohibits
application of the sewage sludge to the
land except in accordance with the
instructions on the label or information
sheet, and the application rate for the
sewage sludge. The requirements for the
label or information sheet are minimum
requirements. The person who prepares
sewage sludge that is sold or given away
in a bag or other container may include
additional information on the label or
information sheet (e.g., information
required by a state or local government).
Operational Standard—Pathogens and
Vector Attraction Reduction (Section
503.15)
This section indicates the class of
pathogen reduction a sewage sludge
must meet when applied to a certain
type of land, the pathogen requirements
that must be met when domestic septage
is applied to agricultural land, a forest,
or a reclamation site, and the alternative
vector attraction reduction requirements
that can be met when sewage sludge is
applied to the land. The description of
the different pathogen and vector
attraction reduction requirements is
presented in subpart D of the final part
503 regulation.
The final part 503 regulation requires
that bulk sewage sludge applied to
agricultural land, forest, a public contact
site, or a reclamation site meet either the
Class A pathogen requirements or the
Class B pathogen requirements. When
the sewage sludge is Class B with
respect to pathogens, restrictions (e.g.,
growing of root crops) are imposed on
the site where the sewage sludge is
applied. Under this approach, the
sewage sludge can be treated to reduce
pathogens (Class A) or a combination of
treatment and environmental
attenuation (i.e. Class B with site
restrictions) can be used to reduce
pathogens. In the judgment of the
Administrator of EPA, in either case
public health and the environment are
protected against the reasonably
anticipated adverse effects of pathogens
in sewage sludge that is applied to the
land.
Bulk sewage sludge applied to a lawn
or a home garden must meet the Class
A pathogen requirements. The reason
for this requirement is that it is not
feasible to impose site restrictions on a
lawn or a home garden on which bulk
sewage sludge is applied. In lieu of
having to impose site restrictions, which
would be needed if the bulk sewage
sludge only meets the Class B pathogen
requirements, the bulk sewage sludge
has to meet the Class A pathogen
requirements. Sewage sludge sold or
given away in a bag or other container
for application also must meet the Class
A pathogen requirements for the same
reasons.
When domestic septage is applied to
agricultural land, forest, or a
reclamation site, either site restrictions
(i.e., the same site restrictions that must
be met when a Class B sewage sludge is
applied to the land) must be met or a pH
requirement for the domestic septage
has to be met along with site restrictions
concerning the harvesting of crops. The
first requirement relies on the
environment to reduce pathogens
during the time that certain activities on
the site are restricted. These restrictions
prohibit harvesting of crops, grazing of
animals, and public access to the site for
a certain period. The second
requirement relies on treatment of the
domestic septage (i.e., pH adjustment)
and restrictions on harvesting crops to
reduce pathogens. Restrictions on
harvesting of crops are part of the
second requirement because the Agency
does not believe adequate pathogen
reduction is achieved by pH adjustment
to allow crops to be harvested
immediately after applying the domestic
septage. These provisions are consistent
with the provisions currently in 40 CFR
part 257 (Criteria for Classification of
Solid Waste Disposal Facilities and
Practices) for septic tank pumpings
applied to the land.
One of 10 vector attraction reduction
requirements also must be met when
bulk sewage sludge is applied to the
agricultural land, forest, a public contact
site, or a reclamation site. These
requirements are designed to reduce the
characteristics of the sewage sludge that
attract vectors such as rats, mosquitos,
and flies. In the judgment of the EPA,
any of the 10 alternative vector
attraction requirements protect public
health and the environment from the
reasonably anticipated adverse effects of
the characteristics in sewage sludge that
attract vectors. Note that the vector
attraction requirement is in addition to
the pathogen requirement discussed
above. Both requirements must be met.
One of the first eight vector attraction
reduction requirements for bulk sewage
sludge applied to agricultural land,
forest, a public contact site, or a
reclamation site must be met when bulk
-------
9338 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sowngo sludge is applied to a lawn or a
home garden. Injection of sewage sludge
bolow the land surface and
incorporation sewage sludge into the
soil cannot be used to achieve vector
attraction reduction in these cases.
Implementation of these requirements
for bulk sewage sludge applied to a
lawn or a home garden would be
difficult, if not impossible. For this
reason, those alternative are not
available for achieving vector attraction
reduction when bulk sewage sludge
applied to a lawn or a home garden.
One of the first eight vector attraction
reduction requirements for bulk sewage
sludge applied to agricultural land,
forest, a public contact site, or a
reclamation site also must be met when
sewage sludge is sold or given away in
a bag or other container for application
to the land. Again, in this situation it is
not feasible to inject the sewage sludge
bolow the land surface or to incorporate
the sewage sludge into the soil.
Vector attraction reduction is
achieved when domestic septage is
applied to agricultural land, forest, or a
reclamation site when the domestic
septage is injected below the surface of
the land, incorporated into the soil after
being applied to the land surface, or the
pH of the domestic septage is raised to
12 or higher and remains at 12 or higher
for 30 minutes. When vector attraction
reduction is achieved by raising the pH
of the domestic septage, each container
(e.g., each tank truck Toad) of domestic
soptago that is applied to the land must
bo monitored to demonstrate
compliance with that requirement.
Again, those provisions are consistent
with those for septic tank pumpings in
40 CFR part 257.
Frequency of Monitoring (Section
503.16)
The final part 503 regulation contains
the frequency of monitoring
requirements for pollutant
concentrations in sewage sludge and for
compliance with the pathogen density
and certain vector attraction reduction
requirements. Frequency of monitoring
requirements, which also are included
in the subparts on surface disposal and
incineration, are needed to make the
part 503 regulation self-implementing.
The frequency of monitoring
requirements in this subpart for
pollutant concentrations, pathogen
density requirements, and vector
attraction reduction requirements vary
with the amount of bulk sewage sludge
used or disposed annually. In the case
of sewage sludge sold or given away in
a bag or other container for application
to the land, the frequency of monitoring
requirements are based on the amount
of sewage sludge received by the person
who prepares the sewage sludge that is
sold or given away in a bag or other
container.
The amount of sewage sludge used or
disposed was chosen as the unit of
measurement on which the frequency of
monitoring is based because the
requirements in the final part 503
regulation apply to sewage sludge that
is used or disposed. The amounts in the
frequency table are based on dry weight
because all of the pollutant limits in the
final part 503 regulation are on a dry
weight basis.
Before the derivation of the
frequencies of monitoring is discussed,
one other aspect of the frequencies
needs to be addressed. This concerns
the lowest range for the frequencies of
monitoring (i.e., greater than zero but
less than 290 metric tons per 365-day
period). This range indicates that when
sewage sludge is not used or disposed
during a 365-day period, the sewage
sludge does not have to be monitored
for the requirements in the part 503
regulation. The sewage sludge must be
monitored only when an amount is used
or disposed.
The amount of sewage sludge used or
disposed in the frequency of monitoring
requirements is related to the flow rate
for the treatment works. For example,
the range of "greater than 290 metric
tons per 365-day period to equal to or
less than 1,500 metric tons per 365-day
period" corresponds to a wastewater
flow rate range of "greater than one
MGD to equal to or less than five MGD".
The Agency made various assumptions
concerning the influent and effluent
five-day biochemical oxygen demand
and total suspended solids wastewater
concentrations; the percent removal for
total suspended solids in the primary
clarifier; the percent removal of five-day
biochemical oxygen demand through
secondary treatment; the percent fixed
solids in the sewage sludge in the
influent to the stabilization process; and
the percent volatile solids removed in
the sewage sludge stabilization process
to calculate the amount of sewage
sludge used or disposed. Details of these
calculations are presented in the
technical support document for the part
503 land applic
splication requirements.
The final part 503 regulation allows
the permitting authority to reduce the
frequency of monitoring for pollutant
concentrations and the pathogen density
requirements for enteric viruses and
viable helminth ova in 503.32(a)(5)(ii)
and 503.32(a)(5)(iii), respectively, after
monitoring for two years at the
frequency in the final part 503
regulation. However, in no case should
the frequency of monitoring be less than
once per year when sewage sludge is
applied to the land. Requiring the
sewage sludge to be monitored at least
once per year when sewage sludge is
applied to the land is consistent with
the frequency of monitoring
requirement in EPA's state sludge
management program requirement
regulation (i.e., 40 CFR 501.15(b)(10)).
In deciding whether to reduce the
frequency of monitoring, the permitting
authority should consider the variability
of the pollutant concentrations, the
magnitude of the pollutant
concentrations, and the frequency of
detection of enteric viruses and viable
helminth ova in the sewage sludge. The
Agency concluded that data collected
over a two-year are adequate to calculate
the variability of pollutant
concentrations and to determine the
magnitude of the pollutant
concentrations before deciding whether
to change the frequency of monitoring.
As mentioned above, the frequency of
monitoring for the pathogen density
requirements in 503.32(a)(5)(ii) and
503.32(a)(5)(iii) may be reduced. These
requirements address enteric viruses
and viable helminth ova, respectively,
in sewage sludge. As part of those
requirements, the sewage sludge must
be analyzed for enteric viruses and
viable helminth ova every time the
sewage sludge is monitored. After those
two organisms are found in the influent
to the pathogen treatment process and
after the required reduction for those
organisms is demonstrated through the
pathogen treatment process, the sewage
sludge does not have to be monitored
for enteric viruses and viable helminth
ova when values for the process
operating parameters are consistent with
the documented values for those
parameters. Because the costs and
complexity of the analytical methods for
enteric viruses and viable helminth ova,
the Agency decided to allow the
permitting authority to judge whether to
reduce the frequency of monitoring after
monitoring at the frequency in the final
part 503 regulation for two years. The
Agency concluded that two years of
monitoring should provide enough
information to make that judgment.
Note that the potential reduction in
frequency of monitoring applies only to
the pathogen density reduction
requirements for enteric viruses and
viable helminth ova mentioned above.
The frequency of monitoring cannot be
reduced for the other pathogen density
requirements.
The final part 503 regulation requires
that every container of domestic septage
applied to agricultural land, forest, or a
reclamation site be monitored to
determine compliance with the pH
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9339
adjustment requirement when that
requirement is met. Every container
(e.g., each tank truck load applied to the
land) must be monitored because there
is no way to ensure that the domestic
septage in each container meets the pH
requirement by monitoring domestic
septage in only a certain number of
containers.
Recordkeeping (Section 503.17)
The final part 503 regulation contains
recordkeeping requirements for: (1) Bulk
sewage sludge that meets the pollutant
concentrations for high quality sewage
sludge in 503.13(b)(3), the more
stringent Class A pathogen requirements
in 503.32(a), and one of vector attraction
reduction requirements in 503.33(b)(l)
through 503.33(b)(8); a bulk material
derived from sewage sludge that meets
those three requirements; and sewage
sludge sold or given away in a bag or
other container for application to the
land that meets those three
requirements; (2) bulk sewage sludge
applied to the land that does not meet
the above requirements; (3) sewage
sludge sold or given away in a bag or
other container for application to the
land that does not meet the above
requirements; and (4) domestic septage
applied to agricultural land, forest, or a
reclamation site. Recordkeeping
requirements are included in the final
regulation to make the regulation self-
implementing.
The recordkeeping requirements for
bulk sewage sludge and sewage sludge
sold or given away in a bag or other
container for application to the land
specify the information that must be
developed, the person who must
develop and retain the information, and
the period that the information must be
retained. The information that must be
developed varies depending on which
pollutant limits are met and on which
pathogen and vector attraction
reduction requirements are met. This
information is needed to show that the
requirements in this subpart are met.
The recordkeeping requirements for
domestic septage applied to agricultural
land, forest, or a reclamation site also
specify the information that must be
developed, the person who develops
and retains the information, and the
period the information has to be
retained. This information indicates
whether the requirements in this
subpart for domestic septage are met.
The person who develops and retains
the information for bulk sewage sludge
that meets the pollutant concentrations
for high quality sewage sludges in
503.13(b)(3), the more stringent Class A
pathogen requirements in 503.32(a), and
one of the vector attraction requirements
in 503.33(b)(l) through 503.33(b)(8); a
material derived from bulk sewage
sludge that meets those requirements; or
sewage sludge sold or given away in a
bag or other container that meets those
requirements is the person who
prepares the sewage sludge. That person
may be the treatment works or some
other person.
The persons who develop and keep
the information for bulk sewage sludge
that does not meet the above
requirements and is applied to
agricultural land, forest, a public contact
site, a reclamation site, a lawn, or a
home garden are the person who
prepares the bulk sewage sludge and the
person who applies the bulk sewage
sludge to the land. The person who
prepares the bulk sewage sludge must
develop certain information (e.g.,
pollutant concentrations in the sewage
sludge) and the applier must develop
other information (e.g., the record of the
amount of each pollutant applied to the
land). Those persons may be the
treatment works, an agent of the
treatment works, a private contractor, or
some other person.
An example of when the person who
prepares the bulk sewage sludge does
not develop and keep the information is
when the bulk sewage sludge meets the
pollutant concentrations for high quality
sewage sludge in 503.13(b)(3) and the
less stringent Class B pathogen
requirements. In those situations, the
person who applies the bulk sewage
sludge to the land must develop
information concerning certain part 503
requirements (e.g., the restrictions on
the application site). The Agency
concluded that the person who applies
the bulk sewage sludge to the land is the
appropriate person to develop that
information and keep the records.
For sewage sludge sold or given away
in a bag or other container for
application to the land, the
recordkeeping responsibility lies with
the person who prepares the sewage
sludge that is sold or given away in a
bag or other container for application to
the land. For domestic septage applied
to agricultural land, forest, or a
reclamation site, the responsible person
is the one who applies the domestic
septage to those types of land.
The period that information must be
retained varies depending on which
pollutant limits are met. hi most cases
(including the requirements for
domestic septage), the time is five years
(i.e., the usual period for a NPDES
permit). However, when cumulative
pollutant loading rates are met, records
for certain information have to be
retained indefinitely. The reason for this
requirement is that a cumulative
pollutant loading rate is the cumulative
amount of an inorganic pollutant that
can be applied to the land. To know
how much of an inorganic pollutant has
been applied to the land in bulk sewage
sludge, a record must be retained
indefinitely.
Reporting (Section 503.18)
The final part 503 regulation requires
that Class I sludge management
facilities, POTWs with a design flow
rate equal to or greater than one million
gallons per day, and POTWs that serve
10,000 people or more to report the
information developed in the
recordkeeping section, except the
information developed and retained by
an applier, to the permitting authority
once every 365 day period. Class I
sludge management facilities, POTWs
with a design flow rate equal to or
greater than one million gallons, and
POTWs that serve 10,000 people or
more must report the information on
cumulative pollutant loading rates,
which is developed and retained by the
applier, when 90 percent or more of any
of the cumulative pollutant loading
rates are reached at a site. The Agency
chose only to require Class I sludge
management facilities, POTWs with a
design flow rate equal to or greater than
one million gallons per day, and POTWs
that serve 10,000 people or more to
report information to the permitting
authority. This was done because Class
I sludge management facilities are either
a publicly owned treatment works
(POTW) required to have a pretreatment
program or a treatment works treating
domestic sewage (TWTDS) that has the
potential to affect public health and the
environment adversely because of the
TWTDS's sewage sludge use or disposal
practice.
Pretreatment POTWs are POTWs that
receive industrial wastewater and, thus,
are more likely to generate sewage
sludge that contains the pollutants
controlled in the final part 503
regulation. For this reason, the Agency
concluded that those POTWs should
report the information on sewage sludge
use or disposal to the permitting
authority at least once every 365 days.
The reporting requirement also applies
to TWTDS for the same reason they are
classified as a Class I facility (i.e. the
potential of the TWTDS's sewage sludge
use or disposal practice to affect public
health and the environment adversely).
The reporting requirement applies to
POTW's that are not a Class I facility
and either have a design flow rate equal
to or greater than one million gallons
per day or serve 10,000 people or more
because of the potential for those
POTWs to have industrial wastewater in
-------
9340 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
the influent to the POTW. Sewage
sludge generated at those FOTW's is
moro likely to have the pollutants
controlled in the part 503 regulation.
For tills reason, the Agency concluded
those FOTVVs also should report the
information in the recordkeeping
section to the permitting authority.
Surface Disposal (Subpart C)
This part of today's preamble
discusses the part 503 requirements for
surface disposal of sewage sludge. More
details on these requirements can be
found in the technical support
document for the part 503 surface
disposal requirements.
Applicability (Section 503.20)
The applicability section indicates
that this subpart contains requirements
for a person who prepares sewage
sludge that is placed on a surface
disposal site, the owner/operator of the
surface disposal site, sewage sludge
placed on a surface disposal site, and a
surface disposal site. Sewage sludge is
Elaced on an active sewage sludge unit
>r final disposal, not for treatment,
storage, or to condition the soil or
fertilize crops grown in the soil.
This subpart does not apply to sewage
sludge stored or treated on the land or
to the land on which the sewage sludge
is stored or treated. As indicated above,
sewage sludge is placed on an active
sowage sludge unit for final disposal,
not for storage or treatment.
This subpart also does not apply to
sewage sludge that remains on the land
for longer than two years when the
person who prepares the sewage sludge
demonstrates that the land on which the
sowago sludge remains is not an active
sowage sludge unit. The demonstration
must explain why sewage sludge needs
to remain on the land for longer than
two years prior to final disposal and
must discuss the approximate period
the sewage sludge will be used or
disposed. In addition, the person who
prepares the sewage sludge must retain
the information required for the
demonstration for the period that the
sowago sludge remains on the land.
Note that the person who prepares the
sewage sludge does not have to report
tho information in the demonstration
unless requested to do so by the
permitting authority.
The purpose of allowing sewage
sludge to remain on the land for a
period longer than two years and not
having to moot the requirements in this
subpart apply is to address unique
situations. In such a situation,
mitigating factors may justify the longer
period. Without mitigating factors, EPA
concluded that a two year period
provides enough time to store sewage
sludge for most purposes prior to final
use or disposal.
Special Definitions (Section 503.21)
Definitions for the following terms are
included in this subpart of the final part
503 regulation: Active sewage sludge
unit, aquifer, contaminate an aquifer,
cover, displacement, fault, final cover,
holocene time, leachate collection
system, liner, lower explosive limit for
methane gas, qualified ground water
scientist, seismic impact zone, sewage
sludge unit, sewage sludge unit
boundary, surface disposal site, and
unstable area. The following discussions
provide additional information on some
of these definitions.
Active sewage sludge unit. An active
sewage sludge unit is a sewage sludge
unit that is not closed. This definition
is included in the final part 503
regulation because requirements in the
regulation differ for a sewage sludge
unit that is active and a sewage sludge
unit that is closed. To distinguish
between the two sewage sludge units,
the term active sewage sludge unit is
used.
Aquifer. An aquifer is a geologic
formation, a group of geologic
formations, or a portion of a geologic
formation capable of yielding ground
water to wells or springs. This
definition parallels the definition found
in the current regulation controlling
disposal of sewage sludge on the land in
40 CFR part 257. It is included in the
final part 503 regulation because of the
requirement in the regulation not to
contaminate an aquifer.
Contaminate an aquifer. Contaminate
an aquifer means to introduce a
substance that causes the maximum
contaminant level (MCL) for nitrate in
40 CFR 141.11 to be exceeded in ground
water or that causes the existing
concentration of nitrate in ground water
to increase when the existing
concentration of nitrate in the ground
water already exceeds the maximum
contaminant level for nitrate in 40 CFR
141.11. This definition is included in
the final part 503 regulation because the
regulation requires that sewage sludge
placed on an active sewage sludge unit
shall not contaminate an aquifer. Note
that this requirement only applies to
nitrate. The limits for the pollutant
controlled in the surface disposal
subpart in part 503 are designed not to
cause the maximum contaminant level
for the pollutants to be exceeded in the
ground water. For this reason,
monitoring of the ground water for these
pollutants is not necessary.
Cover. Cover is soil or other material
used to cover sewage sludge placed on
an active sewage sludge unit. The
purpose of the cover is to reduce the
attraction of vectors to the sewage
sludge after the sewage sludge is placed
on the surface disposal site.
Holocene time: Holocene time is the
most recent epoch of the Quaternary
period, extending from the end of the
Pleistocene epoch to the present. The
most recent epoch of the Quaternary
period covers approximately the last
11,000 years.
Leachate collection system. A leachate
collection system is a system or device
installed immediately above a liner that
is designed, constructed, maintained,
and operated to collect and remove
leachate from a sewage sludge unit. This
definition assumes that a sewage sludge
unit has a liner. It is included in the
final part 503 regulation because the
regulation contains a management
practice that requires the leachate to be
collected and disposed in accordance
with the applicable requirements when
the sewage sludge unit has a liner and
leachate collection system.
Liner. A liner is soil or synthetic
material that has a hydraulic
conductivity of 1x10 ~7 centimeters per
second or less. The liner retards the
downward movement of liquid by
limiting the rate at which the liquid
moves to 1x10~7 centimeters per second
or less.
Lower explosive limit for methane gas.
The lower explosive limit for methane
gas is the lowest percentage of methane
gas and air, by volume, that propagates
a flame at 25 degrees Celsius and
atmospheric pressure. This definition is
included in the final part 503 regulation
because of the requirement for air in any
structures within a surface disposal site
and air at the property line of the
surface disposal site not to exceed a
percentage of the lower explosive limit
or the lower explosive limit,
respectively.
Qualified groundwater scientist. A
qualified groundwater scientist is an
individual qualified to make sound
professional judgments regarding
groundwater monitoring, pollutant fate
and transport, and corrective action.
This definition is included in the final
part 503 regulation because if a
certification is provided to demonstrate
an aquifer is not contaminated, the
certification must be made by a
qualified groundwater scientist.
Sewage sludge unit. A sewage sludge
unit is land on which only sewage
sludge is placed for final disposal. Land
does not include waters of the United
States, as defined in 40 CFR 122.2.
When sewage sludge is placed on the
land for either treatment or storage, the
land is not a sewage sludge unit.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9341
A sewage sludge unit does not
include land where sewage sludge is
applied to condition the soil or to
fertilize crops or vegetation grown on
the land. Using sewage sludge for these
purposes is land application. In those
cases, the requirements in subpart B
(Land Application) must be met.
Sewage sludge unit boundary. The
sewage sludge unit boundary is the
outermost perimeter of the sewage
sludge unit. This is different from the
property line of the surface disposal
site. This definition is needed because
part 503 requires that the distance from
the sewage sludge unit boundary to the
surface disposal site property line be
known.
Surface disposal site. A surface
disposal site is a discrete area of land
that contains one or more active sewage
sludge units. This definition is needed
because some of the requirements in
this subpart apply to a surface disposal
site. Other requirements in this subpart
apply to active sewage sludge units in
a surface disposal site.
Unstable area. An unstable area is
area of land subject to natural or human-
induced forces that may damage the
structural components of an active
sewage unit. An example of an unstable
area is an area subject to earthquakes.
General Bequirements (Section 503.22)
Several of the general requirements in
this subpart proposed for the part 503
regulation were deleted from the final
rule. They are discussed below.
The proposed regulation contained a
requirement that a surface disposal site
comply with National Pollutant
Discharge Elimination System (NPDES)
permit requirements in addition to the
requirements in this subpart. The part
503 regulation does not apply to
activities subject to a NPDES permit at
a surface disposal site other than those
that relate to the placement of sewage
sludge on an active sewage sludge unit.
For this reason, the proposed general
requirement concerning compliance
with other NPDES requirements was
deleted from the final regulation. EPA
notes, however, that section 405(a)
prohibits the disposal of sewage sludge
when it results in pollutants from the
sewage sludge entering navigable
waters, except in compliance with an
NPDES permit.
The general requirement in the
proposed regulation concerning a
hazard to human health, wildlife, land,
or water resources because of sewage
sludge in the runoff from a base flood
was deleted from the final part 503
regulation. The Agency concluded that
the management practice in this subpart
of the final part 503 regulation that
requires the runoff from an active
sewage sludge unit for a 24-hour, 25-
year storm event be collected and
disposed in accordance with the
applicable requirements protects surface
waters adequately. Similarly, as noted
above, section 405(a) already prohibits
the discharge of pollutants to navigable
waters, except under certain
circumstances.
The general requirement in this
subpart of the proposal concerning a
hazard to aircraft from birds was deleted
from the final regulation. That general
requirement was included in the
proposal because of the vector attraction
potential of sewage sludge placed on an
active sewage sludge unit. The final
regulation contains a requirement to
reduce the vector attraction of sewage
sludge before the sewage sludge is
placed on an active sewage sludge unit
or to cover the sewage sludge unit daily
to reduce vector attraction. For this
reason, this general requirement is no
longer needed.
The general requirement in the
proposed regulation concerning
reduction of the temporary water storage
capacity of a floodplain by a surface
disposal site was deleted from the final
regulation because that requirement is
addressed by a management practice in
the final part 503 regulation. The
management practice requires that an
active sewage sludge unit not restrict
the flow of a base flood.
By definition, a floodplain is the
lowland and relatively flat area
inundated by a base flood. Not reducing
the temporary water storage capacity of
a floodplain means not reducing the
temporary storage capacity of the area
inundated by the base flood. This is the
same as not restricting the flow of a base
flood. Because these two requirements
address the same issue, the general
requirement in the proposal concerning
not reducing the temporary storage
capacity of a floodplain was deleted
from the final regulation. As mentioned
above, the requirement not to restrict
the flow of a base flow is a management
practice in the final part 503 regulation.
The requirements in the proposed
regulation concerning threatened or
endangered species, restriction of the
flow of a base flood, seismic impact
zone, distance from a fault or fracture,
location in a wetland, and runoff from
a 24-hour, 25-year storm event are
classified as management practices
rather than general requirements in the
final part 503 regulation.
The final part 503 regulation contains
four general requirements for placement
of sewage sludge on a surface disposal
site. The first requirement is that no
person shall place sewage sludge on a
surface disposal site unless the
requirements for the sewage sludge and
for the surface disposal site in this
subpart are met. EPA concluded that, in
most cases, the person who places
sewage sludge on a surface disposal site
will be a treatment worker. However,
they may be some situations where
some other person places sewage sludge
on a surface disposal site. This general
requirement applies to any person who
places sewage sludge on a surface
disposal site.
The second general requirement
concerns active sewage sludge units that
must close. This requirement applies to
an active sewage sludge unit located
within 60 meters of a fault or stress
fracture with displacement in Holocene
time; located in an unstable area; or
located in a wetland, except as provided
in a permit issued pursuant to either
section 402 or 404 of the CWA, as
amended. The Agency concluded that to
protect public health and the
environment from reasonably
anticipated adverse effects of pollutants
in sewage sludge, no additional amount
of sewage sludge should be placed on
those active sewage sludge units and
that those active sewage sludge units
should close by [insert one year after the
effective date of this part], unless, in the
case of an active sewage sludge unit
located within 60 meters of a fault or
stress fracture with displacement in
Holocene time, otherwise specified by
the permitting authority. The permitting
authority may conclude after further
review that an active sewage sludge unit
located within 60 meters of the above
fault or stress fracture need not close.
One year was chosen for the time period
within which the above active sewage
sludge units should close because that
is the compliance period for the final
part 503 regulation specified in section
405(d) of the Clean Water Act, as
amended.
The third general requirement in this
subpart is that the owner/operator of an
active sewage sludge unit must submit
a written closure and post closure plan
to the permitting authority 180 days
prior to the date that the active sewage
sludge unit closes. The plan must
discuss how the active sewage sludge
unit will be closed. Also included in
this general requirement is the
minimum information that should be
included in the closure plan.
The last general requirement in this
subpart of the final regulation requires
the owner of the surface disposal site to
provide written notification to the
subsequent owner of the surface
disposal site. That notification must
indicate that sewage sludge was placed
on the land. EPA concluded that the
-------
9342 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
subsequent owner of a surface disposal
sito should know that sewage sludge
was placed on the land so that they can
bocomo aware of any requirements that
result from placement of sewage sludge
on tha land (e.g., to monitor methane
gas for three years after the last active
sowago sludge unit in a surface disposal
unit closes).
Pollutant Limits—Other Than Domestic
Septage (Section 503.23)
Pollutant limits in the final part 503
regulation for sewage sludge (other than
domestic septage) placed on a surface
disposal site are expressed as pollutant
concentrations. The pollutant
concentrations protect public health and
the environment from reasonably
anticipated adverse effects of arsenic,
chromium, and nickel in the sewage
sludge. These pollutants were identified
by the Agency as pollutants that affect
public health and the environment
adversely when sewage sludge is placed
on a surface disposal site. The final rule
does not establish pollutant limits for
organic pollutants and some inorganic
pollutants for which the Agency
proposed pollutant limits. An
explanation of why limits are not
established in the final regulation for
those pollutants are presented in the
technical support document for the part
503 surface disposal requirements.
There are no pollutant limits in this
subpart for domestic septage placed on
an active sewage sludge unit because
tho Agency concluded they are not
needed to protect public health and the
environment when domestic septage is
placed on an active sewage sludge unit.
This is discussed further in the
technical support document for the part
503 surface disposal requirements.
When an active sewage sludge unit
does not have a liner and leachate
collection system, the allowable
pollutant concentrations in the sewage
sludge are presented in Table 1 of
section 503.23 in the final regulation.
Pollutant concentrations in Table 1 of
section 503.23 are based on the results
of an exposure assessment for the
ground-water and vapor pathways. For
tho ground-water pathway, the
assessment assumes that the MCL for a
pollutant is not exceeded 150 meters
from the boundary for the active sewage
sludge unit. The 150-meter distance is
tho distance used in the model for the
ground-water exposure assessment for
active sewage sludge units.
Tho final part 503 regulation requires
that the actual distance from the active
sowage sludge unit boundary to the
surface disposal site property line be
used to determine the allowable
concentration for each pollutant listed
in Table 1 of section 503.23. This
applies when (1) an active sewage
sludge unit does not have a liner and
leachate collection system and (2) the
active sewage sludge unit boundary is
less than 150 meters from the property
line of the surface disposal site. When
the actual distance is less than 150
meters, the allowable pollutant
concentrations may be different. Table 2
of section 503.23 contains the
concentration for the pollutants for
different unit boundary to property line
distances.
The final part 503 regulation includes
an alternative to the pollutant
concentrations discussed above for an
active sewage sludge unit that does not
have a liner and leachate collection.
When requested by the owner/operator
of a surface disposal site at the time of
permit application, site-specific
pollutant limits may be developed
under the final regulation for an active
sewage sludge unit without a liner and
leachate collection system if the existing
values for site parameters specified by
the permitting authority are different
from the values for those parameters
used to develop the pollutant limits in
Table 1 of section 503.23. In addition,
the permitting authority must determine
that site-specific pollutant limits are
appropriate for the active sewage sludge
unit. An important aspect of these
conditions is that the permitting
authority will specify the site
parameters that can be used to develop
a rationale for site-specific pollutant
limits. Examples of the site parameters
are depth to ground water and soil type.
If the permitting authority agrees that
site-specific pollutant limits are
appropriate, the limits must be based on
the results of a site-specific assessment,
as specified by the permitting authority,
or must be equal to the existing
concentration of the pollutant in the
sewage sludge that will be placed on the
active sewage sludge unit. The lower of
the above two values shall be the limit
for the pollutant that cannot be
exceeded in the sewage sludge.
When an active sewage sludge unit
has a liner and leachate collection
system, the liner retards the movement
of pollutants in sewage sludge to the
ground water. Results of the ground-
water pathway exposure assessment for
an active sewage sludge unit with a
liner and leachate collection system
indicate that, because of the impact of
the liner, sewage sludge with essentially
an unlimited concentration of the
inorganic pollutants can be placed on
the active sewage sludge unit. The liner
ensures that the inorganic pollutants do
not reach the ground water. For this
reason, there are no pollutant limits for
arsenic, cadmium, chromium, copper,
lead, mercury, and nickel for an active
sewage sludge unit with a liner and
leachate collection system in the final
part 503 regulation. There also are no
pollutant limits for organic pollutants
for sewage sludge placed on an active
sewage sludge unit with a liner and
leachate collection system in part 503
because all organic pollutants were
deleted from the final part 503
regulation.
Management Practices (Section 503.24)
The management practices for a
surface disposal of sewage sludge in the
proposed part 503 regulation are
included in the final part 503 regulation
with some editorial changes. In
addition, several new management
practices were added to the final
regulation.
The final regulation provides that
placement of sewage sludge on an active
sewage sludge unit is prohibited if it is
likely to adversely affect a threatened or
endangered species listed under section
4 of the Endangered Species Act or its
designated critical habitat (§ 503.24(a)).
EPA will develop guidance to carry out
this provision consistent with the
Endangered Species Act.
The second management practice
requires that an active sewage sludge
unit not restrict the flow of a base flood.
A base flood is a flood that has a one
percent chance of occurring in any
given year (i.e., a flood with a
magnitude equalled once in 100 years).
Thus, an active sewage sludge unit
cannot restrict the flow in an area that
carries the 100-year flood. This
management practice reduces the
potential for the area that carries the
100-year flood to experience problems
related to the location of the surface
disposal site (e.g., restriction of the
flow) in that area. It also protects the
surface disposal site and sewage sludge
placed on active sewage sludge units
from the impacts of a base flood.
Flood insurance rate maps (FIRM)
developed by the Federal Emergency
Management Agency (FEMA) should be
used to determine whether an active
sewage sludge unit is located in an area
that carries the base flood (i.e., the 100-
year floodplain). FEMA has developed
maps for approximately 99 percent of
the flood-prone communities in the
United States. Other sources of
information on the 100-year floodplain
include the U.S. Army Corps of
Engineers, the Soil Conservation
Service, the National Oceanic and
Atmospheric Administration, the U.S.
Geologic Survey, the Bureau of Land
Management, the Bureau of
Reclamation, the Tennessee Valley
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9343
Authority, and State and local flood
control agencies.
The third management practice
requires that an active sewage sludge
unit be designed to withstand the
maximum recorded horizontal ground
level acceleration when an active
sewage sludge unit is located in a
seismic impact zone. One purpose of
this management practice is to protect
the foundation of an active sewage
sludge unit from cracks caused by
ground motion that could lead to
collapse of the active sewage sludge
unit. Maps depicting the potential
seismic activity in the United States at
a constant probability are available from
the U.S. Geological Survey.
The fourth management practice
requires that an active sewage sludge
unit be located 60 meters or more from
a fault that has displacement in
Holocene time, unless otherwise
specified by the permitting authority.
The Holocene is a geologic time, known
as an epoch, that extends from the end
of the Pleistocene to the present
(approximately the last 11,000 years).
Geologic evidence indicates that
faults that moved in recent times (i.e.,
during the last 11,000 years) are most
likely to move in the future. Faults that
moved in Holocene time are easier to
identify and date than are older faults
because this epoch produced
recognizable geological deposits. The
U.S. Geological Survey mapped the
location of Holocene faults in the
United States in 1978. Maps of
identified Holocene faults in the United
States also are available from the States
of California and Nevada.
EPA is prohibiting the location of an
active sewage sludge unit within 60
meters of a Holocene fault, unless
otherwise specified by the permitting
authority, because results of studies
suggest that most of deformation takes
place within that distance. Effects of the
deformation decrease rapidly as
distance from the fault increases. The
permitting authority may allow an
active sewage sludge unit to be located
within 60 meters of a Holocene fault
after concluding that public health and
the environment are protected if an
active sewage sludge unit is located
within that distance. This is consistent
with the approach taken in 40 CFR part
258 for municipal solid waste landfills.
The fifth management practice
requires that an active sewage sludge
unit not be located in an unstable area.
An unstable area is an area of land
subject to natural or human-induced
forces that may damage the structural
components of the active sewage sludge.
The purpose of this management
practice is to protect the structural
components (e.g., the foundation) of an
active sewage sludge unit from forces
that could damage the components. For
example, when the foundation of an
active sewage sludge unit fails, sewage
sludge could be released and cause
harm to the environment. This also is
the reason that part 503 regulation
requires that an active sewage sludge
unit located in an unstable area close
within one year of the effective date of
the regulation.
To determine whether an area is
unstable, the following factors should be
considered, among other things: (1) Soil
conditions that cause differential
settling; (2) geologic or geomorphologic
features such as areas prone to mass
movement, Karst terrains, or fissures; (3)
surface areas weakened by the
withdrawal of oil, gas, or water; and (4)
other features that indicate protective
measures cannot be designed to
withstand a natural event such as a
volcanic eruption.
The management practice concerning
not locating an active sewage sludge
unit in an unstable area replaces the
general requirement in the proposed
part 503 regulation concerning location
of an active sewage sludge unit in areas
where adequate support exists for the
structural components of the sewage
sludge unit. The Agency concluded that
the management practice and general
requirement provide the same
protection. For this reason, there in no
need to have both requirements in the
final part 503 regulation.
Editorial changes were made to the
management practice concerning
location of an active sewage sludge unit
in a wetland. The final part 503
regulation requires that an active sewage
sludge unit not be located in a wetland,
except as provided in a permit issued
pursuant to either section 402 or 404 of
the CWA, as amended.
Editorial changes also were made to
the management practice concerning
runoff from a 24-hour, 25-year storm
event. These changes clarify that the 24-
hour, 25-year storm event is from a
storm with a frequency of occurrence of
25 years and that the collection system
must have the capacity to handle run-
off from the 24-hour, 25-year storm
event. The runoff from this storm event
must be collected and disposed in
accordance with National Pollutant
Discharge Elimination System permit
requirements and any other applicable
requirements. This management
practice protects surface waters from
pollutants in the run-off. The surface
water pathway was not evaluated in the
exposure assessment used to develop
the pollutant limits for sewage sludge
placed on a surface disposal site.
The Agency chose the 24-hour, 25-
year storm event for this management
practice to be consistent with the
requirements for hazardous waste
landfills in 40 CFR 264.301(g) and the
requirements for municipal solid waste
landfills in 40 CFR 258.26(a)(2). Both of
these provisions require that runoff from
the 24-hour, 25-year storm event be
collected and controlled. For the final
part 503 regulation, control of the runoff
means disposed in accordance with the
applicable requirements.
Water that runs on an active sewage
sludge unit was considered during the
development of the pollutant
concentrations for the ground-water
pathway in the surface disposal
exposure assessment. For this reason,
part 503 does not have a requirement
concerning water that runs on an active
sewage sludge unit.
Other management practices in the
final part 503 regulation address
collection and treatment of leachate,
concern for the build-up of methane gas
in the air inside a structure within a
surface disposal site and in the air at the
property line of a surface disposal site,
growing of crops, grazing of animals,
restricting public access to a surface
disposal site, and contamination of an
aquifer. These are discussed below.
As mentioned above, because a liner
retards the movement of pollutants in
sewage sludge to the ground water,
results of the ground-water pathway
analysis for an active sewage sludge unit
with a liner and leachate collection
system indicate that sewage sludge with
essentially an unlimited concentration
of inorganic pollutants can be placed on
an active sewage sludge unit that has a
well-maintained liner and leachate
collection system. For this reason, there
are no pollutant limits for inorganic
pollutants for an active sewage sludge
unit with a liner and leachate collection
system. The liner insures that the
inorganic pollutants do not reach the
ground water.
The part 503 regulation requires that
the leachate collection system for a
sewage sludge unit with a liner and
leachate collection system be operated
and maintained for the period that the
sewage sludge unit is active and for
three years after the sewage sludge unit
closes. This management practice
ensures that the leachate collection
system is operated and maintained.
Because the Agency has no pollutant
limits for an active sewage sludge unit
that has a liner and leachate collection
system, protection of ground water
obviously depends on proper operation
of the unit, including the leachate
collection system, to prevent pollutant
build-up and in the event of liner
-------
9344 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
failure, a treat to ground water. EPA
chose to require that the leachate
collection system be operated and
maintained for three years after the
sewage sludge unit closes because that
is the period that the leachate has to be
collected. This is discussed further
below.
The final regulation requires that the
loachate from a sewage sludge unit that
has a liner and leachate collection
system be collected and disposed in
accordance with the applicable
requirements for the period the sewage
sludge unit is active and for three years
after the sewage sludge unit closes. This
management practice is included in the
final part 503 regulation to prevent
damage to the liner caused by hydraulic
pressure from the leachate. The pressure
is reduced when the leachate is
collected and removed from the active
sewage sludge unit.
The three-year period after a sewage
sludge unit closes during which
leachate has to be collected and
disposed is based on the period that
methane gas must be monitored after a
sewage sludge unit closes. This is
discussed further below.
The final part 503 regulation contains
a management practice that addresses
the explosive potential of methane gas
generated in a sewage sludge unit.
Methane gas is generated in a sewage
sludge because of the anaerobic
conditions in the sewage sludge unit
that result when the sewage sludge is
covered. For this reason, the
management practice concerning
methane gas applies when a cover is
placed on an active sewage sludge unit
(e.g., to control vectors). When an active
sewage sludge unit is not covered, the
requirement to monitor methane gas
does not apply.
The methane gas management
practice protects public health from the
explosive potential of methane gas
generated during the stabilization of
sewage sludge after placement on a
sewage sludge unit. This is done by
limiting the percent of methane gas in
the air in any structure within the
property line of the surface disposal site
and by limiting the percent of methane
gas in the air at the property line of the
surface disposal site. The value for the
percent of methane gas in the air in any
structure within the property line of the
surface disposal site is 25 percent of the
lower explosive limit for methane gas,
which is the lowest percent by volume
of methane gas in air that propagates a
flame at 25 degrees Celsius and
atmospheric pressure. The value for the
percent of methane gas in the air at the
property line of a surface disposal site
is the lower explosive limit for methane.
Methane gas also must be monitored
for three years after a sewage sludge unit
closes when a final cover is placed on
the sewage sludge unit, unless
otherwise specified by the permitting
authority. This period is based on
results of a study titled "Pilot Scale
Evaluation of Sludge Landfilling—Four
Years of Operation" conducted in 1987
by EPA's Water Research Engineering
Laboratory in Cincinnati, Ohio. In this
study, sewage sludge was placed in
simulated landfill cells and methane
production was monitored for three
years and seven months. Results of this
study indicate that methane production
for the sewage sludge, which had been
stabilized in an anaerobic digester,
leveled off after approximately two
years. Because the study was a
laboratory simulation instead of a field
study, the Agency decided to increase to
the period that air must be monitored
for methane gas after a sewage sludge
unit closes to three years. The 10 year
period for monitoring methane gas in
the proposed part 503 regulation was
not used in the final part 503 regulation
because EPA concluded that a threo year
period is adequate to protect public
health and the environment based on
results of EPA's research. The Agency
concluded that for sewage sludge that
has been stabilized through either
anaerobic or aerobic digestion, the 10-
year period is not required.
As mentioned above, the period that
methane gas must be monitored after a
sewage sludge unit closes is three years,
unless specified otherwise by the
permitting authority. An example of
when a longer monitoring period may
be necessary is when a sewage sludge
that has not been treated in either an
anaerobic or aerobic process (e.g., a lime
stabilized sewage sludge) is placed in
the sewage sludge unit. In this case, the
potential for methane gas generation for
periods longer than three years exists.
For this reason, the permitting authority
may extend the period that the air in
structures within a surface disposal site
and at the property line of the surface
disposal site must be monitored for
methane gas.
Other management practices in this
subpart of the final regulation address
growing of crops, grazing of animals,
restricting public access to a surface
disposal site, and contamination of an
aquifer. Unless authorized by the
permitting authority, a food crop, a feed
crop, and a fiber crop cannot be grown
on an active sewage sludge unit. The
exposure assessment on which the
pollutant limits for surface disposal are
based did not consider growing crops on
the land where the sewage sludge is
placed. This management practice
protects public health and the
environment by prohibiting the growing
of food, feed, and fiber crops. However,
in certain circumstances, the permitting
authority may authorize the owner/
operator of a surface disposal site to
grow food crops, feed crops, and fiber
crops on an active sewage sludge unit
when alternative requirements (i.e.,
management practices) are imposed to
protect public health and the
environment.
The management practices concerning
animals grazing on an active sewage
sludge unit and public access
restrictions are included in the final
regulation because grazing of animals
and exposure of the public to sewage
sludge placed on the active sewage
sludge unit (e.g., ingestion of the sewage
sludge/soil mixture) were not
considered in the exposure assessment
used to develop the pollutant limits for
surface disposal. These management
practices are required, consequently, to
protect public heath and the
environment. In the case of grazing
animals, the permitting authority may
allow animals to graze on an active
sewage sludge unit when the owner/
operator of the surface disposal unit
demonstrates that through management
practices (e.g., monitor the
concentration of the pollutants in
animal products) public health and the
environment are protected from any
reasonably anticipated adverse effects of
pollutants in sewage sludge when
animals grazed.
Public access to a sewage sludge unit
must be restricted for the period the
sewage sludge unit is active and for
three years after the sewage sludge unit
closes. The three year period was
chosen to parallel the period that air
must be monitored for methane gas at a
closed sewage sludge unit that receives
a final cover. As mentioned above, the
reason for this management practice is
that the exposure assessment for the
surface disposal pollutant limits did not
consider contact by the public with the
sewage sludge placed on an active
sewage sludge unit (e.g., ingestion of the
sewage sludge/soil mixture). Protection
for the public is provided by restricting
access to the active sewage sludge unit.
In addition, this management practice
keeps the public away from an area
where the potential for explosions from
methane gas exists (i.e., when a final
cover is placed on the sewage sludge
unit.
The last management practice is that
the owner/operator of a surface disposal
site must demonstrate that the sewage
sludge does not contaminate an aquifer
after placement on an active sewage
sludge unit. The owner/operator may
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9345
demonstrate compliance in one of two
ways. Compliance may be demonstrated
through a ground-water monitoring
program. Alternatively, the owner/
operator may demonstrate compliance
through the certification of a qualified
ground-water scientist that an aquifer is
not contaminated.
When the owner/operator chooses to
demonstrate compliance through
ground-water monitoring, EPA
recommends that the owner/operator
develop a formal ground-water
monitoring plan. Such a plan should
include the following elements: (I] A
description of the location of the active
sewage sludge unit; (2) a description of
the ground-water monitoring system,
including the number, spacing, and
depths of the monitoring wells; (3) a
description of how the existing level of
nitrate in the ground water was
determined; and (4) the frequency of
sampling, sampling protocol, and
sample analytical methods.
In the preamble to the proposed part
503 rule, EPA explained its approach for
regulating monofills (i.e., surface
disposal sites in the final part 503
regulation). EPA stated that the proposal
modified and expanded the approach
used in the "Criteria for Classification of
Solid Waste Disposal Facilities and
Practice," 40 CFR part 257. The part 257
regulation, issued under the joint
authority of section 4004 of the
Research Conservation and Recovery
Act and section 405 of the Clean Water
Act, among other things, contained a
general prohibition (257.3—4) on the
contamination of an underground
drinking water source beyond the solid
waste boundary specified in accordance
with the requirements of the rule.
In the proposed part 503 rule, the
Agency adopted a prevention rather
than containment approach for the
proposed standards for sewage sludge
disposed in a monofill (i.e., surface
disposal site in the final part 503
regulation). As EPA explained, this
approach builds on the ground-water
protection concept by establishing
limits for sewage sludge on a pollutant-
by-pollutant basis to ensure that the
concentration of the pollutant reaching
the ground water does not cause the
MCL for a pollutant or other appropriate
standard to be exceeded in the ground
water. EPA concluded that controlling
pollutants at the source was more
protective and equitable to prevent
sewage sludge contamination of the
ground water. The proposed part 503
rule established pollutant concentration
limits for 16 pollutants when sewage
sludge is disposed in a monofill.
The final part 503 regulation
promulgated today for sewage sludge
disposed in a surface disposal site is
based on the approach in the proposed
part 503 rule. Based on available
scientific and technical information,
EPA concluded that when the pollutant
concentrations in today's rule are not
exceeded, the probability is small that
pollutants in the sewage sludge placed
on a surface disposal site will migrate to
the ground water, especially at levels
that cause the MCLs to be exceeded in
the ground water. Consequently, the
part 503 standards for surface disposal
sites replace 40 CFR part 257
requirements for sewage sludge
disposed on a surface disposal site,
except for nitrate.
In the proposed part 503 rule, EPA
requested comment on whether EPA
should retain the generic prohibition on
contamination of the ground water
provided in part 257 as an additional
protective measure and check on the
efficacy of the pollutant-specific sewage
sludge pollutant limits. EPA concluded
that retention of the prohibition in part
257 is generally not required because
the Agency has identified the pollutants
that present the greatest potential for
adversely affecting public health and
the environment when sewage sludge is
placed on active sewage sludge units.
These pollutants were evaluated and
assessed for determining the appropriate
standards promulgated here today.
However, one pollutant for which EPA
has established an MCL that numerous
commenters suggested may present a
problem for ground-water
contamination was not evaluated:
Nitrate. For this pollutant, EPA decided
to retain the general prohibition in part
257 on contamination of underground
drinking water sources (i.e.,
contaminate an aquifer). The last
general requirement in the surface
disposal subpart incorporates the
existing requirement in part 257
prohibiting nitrate contamination.
As explained above, EPA adopted a
preventive policy in establishing today's
surface disposal standards, which are
designed to ensure that contamination
of the ground water does not occur. For
this reason, the part 503 rule does not
require ground-water monitoring to
establish the absence of contamination
and, if and when contamination of the
ground water is identified, does not
require corrective action to clean up the
ground water or to take other measures
to protect public health and the
environment. The proposed part 503
rule had requested comment on whether
ground-water monitoring and corrective
action should back-stop EPA's pollution
prevention approach.
Since EPA first proposed the sewage
sludge use or disposal standards, EPA
has developed a formal statement of
ground-water protection principles in a
document titled "Protecting the Nation's
Ground Water: EPA's Strategy for the
1990s" (EPA Publication 21Z-1020, July
1991). This policy addresses approaches
to preventing contamination and clean-
up of contaminated ground water,
including early detection monitoring
and recognition of the primary role of
States in ground water protection. The
policy concludes that development of a
"Comprehensive State Ground Water
Protection Program" (CSGWPP) is the
most coherent current approach to draw
together the many Federal ground water
protection authorities administered by
States and to implement these programs
in a more effective, efficient and
coordinated manner. At this time, EPA
is in the process of preparing detailed
guidance for CSGWPPs under various
Federal legislative statutes addressing
water quality management and ground
water protection. As envisioned, under
a CSGWPP, States will develop and
implement ground-water protection
programs tailored to their unique
hydrogeologic settings and institutional
arrangements, including establishing
priorities for uses of ground water for
drinking water supply and ecological
sustainability.
At the present time, 25 States have
already adopted Wellhead Protection
Programs under the Safe Drinking Water
Act to protect wellhead areas within
their jurisdiction from contaminants
that may have an adverse effect on
public health. Some of these programs
may include various control measures,
including siting restrictions on the
location of facilities. Additionally,
approximately 30 States have, or are in
the process of developing, a system for
categorizing State ground water by use
or vulnerability. EPA expects that the
policies adopted in the Wellhead
Protection Programs and State
classification systems will be
incorporated in the CSGWPPs. EPA
urges those contemplating disposal of
sewage sludge on surface disposal sites
to contact their State authorities to
determine any restrictions under State
Wellhead Protection Programs or State
ground-water classification schemes (or
the State CSGWPP when developed)
that may impose further limitations on
either the siting or operation of surface
disposal sites.
The standards EPA has adopted
today, as noted above, include certain
restrictions on the siting of surface
disposal sites to protect ground water.
In Round Two, EPA will consider
whether also to include in the surface
disposal standards an explicit
requirement to comply with either State
-------
9346 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
siting, ground-water monitoring or other
requirements that are part of a State's
Wellhead Protection Program or
applicable State CSGWPP.
Pathogens and Vector Attraction
Reduction (Section 503.25)
The pathogen requirements in the
final part 503 regulation for sewage
sludge (other than domestic septage)
placed an active sewage sludge unit are
similar to the existing requirements for
the disposal of sewage sludge on the
land in 40 CFR part 257. Sewage sludge
(other than domestic septage) placed on
a surface disposal site must meet either
the Class A pathogen requirements in
503.32(a) or the Class B pathogen
requirements in 503.32(8), except the
site restrictions in 503.32(b)(5), unless a
cover is placed on the active sewage
sludge unit at the end of each operating
day. When a daily cover is placed on an
active sewage sludge unit, the sewage
sludge does not have to meet a separate
pathogen requirement. The daily cover
isolates the sewage sludge and allows
the environment to reduce the
pathogens in the sewage sludge.
The site restrictions in 503.33(b)(5) do
not have to he met when the sewage
sludge meets the Class B pathogen
requirements because site restrictions
are already imposed on an active sewage
sludge unit for other than pathogen
reduction. Management practices that
already address site restrictions are
included in this subpart because, as
previously mentioned, the exposure
assessment for the surface disposal
pollutant limits did not address
activities such as growing of crops,
grazing of animals, and exposure to the
sewage sludge by the public.
Domestic septage placed on a surface
disposal site does not have to meet a
specific pathogen requirement. The
existing requirements in part 257 for
septic tank pumpings indicate that
septic tank pumpings applied to the
land must be treated in a Process to
Significantly Reduce Pathogens (PSRP)
or restrictions concerning grazing of
animals and access by the public must
be imposed on the site where the
domestic septage is applied. Because
site restrictions for those two activities,
as well as a restriction on the growing
of crops, are imposed on all active
sewage sludge units for other than
pathogen reduction, the part 257 site
restrictions for applying domestic
septage to the land are met at every
active sewage sludge unit. For this
reason, domestic septage placed on an
active sewage sludge unit does not have
to meet an additional pathogen
requirement.
The vector attraction reduction
requirements in the final part 503
regulation also are similar to the part
257 vector attraction reduction
requirements for sewage sludge
disposed on the land. Part 257 requires
that the sewage sludge be covered daily
or that other appropriate techniques be
used to reduce vector attraction. The
final part 503 regulations requires that
1 of 10 vector attraction reduction
requirements (i.e., "other techniques")
be met when sewage sludge (other than
domestic septage) is placed on an active
sewage sludge unit or that daily cover
be placed on the active sewage sludge
unit. When daily cover is placed on an
active sewage sludge unit, the sewage
sludge does not have to meet a separate
pathogen requirement. The daily cover
prevents access to the sewage sludge by
vectors.
Vector attraction reduction is
achieved when domestic septage is
placed on a surface disposal site when
the domestic septage is injected below
the land surface, incorporated into the
soil, or the pH of the domestic septage
is raised to a certain level and remains
at that level for 30 minutes (i.e., "other
techniques"), or when the active sewage
sludge unit receives a daily cover. The
"other techniques" for domestic septage
are limited to injection, incorporation,
and pH adjustment because the Agency
does not believe that "other techniques"
available for sewage sludge (e.g., volatile
solids reduction and percent moisture)
are feasible for each container of
domestic septage placed on an active
sewage sludge unit. When daily cover is
placed on an active sewage sludge unit,
access to domestic septage placed on the
unit by vectors is prevented.
Frequency of Monitoring (Section
503.26)
The final part 503 regulation contains
the frequency of monitoring
requirements for pollutants in sewage
sludge (other than domestic septage)
placed on an active sewage sludge unit,
pathogen density requirements, and
vector attraction reduction
requirements. The permitting authority
may establish more stringent frequency
of monitoring requirements, if
necessary. The frequency of monitoring
for sewage sludge placed on an active
sewage sludge unit is based on the
amount of sewage sludge placed on an
active sewage sludge unit annually.
Calculation of the amounts of sewage
sludge in the various ranges in table 1
of section 503.26 is discussed in the
section on land application in this
preamble. The calculations also are
discussed in the technical support
document for the part 503 surface
disposal requirements.
The final part 503 regulation also
allows the permitting authority to
reduce the frequency of monitoring for
pollutants and for the pathogen density
requirements in 503.32(a)(5)(ii) and
503.32(a)(5)(iii) after two years of
monitoring at the frequencies in table 1
of 503.26. In deciding whether to reduce
the minimum frequency of monitoring,
the permitting authority shall consider,
among other things, the variability of
the pollutant concentrations over the
two years, the magnitude of the
pollutant concentrations, and the
frequency of detection of enteric viruses
and viable helminth ova in the sewage
sludge. Note that only the permitting
authority can reduce the frequency of
monitoring.
As mentioned above, the frequency of
monitoring for the enteric viruses
density requirements in 503.32(a)(5)(ii)
and the viable helminth ova density
requirements in 503.32(a)(5)(iii) may be
reduced. The reasons the Agency
concluded the frequency of monitoring
for these requirements may be reduced
are discussed in the section on land
application in this preamble.
The final part 503 regulation requires
that each container (e.g., each tank truck
load) of domestic septage placed on a
surface disposal site be monitored for
pH when vector attraction reduction is
achieved by raising the pH of the
domestic septage. Each container must
be monitored because there is no other
way to know whether the domestic
septage meets the pH requirement.
The final regulation also requires that
methane gas in all structures within a
surface disposal site and at the property
line of the surface disposal site be
monitored continuously under certain
situations. For this reason, the
frequency of monitoring for methane gas
for those situation is continuously.
Recordkeeping (Section 503.27)
The final part 503 regulation contains
recordkeeping requirements for sewage
sludge (other than domestic septage)
and for domestic septage placed on a
surface disposal site. The person who
prepares the sewage sludge must
develop certain information (e.g., the
concentration of pollutants in the
sewage sludge) and retain the
information for five years. In addition,
the owner/operator of a surface disposal
site also must develop certain
information (e.g., a certification that the
management practices for an active
sewage sludge unit are met) and retain
that information for five years.
When domestic septage is placed on
an active sewage sludge unit, the person
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9347
who applies the domestic septage must
develop certain information and the
owner/operator of the surface disposal
site must develop certain information.
In both cases, the information has to be
retained for five years.
Recordkeeping requirements are
included in this subpart because the
regulation is self-implementing (i.e., the
requirements apply even when a person
does not receive a permit). Without the
requirement to keep records, there is no
way to demonstrate that the part 503
requirements are met.
Reporting (Section 503.28)
The part 503 regulation requires Class
I sludge management facilities, POTWs
with a design flow rate equal to or
greater than 1 million gallons per day,
and POTWs that serve 10,000 people or
more to report the information
developed in 503.27(a) for sewage
sludge (other than domestic septage) to
permitting authority once every 365
days. Only Class I sludge management
facilities, POTWs with a design flow
rate equal to or greater than 1 million
gallons per day, and POTWs that serve
10,000 people or more must report
information for the reasons discussed in
the land application section in today's
preamble.
Pathogens and Vector Attraction
Reduction (Subpart D)
This section of the preamble discusses
pathogen and vector attraction
reduction requirements in the final part
503 regulation for sewage sludge that is
applied to the land or placed on an
active sewage sludge unit. More details
on these requirements may be obtained
from the technical support document for
the part 503 pathogen and vector
attraction reduction requirements.
Scope (Section 503.30)
This subpart in the final part 503
regulations establishes the requirements
that must be met for a sewage sludge to
classified either Class A or Class B with
respect to pathogens and the alternative
vector attraction reduction
requirements. Either the Class A or
Class B pathogen requirements must be
met and one of the alternative vector
attraction reduction requirements must
be met when sewage sludge is applied
to the land or placed on a surface
disposal site. The circumstance under
which either the Class A or Class B
requirements must be met (e.g., sewage
sludge sold or given away in a bag or
other container for application to the
land must meet the Class A
requirements) is addressed in the part
503 subparts on land application
(subpart B) and surface disposal
(subpart C).
This subpart also contains site
restrictions that must be met when a
Class B sewage sludge is applied to the
land and the pathogen requirements for
domestic septage applied to agricultural
land, forest, or a reclamation site. As
discussed previously, there are no
pathogen requirements in the final part
503 regulation for domestic septage
placed on a surface disposal site.
Special Definitions (Section 503.31)
Five of the 11 special definitions in
this subpart in the proposed regulation
were deleted from the final part 503
regulation. Also, six new definitions
were added to the final part 503
regulation and editorial changes were
made to the definitions in the proposal
that are included in the final regulation.
Definitions for the following terms are
in the final regulation: aerobic digestion,
anaerobic digestion, density of
microorganisms, land with a high
potential for public exposure, land with
a low potential for public exposure,
pathogenic organisms, pH, specific
oxygen uptake rate, total solids,
unstabilized solids, vector attraction,
and volatile solids. The definitions that
were deleted from and added to the
final regulation are discussed below.
The terms "food crops" and "feed
crops" are defined in the general
definitions in the final regulation. For
this reason, the definitions for those
terms are not included in this subpart of
the final regulation.
The term "indicator organism" is not
used in the final part 503 regulation. For
this reason, the definition of indicator
organism was deleted from the final
regulation.
Pathogen reduction was defined in
the proposed regulation as the
elimination or reduction of pathogenic
bacteria (Salmonella sp.), protozoa,
viruses, and helminth ova in sewage
sludge. This definition was deleted from
the final regulation because the
pathogen requirements in the final
regulation are not expressed in terms of
quantity of pathogen reduction. They
are expressed in terms of values that
cannot be exceeded in the sewage
sludge.
In the proposed regulation, the
pathogen requirements were expressed
in terms of per gram of volatile
suspended solids. Comments on the
proposal indicated that those
requirements should be expressed in
terms of total solids because volatile
suspended solids change in the sewage
sludge during treatment. The Agency
agrees with the comments and is
expressing the pathogen requirements in
the final regulation in terms of per gram
of total solids (dry weight basis).
Because the term "volatile suspended
solids" is not used in the final
regulation, the definition for that term
was deleted from the final part 503
regulation.
The final part 503 regulation includes
a definition for land with a high
potential for public exposure because
the site restrictions for a Class B sewage
sludge that is applied to the land differ
depending on the potential exposure of
the public to the land. Land with a high
potential for public exposure is land
used frequently by the public. This
includes, but is not limited to, parks,
ball fields, and a reclamation site
located in a populated area (e.g., a
construction site). This type of land has
a stringent public access restriction (i.e.,
one year) when a Class B sewage sludge
is applied to the land.
Land with a low potential for public
exposure is land used infrequently by
the public. This includes, but is not
limited to, agricultural land and forest.
The Agency does not believe that the
public will use these types of land
frequently. Note that the public does not
include people who apply the sewage
sludge to the land or farm workers.
The final part 503 regulation also
includes a definition of pathogenic
organisms. Pathogenic organisms are
disease-causing organisms. These
include, but are not limited to, certain
bacteria, protozoa, viruses, and viable
helminth ova.
The definition of total solids is in the
final regulation because, as mentioned
above, the requirements for pathogenic
organisms in sewage sludge are
expressed in terms of per gram of total
solids in the sewage sludge. Total solids
are the materials in sewage sludge that
remain as residue when the sewage
sludge is dried at 103 to 105 degrees
Celsius.
The final part 503 regulation includes
the definition of unstabilized solids
because two of the vector attraction
reduction requirements in the final
regulation depend on whether the
sewage sludge that is used or disposed
of contains unstabilized solids.
Unstabilized solids are organic materials
in sewage sludge that have not been
decomposed biochemically or have been
treated only with chemicals (e.g., lime
stabilized).
Pathogens (Section 503.32)
There are several differences between
the pathogen requirements in the
proposed part 503 regulation and the
pathogen requirements in the final
regulation. These changes are discussed
below.
-------
9348 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Tho first change concerns the
pathogen requirement for protozoa in
the proposal. Protozoa are no longer
included as one of the organisms subject
to pathogen requirements because of the
lack of an analytical method for
protozoa. In addition, EPA concluded
that protozoa are unlikely to survive
wastowatcr treatment and sewage sludge
treatment processes and, thus, should
not cause a reasonably anticipated
adverse effect in sewage sludge that is
used or disposed of.
Second, the unit of measurement for
density of pathogenic organisms was
changed for volatile suspended solids to
total solids. As mentioned previously,
several commenters stated that the use
of volatile suspended solids is not
appropriate because the volatile
suspended solids concentration changes
significantly when the sewage sludge is
treated. The Agency agrees and changed
the unit of measurement to total solids.
A third change is not expressing the
focal coliform requirements in terms of
a log reduction. Several commenters on
the proposed regulation stated that
requiring a log reduction may not
protect public health and the
environment. For example, reducing the
focal coliform from a log of 6 (i.e.,
1,000,000} to a log of 4 (i.e., 10,000) is
a two log reduction. A reduction for log
of 4 (i.O., 10,000} to log of 2 (i.e., 100)
also is a two log reduction. The final
fecal coliform density is different,
however, for each example (10,000
versus 100). The Agency agrees with the
commenters and eliminated the log
reduction requirement in the final part
503 regulation. Instead, the final
regulation requires that the density of
focal coliform in the sewage sludge be
equal to or less than a specific value.
Another change is the elimination of
the requirement to reduce fecal
streptococci in the sewage sludge. EPA
concluded that the use of fecal coliform
is sufficient to indicate the presence of
pathogenic organisms in the sewage
sludge. A requirement for both fecal
streptococci and fecal coliform is
redundant. Fecal coliform was selected
for the final part 503 regulation because
an analytical method exists for fecal
coliform and because treatment works
conduct fecal coliform analyses
routinely.
One of the major changes in the
pathogen requirements in the final
regulation is that the regulation only has
two classes of pathogen requirements
instead of the three classes in the
proposed regulation. Several
commenters indicated that the
requirements in the proposal for Class B
and Class C are essentially the same.
The Agency agrees with the commenters
and only included Class A and Class B
pathogen requirements in the final
regulation. Changes also were made to
the Class A and Class B pathogen
requirements and to the site restrictions
when a Class B sewage sludge is applied
to the land.
The final regulation requires that the
Class A pathogen requirements be met
either prior to or at the same time
certain vector attraction reduction
requirements are met. Typically, after
the Class A pathogen requirement is
met, the sewage sludge is left without an
adequate density of predator or
competitive organisms to compete with
pathogenic bacteria such as Salmonella
sp. bacteria. As a result, regrowth of
pathogenic bacteria in the sewage
sludge will occur if a small number of
those bacteria survive treatment or
when bacteria are introduced into the
sewage sludge inadvertently. When
vector attraction reduction precedes
treatment for pathogens, regrowth of the
pathogenic bacteria can occur. When
vector attraction reduction occurs after
treatment for pathogens, competitive
organisms are re-introduced into the
sewage sludge during vector attraction
reduction and regrowth of pathogenic
bacteria is inhibited.
The above requirement does not apply
when the vector attraction requirement
concerning adjustment of sewage sludge
pH is met. In that case, alkali material
used to raise the pH remains in the
sewage sludge after treatment. This
material inhibits growth of pathogenic
bacteria even when the density of
predator or competitive organisms is too
low to resist regrowth of the bacteria.
For this reason, the order of vector
attraction reduction and pathogen
treatment is not relevant when the
vector attraction reduction requirement
is met by raising the pH of the sewage
sludge to 12 or higher with alkali
addition and, without the addition of
more alkali, the pH of the mixture
remains at 12 or higher for two hours
and then remains at 11.5 or higher for
an additional 22 hours.
The above requirement concerning
the order of pathogen reduction also
does not apply when vector attraction
reduction is achieved by drying the
sewage sludge to the specified percent
solid values. In this case, EPA
concluded that re-growth of Salmonella
sp. bacteria is not a problem.
The requirement to reduce pathogens
either prior to or at the same time as
vector attraction is reduced applies only
to a sewage sludge that meets the Class
A pathogen requirements. A Class B
sewage sludge usually has an adequate
density of predator and competitive
organisms even when the vector
attraction reduction requirement is met
before the Class B pathogen requirement
is met.
The final part 503 has six alternative
requirements that can be met for a
sewage sludge to be classified Class A
with respect to pathogens. Each
alternative requirement is discussed
below.
The objective of the alternative
pathogen reduction requirements is to
protect public health and the
environment from the reasonably
anticipated adverse effects of pathogens
in sewage sludge that is used or
disposed. The Agency concluded that
the best way to meet that objective is for
the sewage sludge that is used or
disposed to meet certain pathogen
density requirements and for that
sewage sludge to meet other pathogen
density requirements at the time of use
or disposal. Sewage sludge generated at
every treatment works and each material
derived from sewage sludge should be
analyzed for pathogens to show that the
density of pathogenic organisms in the
sewage sludge or material derived from
sewage sludge are below the specified
value.
The first Class A pathogen alternative
in the final part 503 regulation is based
on raising the temperature of the sewage
sludge to a specific value and keeping
the temperature at that value for a
specific time. Salmonella sp. bacteria,
enteric viruses, and viable helminth ova
in the sewage sludge are expected to be
reduced to acceptable levels (i.e., to
below detectable levels) when the
temperature and time requirements are
met.
For the final part 503 regulation, the
temperature and time requirements vary
depending on the percent solids in the
sewage sludge. When the percent solids r
is equal to or greater than seven percent
and the sewage sludge is not heated by
warmed gases or an immiscible liquid,
the temperature must be 50 degrees
Celsius or higher and the time period
must be 20 minutes or longer. The
temperature and time period are
determined using equation (2) in the
final regulation. The 20 minute
minimum time period helps ensure
uniform heating is achieved throughout
the sewage sludge.
When me percent solids in the sewage
sludge is equal to or greater than seven
percent and the sewage sludge is heated
by warmed gases or an immiscible
liquid, the temperature must be 50
degrees Celsius or higher and the time
period must be 15 seconds or longer.
The temperature and time period in this
case also are determined using equation
(2) in the final regulation. Sewage
sludge heated in this manner usually is
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9349
in the form of small droplets or particles
(e.g., less than one millimeter in
diameter) that are dispersed throughout
the gas or liquid. Because of this small
size, uniform heating can be achieved in
a short time at a high temperature.
When the percent solids of the sewage
sludge is less than seven percent and
the sewage sludge is heated for 15
seconds or longer, but for less than 30
minutes, the temperature and time are
determined using equation (2). Uniform
heating of this sewage sludge is
achieved under these conditions.
When the percent solids of the sewage
sludge is less than seven percent, the
temperature of the sewage sludge is 50
degrees Celsius or higher, and time
period is 30 minutes or longer, the
temperature and time period are
determined using equation (3) in the
final regulation. The Agency concluded
that uniform heating of sewage sludge
that has a percent solids of less than
seven can be achieved at lower
temperatures for shorter times. The
lower percent solids allows the heat to
be dispersed throughout the sewage
sludge in a shorter time and not as
much heat (i.e., high temperature) is
needed to ensure that the temperature of
the solids in the sewage sludge is raised
to an adequate level.
To use the temperature and time
equations, either the temperature at
which the sewage sludge will be
maintained or the time the temperature
will be maintained has to be known.
The known value is then used in the
appropriate equation to obtain the other
value.
In addition to the temperature and
time requirements, this alternative
requires that either the density of fecal
coliform in the sewage sludge or the
density of Salmonella sp. bacteria in the
sewage sludge must be below a specific
value at the time the sewage sludge is
used or disposed, at the time the sewage
sludge is prepared for sale or give away
in a bag or other container for
application to the land, or at the time
the sewage sludge is prepared to meet
the requirements in 503.10 concerning
sewage sludge that is not subject to the
general requirements and management
practices in the land application
subpart. This insures that Salmonella
sp. bacteria do not regrow in the sewage
sludge subsequent to when the
temperature of the sewage sludge is
raised to the specific level for the
specific period. EPA will provide more
guidance on the terms "at the time of
use or disposal", "at the time the
sewage sludge is prepared for sale or
give away in a bag or other container for
application to the land", and "at the
time the sewage sludge is prepared to
meet the requirements in 503.10
concerning sewage sludges not subject
to the general requirements and
management practices in the land
application subpart".
The Agency concluded that when the
temperature of the sewage sludge is
raised to the value determined using
equation (2) or equation (3) and
maintained at that value for the
specified period, the densities of
Salmonella sp. bacteria, enteric viruses
and viable helminth ova in the sewage
are reduced to below detectable levels.
Because enteric viruses and viable
helminth ova are not expected to regrow
over time, there is no requirement in
this Class A alternative to measure the
density of those organisms in the
sewage sludge after the temperature and
time requirements are met.
The second alternative in the final
part 503 regulation for a sewage sludge
to classified Class A with respect to
pathogens also requires that the density
of fecal coliform or the density of
Salmonella sp. bacteria in the sewage
sludge be below a specified level at the
time the sewage sludge is used or
disposed, at the time the sewage sludge
is prepared for sale or give away in a bag
or other container for application to the
land, or at the time the sewage sludge
is prepared to meet the requirements in
503.10 concerning the exemption of the
sewage sludge from the general
requirements and management practices
in the land application subpart. This
requirement ensures that Salmonella,
sp. bacteria does not regrow in the
sewage sludge between the time the
sewage sludge is treated and the time
the sewage sludge is used or disposed.
In addition to the regrowth
requirement, the second Class A
alternative requires that the pH of the
sewage sludge that is used or disposed
be raised to above 12 and remain above
12 for 72 hours. During at least 12 hours
of the 72-hour period, the temperature
of the sewage sludge has to be greater
than 52 degrees Celsius. At the end of
the 72-hour period, the sewage sludge
must be air dried to achieve a percent
solids of greater than 50 percent. When
these requirements are met, the Agency
concluded that the density of
Salmonella, sp. bacteria, enteric viruses,
and viable helminth ova in the sewage
sludge are reduced to below detectable
levels.
The requirements in Alternative 2 are
a generic description of a process that
has been classified a Process To Further
Reduce Pathogens (PFRP) by EPA.
Because that process has already been
classified a PFRP (i.e., a process that
produces a Class A sewage sludge), the
Agency concluded that sewage sludges
that meet these requirements should be
classified Class A. For this reason, this
Class A alternative was added to the
final part 503 regulation.
The third alternative in the final
regulation for a sewage sludge to be
classified Class A with respect to
pathogens also addresses the regrowth
issue by requiring that the density of
either fecal coliform or Salmonella, sp.
bacteria in the sewage sludge be below
a specified value at the time the sewage
sludge is used or disposed, at the time
the sewage sludge is prepared for sale or
give away in a bag or other container for
application to the land, or at the time
the sewage sludge is prepared to meet
the requirements in 503.10 concerning
sewage sludge not subject to the general
requirements and management practices
in the land application subpart. In
addition, this alternative requires that
the sewage sludge be monitored for
enteric viruses and viable helminth ova
prior to being treated in a pathogen
process. The number of times the
sewage sludge must be monitored for
those microorganisms varies, as
discussed below.
As mentioned above, enteric viruses
must be monitored in the sewage sludge
in the influent to the pathogen treatment
process during each monitoring episode
for the sewage sludge. When enteric
viruses are not found in influent (i.e.,
the density of enteric viruses is less than
one Plaque-forming Unit per four grams
of total solids), the sewage sludge is
Class A with respect to enteric viruses
until the next monitoring episode for
the sewage sludge.
When the density of enteric viruses in
the influent to the pathogen treatment
process is equal to or greater than one
Plaque-forming Unit per four ;jrams of
total solids, the density of the enteric
viruses in the sewage sludge that is used
or disposed (i.e., after the pathogen
treatment process) must be below one
Plaque-forming Unit per four grams of
total solids. In addition, values for the
operating parameters for the pathogen
treatment process that produces the
sewage sludge that meets the enteric
virus density requirement must be
documented. At this time, the sewage
sludge is Class A with respect to enteric
viruses.
For the sewage sludge to continue to
be Class A with respect to enteric
viruses, the values for the process
operating parameters must be consistent
with the values documented above at all
times. Although the term "consistent
with" allows die actual values for the
operating parameter to be different from
the documented values for the operating
parameters, the Agency does not expect
-------
9350
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
there will bo a large variation in those
values.
Tho approach discussed above for
enteric viruses also is part of this
alternative for viable helminth ova. The
sowogo sludge is Class A with respect to
viable helminth ova when viable
helminth ova are not found (i.e., less
than one per four grams of total solids)
in the influent to the pathogen treatment
process. When viable helminth ova are
found in the influent, the density of
viable helminth ova in the sewage
sludge that is used or disposed must be
loss than one per four grams of total
solids and the operating parameters for
the pathogen treatment process must be
documented for the sewage sludge to be
Class A with respect to viable helminth
ova. After the viable helminth ova
reduction is demonstrated, values for
the process operating parameters must
be consistent with the documented
values for those parameters for the
sowogo sludge to continue to be
classified Class A with respect to viable
helminth ova.
Alternative 3 is designed to reduce
the analytical costs for pathogenic
organisms after pathogen reduction is
demonstrated for the pathogen
treatment process. The Agency
concluded that after pathogen reduction
is demonstrated for a process, the
effluent from the process (i.e., the
sewage sludge that is used or disposed)
does not have to be monitored for the
pathogenic organisms as long as the
process operating parameters are
consistent with the documented values.
This is similar to the temperature and
time requirement in Alternative 1. In
Alternative 1, as long as the temperature
and time requirement is met, pathogens
are reduced to acceptable levels. In this
alternative, when the values for
operating parameters are consistent with
the documented values after pathogen
reduction is demonstrated, enteric
viruses and viable helminth ova are
reduced to below detectable levels.
The Agency recognizes that, under
this alternative, the sewage sludge may
have to be analyzed for enteric viruses
and viable helminth ova during each
monitoring episode when enteric
viruses and viable helminth ova are
never found in the influent to the
pathogen treatment process. The Agency
also recognizes that the analyses for
these organisms are costly and that only
a limited number of laboratories can
perform those analyses. For these
reasons, the permitting authority may
reduce the frequency of monitoring for
those organisms in the final port 503
regulation after two years of monitoring
at the specified frequency. In deciding
whether to reduce the frequency of
monitoring for those two
microorganisms in the influent to the
pathogen treatment process, the
permitting authority may consider,
among other things, the frequency of
detection of enteric viruses and viable
helminth ova during the two year
period.
The fourth alternative for a sewage
sludge to be classified Class A with
respect to pathogens is for the sewage
sludge to be monitored for fecal
coliform or Salmonella sp. bacteria,
enteric viruses, and viable helminth ova
at the time the sewage sludge is used or
disposed, at the time the sewage sludge
is prepared for sale or give away in a bag
or other container for application to the
land, or at the time the sewage sludge
is prepared to meet the requirements in
503.10 concerning exemption from the
general requirements and management
practices in the land application
subpart. When the density values for the
above organisms in the sewage sludge
are equal to or less than the values for
those organisms in this alternative, the
sewage sludge is Class A with respect to
pathogens.
The fourth Class A pathogen
alternative can be used for sewage
sludges for which there is no historical
knowledge about how the sewage sludge
was treated. For example, when a
sewage sludge has been stored for a
period and is now going to be used or
disposed, this alternative can be used to
determine whether the sewage sludge is
Class A with respect to pathogens.
Because there is no information about
how the sewage sludge was treated prior
to storage, one of the first three Class A
pathogen alternatives cannot be used to
determine whether the sewage sludge is
Class A. Under this alternative, samples
of the sewage sludge can be collected at
the time of use or disposal and analyzed
to determine whether the density values
for the pathogenic organisms are equal
to or less than the density values for
those organisms in today's regulation.
When the density values for the
organisms are equal to or less than the
values in this alternative, the sewage
sludge is Class A. The density values in
this alternative for fecal coliform or
Salmonella sp. bacteria, enteric viruses,
and viable helminth ova are the same as
the density values for those organisms
in Alternative 3.
The fifth and sixth alternatives also
address the regrowth issue by requiring
that the density of either fecal coliform
or Salmonella sp. bacteria in the sewage
sludge be below a specified value at the
time the sewage sludge is used or
disposed, at the time the sewage sludge
is prepared for sale or give away in a bag
or other container for application to the
land, or at the time the sewage sludge
is prepared to meet the requirements in
503.10 concerning sewage sludge that is
not subject to the general requirements
and management practices in the land
application subpart. In addition, under
the fifth alternative, a sewage sludge
must be treated in a Process to Further
Reduce Pathogens (PFRP) to be
classified Class A. Processes classified
PFRPs are described in appendix B.
These processes are the same processes
described in appendix II to 40 CFR part
257. The descriptions in Appendix B
were edited to remove any requirements
for vector attraction (e.g., reduce volatile
solids by 38 percent). A sewage sludge
must meet one of the vector attraction
requirements discussed below in
addition to the pathogen requirements
in the final part 503 regulation.
For the sixth Class A pathogen
alternative, the regrowth requirements
mentioned above must be met and the
sewage sludge must be treated in a
propess that is equivalent to a Process to
Further Reduce Pathogens, as
determined by the permitting authority.
The Agency currently has a group that
advises the permitting authority
whether a process is equivalent to a
PFRP. That group is the Pathogen
Equivalency Committee (PEC). The final
decision on whether a process is
equivalent to PFRP is made by the
permitting authority based on
recommendations by the PEC. The
sewage sludge also must meet one of the
vector attraction reduction requirements
discussed below in addition to this
pathogen requirement.
The Class B pathogen requirements in
the final part 503 regulation also are
different from the Class B requirements
in the proposed regulation. In the
proposal, either of two requirements
had to be met. First, the densities of
Salmonella sp. bacteria and viruses in
the influent to the treatment works had
to be reduced to below specific values.
The second requirement was that when
the wastewater is treated in physical or
biological processes and the sewage
sludge generated in those processes is
treated in a physical, biological, or
chemical addition process or stored for
at least one day, the densities of fecal
coliform and fecal streptococci in the
sewage sludge had to be below a
specific value. In addition, site
restrictions were imposed when a Class
B sewage sludge was applied to the
land.
There are three alternatives in the
final part 503 regulation for a sewage
sludge to be classified Class B with
respect to pathogens. The first Class B
alternative requires that seven samples
of sewage sludge that is used or
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9351
disposed be collected each time the
sewage sludge is monitored. In addition,
the geometric mean of the density of
fecal coliform (expressed as either Most
Probable Number or Colony Forming
Units) in those samples must be less
than 2,000,000. A geometric mean is the
anti-logarithm of the arithmetic average
of the logarithms for a certain number
of values (in this case, values for the
seven samples).
The second Class B alternative is that
the sewage sludge be treated in a
Process to Significantly Reduce
Pathogens (PSRP). Appendix B contains
a description of processes currently
classified as PSRPs. Those processes are
the same as the PSRP processes
described in appendix II of 40 CFR part
257 with some editorial changes. One
editorial change is that the vector
attraction reduction requirements in the
Appendix II descriptions were deleted
in today's description. As mentioned
above, a sewage sludge must meet one
of the vector attraction reduction
requirements discussed below in
addition to the pathogen requirements
in the final part 503 regulation.
The third Class B pathogen alternative
in the final regulation is that the sewage
sludge that is used or disposed be
treated in a process that is equivalent to
a Process to Significantly Reduce
Pathogens, as determined by the
permitting authority. The Pathogen
Equivalency Committee (PEC) discussed
above helps the permitting authority
decide whether a process is equivalent
to a PSRP. The final decision on such
a determination is the responsibility of
the permitting authority.
The final part 503 regulation also
contains site restrictions that must be
met when a Class B sewage sludge is
applied to the land. These restrictions
provide time for the natural
environment to reduce the pathogenic
organisms in the sewage sludge.
Site restrictions in the final regulation
for a Class B sewage sludge that is
applied to the land are different from
the site restrictions for that practice in
the proposed regulation. These
differences are discussed below.
The first site restriction pertains to
food crops that touch the sewage
sludge/soil mixture and are above
ground totally. The proposed regulation
restricted the growing of those crops for
18 months after the sewage sludge is
applied to the land. The final regulation
restricts the harvesting of those crops for
14 months after the application of the
sewage sludge. The 14 month harvesting
restriction assumes that crops will not
be grown for 12 months and that the
crops grow for two months before
harvesting. This access restriction
prevents exposure to viable helminth
ova that survive for long periods in the
soils on the land surface when the
viable helminth ova are sheltered from
sunlight and desiccation.
The second restriction pertains to
food crops with harvested parts below
the surface of the ground (i.e., root
crops). The proposed regulation
restricted the growing of those crops for
five years after application of the sewage
sludge. The final regulation contains
two requirements for root crops
depending on how long the sewage
sludge remains on the land surface
before incorporation into the soil.
The first requirement restricts the
harvesting of food crops with harvested
parts below the surface of the land for
20 months after application of the
sewage sludge when the sewage sludge
remains on the land surface for four
months prior to incorporation into the
soil. The Agency concluded that
exposure of the sewage sludge to the
natural environment during the four
month period promotes die-off of viable
helminth ova, which is the most
persistent pathogen in a sewage sludge/
soil mixture. This justifies the reduction
in the period before a root crop can be
harvested discussed below. The 20
month restriction assumes that food
crops with harvested parts below the
surface of the land will not be grown for
18 months and that the crops grow for
two months before harvesting.
The other restriction for food crops
with harvested parts below the surface
of the land is that those crops cannot be
harvested for 38 months after sewage
sludge is applied to the land when the
sewage sludge does not remain on the
land surface for four months after
application. In this case, the pathogenic
organisms are not reduced as much by
the natural environment (i.e., air and
sunlight). For this reason, the restriction
on harvesting root crops is 38 months to
allow for die-off of viable helminth ova.
This restriction assumes that the crops
will not be grown for three years after
application of the sewage sludge and
that the crops grow for two months
before they are harvested.
The site restrictions in the proposed
regulation concerning the harvesting of
feed crops and the grazing of animals
are the same in the final regulation.
Feed crops shall not be harvested and
animals shall not be grazed for 30 days
after application of sewage sludge to the
land. The Agency concluded this is a
long enough period to allow die-off of
pathogens that may affect animals. This
restriction also applies to the harvesting
of food crops and fiber crops because
the 30-day exposure to the environment
is needed to allow die-off of pathogens
that may affect humans.
A new site restriction concerning the
harvesting of turf was added to the final
regulation. The purpose of this site
restriction is to prevent public exposure
to turf grown on land where a Class B
sewage sludge is applied. Most likely,
turf grown on the land will be used on
a lawn or on land with a high potential
for public exposure (e.g., a public
contact site). To restrict public exposure
to that turf for one year, which is the
same public access restriction for land
with a high potential for public
exposure (see below), the final part 503
regulation requires that turf grown on
land where a Class B sewage sludge is
applied not be harvested for one year
after application of the sewage sludge
when the harvested turf is placed on a
lawn or on land with a high potential
for public exposure, unless otherwise
specified by the permitting authority.
The public access restriction for land
on which a Class B sewage sludge is
applied in the proposed regulation was
expanded in the final part 503
regulation. The restriction in the final
regulation recognizes that the potential
for exposure to the sewage sludge is not
the same for all types of land.
Some lands have a high potential for
exposure to the public. Those lands
include, but are not limited to, parks,
ball fields, and a reclamation site
located in a populated area (e.g., a
construction site next to a high school).
When a Class B sewage sludge is
applied to those types of land, the final
part 503 regulation requires that public
access be restricted for one year after
application of the sewage sludge. This
period allows the pathogenic organisms
to die off in the natural environment.
Other lands have a low potential for
exposure because they are used
infrequently by the public. These lands
include, but are not limited to, land
used for silviculture purposes,
agricultural land, and a reclamation site
located in an unpopulated area (e.g., a
strip mine). Public access to lands with
a low potential for exposure has to be
restricted for 30 days after application of
sewage sludge to the land.
The final part 503 regulation also
contains alternative pathogen
requirements for domestic septage
applied to agricultural land, forest, or a
reclamation site. The first requirement
is that the site restrictions discussed
above be met. When these restrictions
are met, the domestic septage does not
have to meet an additional pathogen
requirement.
The second requirement is to raise the
pH of the domestic septage to 12 or
higher by alkali addition and, without
-------
9352 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
the addition of more alkali, maintain the
pH at 12 or higher for 30 minutes. In
addition, the site restrictions discussed
above concerning harvesting of crops
must be met. The site restrictions are
noedod because domestic septage is not
considered Class A with respect to
pathogens after the pH requirement is
mot. Site restrictions are needed to
allow die-off of pathogens through
exposure to the environment before
crops are harvested.
The above pH requirement is based on
the results of a study conducted at the
University of Wisconsin on pathogens
in domestic septage (Ronner, Amy B.
and Doan O, Oliver, Ph.D., "Disinfection
of Viruses in Septic Tank and Holding
Waste by Calcium Hydroxide (Lime)",
Small Scale Waste Management Project,
University of Wisconsin, Madison,
Wisconsin, June 1987). The Agency
concluded that when the above pH
requirement is met and site restrictions
concerning harvesting of crops are met,
public health and the environment are
protected from the pathogenic
organisms in domestic septage.
Vector Attraction Reduction (Section
503.33)
The vector attraction reduction
requirements in the proposed regulation
are adopted in the final regulation.
Editorial changes were made to several
of the proposed requirements. In
addition, several new vector attraction
reduction requirements were added to
the final part 503 regulation. The vector
attraction reduction requirements in the
final regulation address: the reduction
in the mass of volatile solids in sewage
sludge that is used or disposed; an
additional reduction in the mass of
volatile solids for an anaerobically
digested sewage sludge that is digested
anaerobically for an additional period in
the laboratory; an additional reduction
in the mass of volatile solids for an
ncrobicolly digested sewage sludge that
is digested aerobically for an additional
period in the laboratory; the specific
oxygen uptake rate for a sewage sludge
digested aerobically; a sewage sludge
treated in on aerobic process for a
specific period during which the
temperature of the sewage sludge is
raised; an increase in the pH of the
sewage sludge; the percent solids of the
sewage sludge; injection of the sewage
sludge below the land surface;
incorporation of the sewage sludge into
the soil; cover for a surface disposal site;
and pH adjustment for domestic
soptage. These alternative requirements
are discussed below.
Not all of the vector attraction
reduction requirements in the final part
503 regulation pertain to the different
sewage sludge use or disposal practices.
For example, when sewage sludge is
sold or given away in a bag or other
container for application to the land, the
vector attraction reduction requirement
concerning injection below the land
surface does not apply. Section 503.33
(a) in the final part 503 regulation
indicates which vector attraction
reduction requirements pertain to which
use or disposal practices.
One vector attraction reduction
requirement is that the mass of volatile
solids in the sewage sludge be reduced
by a minimum of 38 percent. The 38
percent reduction is determined by
subtracting the mass of volatile solids in
the sewage sludge that is used or
disposed from the mass of volatile
solids in the influent to the sewage
sludge digestion process and dividing
that value by the mass of volatile solids
in the influent to the sewage sludge
digestion process. This value is then
multiplied by 100 to obtain the percent
reduction. By reducing the volatile
solids of the sewage sludge, the "source
of food" for a vector is reduced, which
reduces the attractiveness of the sewage
sludge to the vector.
Editorial changes were made to the
proposed vector attraction reduction
requirement concerning a 17 percent
volatile solids reduction for
anaerobically digested sewage sludge
that is digested anaerobically further in
the laboratory. These changes clarify
that the additional anaerobic digestion
should occur in a bench-scale unit in
the laboratory for 40 days at a
temperature between 30 and 37 degrees
Celsius and that the 17 percent
reduction or less is the reduction of the
volatile solids in the sewage sludge at
the beginning of the 40 day period. This
alternative requirement is included in
the final regulation because the volatile
solids content of some sewage sludges is
low before the sewage sludge is treated
in the anaerobic digester. In this case, it
is very difficult to achieve a 38 percent
volatile solids reduction during
digestion. The Agency concluded that
when the percent volatile solids
reduction after the additional digestion
period is 17 percent or less, vectors will
not be attracted to the sewage sludge.
The above requirement for additional
treatment of a sample of the sewage
sludge in the laboratory also pertains to
an aerobically digested sewage sludge.
A similar requirement is included in the
final regulation for an aerobically
digested sewage sludge.
When an aerobically digested sewage
sludge cannot meet the above 38 percent
volatile solids reduction requirement, a
portion of the previously digested
sewage sludge that has a percent solids
of two percent or less can be digested
aerobically in the laboratory in a bench-
scale unit for 30 additional days at 20
degrees Celsius. When at the end of the
30 days, the volatile solids in the
sewage sludge at the beginning of that
period is reduced by less than 15
percent, vector attraction reduction is
achieved for the sewage sludge.
The percent solids requirement (i.e.,
two percent or less) and temperature
requirement are part of the above
alternative because they affect the rate
of digestion. When the percent solids is
greater than two percent, the rate of
digestion is slower than the rate of
digestion when the percent solids is two
percent or less. To ensure that the
sewage sludge is digested fully during
the 30 day period, the percent solids
requirement and the temperature
requirement are included in this
alternative. A percent solids
requirement is not included in the
above alternative for additional
digestion of an anaerobically digested
sewage sludge because percent solids
does not affect the rate of digestion
during anaerobic digestion of a sewage
sludge.
The percent volatile solids reduction
in the above two alternative vector
attraction reduction requirements is
different for anaerobic digestion (i.e., 17
percent) and aerobic digestion (i.e., 15
percent). These percentages are based
on experiences with the different types
of digested sewage sludge.
The proposed vector attraction
reduction requirement concerning the
specific oxygen uptake rate (SOUR) also
was changed in the final regulation. The
changes are a different value for SOUR
and the addition of a temperature
requirement. In the final regulation, the
SOUR of the sewage sludge treated in an
aerobic process has to be equal to or less
than 1.5 milligrams (instead of 1.0 in the
proposal) of oxygen per hour per gram
of total solids at 20 degrees Celsius for
the sewage sludge to meet the vector
attraction reduction requirement.
After reviewing the available
information and comments on the
proposal, the Agency concluded that
vector attraction reduction can be
achieved when the value for SOUR is
equal to or less than 1.5. The
temperature requirement is included in
the SOUR vector attraction reduction
requirement because the temperature of
the sewage sludge affects the rate of
digestion. The Agency concluded that
for the sewage sludge to digested fully
during aerobic digestion, the
temperature of the sewage sludge
should be 20 degrees Celsius.
Another vector attraction reduction
requirement was added to the final
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9353
regulation for sewage sludge treated in
an aerobic process. This requirement
addresses the vector attraction of sewage
sludges treated in processes such as
composting and aerobic digestion. EPA
concluded, based on available
information, that when a sewage sludge
is treated in an aerobic process for 14
days or longer during which time the
temperature of the sewage sludge is
higher than 40 degrees Celsius and the
average temperature is higher than 45
degrees Celsius, volatile solids in the
sewage sludge are reduced to a level
that reduces the attractiveness of the
sewage sludge to vectors.
The vector attraction reduction
requirement in the proposal concerning
raising the pH of the sewage sludge and
maintaining the elevated pH for a period
is the same in the final regulation. Only
editorial changes were made to this
requirement for the final regulation.
Raising the pH of the sewage sludge
reduces bacterial activity in the sewage
sludge. This results in a reduction in the
putrefaction of the sewage sludge,
which reduces the odors from the
sewage sludge. Because of the reduction
in odors, vectors are not attracted to the
sewage sludge.
One of the new vector attraction
reduction requirements in the final part
503 regulation concerns the percent
solids of the sewage sludge. In the
proposal, when the percent solids of the
sewage sludge was 75 or greater, based
on the moisture and solids content of
the sewage sludge prior to mixing with
other materials, the vector attraction
reduction requirement was met. The
final part 503 regulation contains two
percent solids requirements for vector
attraction reduction.
One of the percent solids
requirements is the same as in the
requirement in the proposal (i.e., 75
percent). This requirement only applies,
however, when the sewage sludge does
not contain unstabilized solids
generated in a primary wastewater
treatment process. When the sewage
sludge contains unstabilized solids
generated in a primary wastewater
treatment process, the percent solids of
the sewage sludge has to be equal to or
greater than 90 percent. This change
was made because the Agency is
concerned that regrowth of Salmonella
sp. bacteria may occur when the sewage
sludge contains unstabilized solids such
as food products that Salmonella sp.
bacteria can use for nutrients. When the
percent solids of the sewage sludge is
equal to or greater than 90, EPA
concluded that the regrowth problem is
mitigated even if the sewage sludge
contains unstabilized solids.
The vector attraction reduction
requirement in the proposal concerning
injection of the sewage sludge below the
land surface was edited and expanded
hi the final regulation. First, this vector
attraction reduction requirement now
clarifies that no significant amount of
sewage sludge can be visible on the land
surface within one hour after the sewage
sludge is injected. Second, this
requirement addresses the time during
which a Class A sewage sludge has to
be injected after discharge from the
pathogen reduction process. Injection of
a Class A sewage sludge within a
specific time period was addressed in
the Class A pathogen requirement in the
proposal. The Agency chose to include
this requirement in the section on vector
attraction reduction in the final
regulation to make the final part 503
regulation consistent.
In addition to changing the location of
the vector attraction requirement for the
injection of a Class A sewage sludge, the
requirement itself was changed. The
proposed regulation required that the
density of fecal coliform and fecal
streptococci in the Class A sewage
sludge not exceed three logarithms per
gram of volatile suspended solids prior
to injection. EPA decided to change this
requirement to "the sewage sludge shall
be injected below the land surface
within eight hours after the sewage
sludge is discharged from the pathogen
reduction process(es)". The Agency
concluded that significant regrowth of
Salmonella sp. bacteria will not occur
when the sewage sludge is injected
within the eight hour period.
Another vector attraction reduction
requirement in the final part 503
regulation concerns incorporation of
sewage sludge into the soil. EPA
concluded that vector attraction
reduction is minimal during the first six
hours after sewage sludge is applied to
or placed on the land surface. After that
time, the potential for vector attraction
increases. For this reason, this vector
attraction reduction requirement
requires that the sewage sludge be
incorporated into the soil within six
hours after application to or placement
on the land. Incorporation into the soil
reduces the opportunity for vectors to
contact the sewage sludge.
The vector attraction reduction
requirement concerning incorporation
of the sewage sludge into the soil also
requires that sewage sludge that is Class
A with respect to pathogens be applied
to or placed on the land within eight
hours after being discharged from the
pathogen treatment process. After that,
the sewage sludge must be incorporated
into the soil within six hours after being
applied to or placed on the land. The
purpose of this requirement is to ensure
that regrowth of Salmonella sp. bacteria
do not occur between the time the
sewage sludge is discharged from the
pathogen treatment process and the time
the sewage sludge is applied to or
placed on the land.
Also included in the final part 503
regulation is an alternative vector
attraction reduction requirement when
sewage sludge is placed on an active
sewage sludge unit. When the sewage
sludge is covered with soil or other
material at the end of each operating
day, vector attraction reduction is
achieved. Vectors do not have the
opportunity to contact the sewage
sludge when the sewage sludge is
covered. This requirement was in the
subpart on monofills in the proposed
part 503 regulation. Because the
purpose of covering the sewage sludge
is to reduce vector attraction, the
Agency decided to include this
requirement in the section on vector
attraction reduction in the final part 503
regulation.
A new vector attraction reduction
requirement concerning domestic
septage also was added to the final
regulation. This requirement is in
response to comments that domestic
septage cannot meet the vector
attraction reduction requirement for
sewage sludge. To meet this new
requirement, the pH of the domestic
septage must be raised to 12 or higher
using alkali and, without the addition of
more alkali, must remain at 12 or higher
for 30 minutes. This requirement is
based on results from the University of
Wisconsin Study mentioned previously
in the discussion on the pathogen
requirements.
Incineration (Subpart E)
This part of today's preamble
discusses the requirements in the final
part 503 regulation for firing of sewage
sludge in a sewage sludge incinerator.
More details on these requirements may
be obtained from the technical support
document for the part 503 sewage
sludge incineration requirements.
Applicability (Section 503.40)
The applicability section for this
subpart in the final part 503 regulation
is the same, with the exception of some
editorial changes, as the applicability
section for this subpart in the proposed
regulation. This subpart applies to any
person who fires sewage sludge in a
sewage sludge incinerator, to a sewage
sludge incinerator, to sewage sludge
fired in a sewage sludge incinerator, and
to the exit gas from a sewage sludge
incinerator stack.
-------
9354 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Special Definitions (Section 503.41)
Definitions for the following terms are
included in this section of the final
regulation: Air pollution control device,
auxiliary fuel, control efficiency,
dispersion factor, fluidized bed
incinerator, incineration, hourly
average, monthly average, risk specific
concentration, sewage sludge feed rate,
sewage sludge incinerator, stack height,
total hydrocarbons, wet electrostatic
procipitator, and wet scrubber. The
definitions in this subpart discussed
below amplify and reinforce the
incineration requirements in the final
part 503 regulation.
Auxiliary fuel. The definition of
auxiliary fuel is included in the final
regulation because a sewage sludge
incinerator is defined as an incinerator
In which sewage sludge and auxiliary
fuel are fired. Auxiliary fuel is fuel used
to augment the fuel value of sewage
sludge. This includes, but is not limited
to, natural gas, fuel oil, coal, gas
generated during anaerobic digestion of
sewage sludge, or municipal solid waste
(not to exceed 30 percent of the sewage
sludge and auxiliary fuel together by dry
weight). Auxiliary fuel does not include
hazardous wastes.
As mentioned above, auxiliary fuel
maybe municipal solid waste if the
municipal solid waste is less than 30
percent by weight (dry weight basis) of
the material, including sewage sludge,
fired in the sewage sludge incinerator.
In that case, the part 503 requirements
for the incineration of sewage sludge in
a sewage sludge incinerator have to be
mot. When 30 percent or greater of the
material fired in an incinerator is
municipal solid wastes, the incinerator
is a municipal waste combustor and the
regulations that address firing of
materials in a municipal waste
combustor must be met.
Contra] efficiency. Control efficiency
is the mass of a pollutant in the sewage
sludge fed to an incinerator minus the
mass of that pollutant in the exit gas
from the incinerator stack divided by
the mass of the pollutant in the sewage
sludge fed to the incinerator. The final
regulation requires that control
efficiency be determined from a
performance test of the sewage sludge
incinerator, as specified by the
permitting authority.
Dispersion factor. The definition of
dispersion factor in the proposed
regulation is clarified in the final
regulation. Dispersion factor is the
increase in the ground level ambient air
concentration for a pollutant at a
specific distance from the sewage sludge
Incinerator stack because of the
incineration of sewage sludge divided
by the mass emission rate for the
pollutant from the sewage sludge
incinerator stack. The units for a
dispersion factor are micrograms per
cubic meter per gram per second.
Incineration. Incineration is the
combustion of organic matter and
inorganic matter in sewage sludge by
high temperatures in an enclosed
device. The phrase "controlled flame
combustion" is not included in that
definition because high temperatures
may be achieved in an enclosed device
without controlled flame combustion.
Today's definition ensures that the
requirements in the final regulation for
incineration apply to any enclosed
device in which organic material and
inorganic matter in sewage sludge are
combusted by high temperatures and
not just to those that employ controlled
flame combustion.
Hourly average. An hourly average is
the arithmetic mean of the number of
measurements taken during an hour. To
determine an hourly average, at least
two measurements must be taken during
the hour. This definition is in the final
regulation because this term is used in
the definition of a monthly average.
Monthly average. A monthly average
is the arithmetic mean of the hourly
averages for the hours a sewage sludge
incinerator operates during the month.
Note that only the hourly averages for
the hours a sewage sludge incinerator
operates during the month are used to
calculate a monthly average. This
definition is included in the final
regulation because the allowable total
hydrocarbons concentration in the exit
gas from a sewage sludge incinerator
stack is a monthly average
concentration.
Bisk specific concentration. Risk
specific concentration is the allowable
increase in the average daily ground
level ambient air concentration for a
pollutant from the incineration of
sewage sludge at or beyond the property
line of the site where the sewage sludge
incinerator is located. A risk specific
concentration is either provided in the
final regulation for each pollutant
controlled in this subpart, except total
hydrocarbons, or can be calculated
using an equation in the final
regulation.
Sewage sludge feed rate. The
difference in the definition of sewage
sludge feed rate in the proposal and the
definition in the final regulation is the
amount of sewage sludge fed to the
incinerator. The proposed regulation
indicated that the feed rate was either
the average amount of sewage sludge fed
to the incinerator or the design capacity
of the incinerator.
In the final part 503 regulation, the
feed rate is either the average daily
amount of sewage sludge fired for all
sewage sludge incinerators within the
property line of the site where the
sewage sludge incinerators are located
for the number of days in a 365 day
period that each incinerator operates, or
the average daily design capacity for all
of the sewage sludge incinerators within
the property line of the site where the
sewage sludge incinerators are located.
When there is more than one sewage
sludge incinerator located at a site, the
pollutant limits for each incinerator are
calculated using the same sewage sludge
feed rate.
When the design capacity of the
sewage sludge incinerators is not used
to determine the sewage sludge feed
rate, the average daily amount of sewage
sludge fired in all sewage sludge
incinerators is the sewage sludge feed
rate. This change clarifies how the
average daily amount should be
determined. This rate is based on the
average daily amount of sewage sludge
fired for the days in a 365 period that
each incinerator operates. This results
in an average daily amount of sewage
sludge fired based on actual operating
days for each incinerator. This value
would be lower if the days the
incinerators do not operate (i.e., zero
amount fired on those days) are
considered in developing the average
daily amount fired.
Sewage sludge incinerator. The
definition of sewage sludge incinerator
in the final part 503 regulation is an
incinerator in which sewage sludge and
auxiliary fuel are fired. The term
"auxiliary fuel" was added to today's
definition to clarify that a sewage sludge
incinerator is an incinerator in which
sewage sludge and auxiliary fuel are
fired. As mentioned previously,
hazardous wastes are not auxiliary fuel.
General Requirements (Section 503.42)
For the final part 503 rule, EPA
reorganized the general requirements
and management practices in the
proposal for subpart E. Only one of the
general requirements in this subpart for
die proposal is still a general
requirement in the final part 503
regulation; one is included in the
general provisions in the final part 503
regulation; four are management
practices in this subpart; one is
included in the section on pollutant
limits in this subpart; one is included in
a definition in the final regulation; one
is in the section on frequency of
monitoring in this subpart of the final
regulation; and one was deleted from
the final regulation. These changes are
discussed below.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9355
The first general requirement
concerns a person who fires sewage
sludge in a sewage sludge incinerator.
The final part 503 regulation requires
that no person shall fire sewage sludge
in a sewage sludge incinerator unless
the requirements in this subpart are met.
As mentioned above, this is the only
general requirement in the incineration
subpart.
The general requirement concerning
access to sewage sludge fed to a sewage
sludge incinerator was modified and is
included in 503.8—Sampling and
analysis. The general provision requires
that representative samples of sewage
sludge fired in a sewage sludge
incinerator be collected and analyzed.
EPA proposed general requirements
for this subpart concerning: (1) An
instrument that measures and records
the total hydrocarbons in the exit gas
from a sewage sludge incinerator stack;
(2) an instrument that measures and
records the oxygen content in the exit
gas from a sewage sludge incinerator
stack; (3) an instrument that measures
and records information used to
determine the moisture content in the
sewage sludge incinerator stack exit gas;
(4) an instrument that measures and
records combustion temperatures. These
proposed general requirements are
management practices in the final part
503 regulation.
One of the other proposed general
requirements required that a sewage
sludge incinerator comply with the
requirements promulgated under the
authority of the Clean Air Act in 40 CFR
61.30 through 61.34 for beryllium and
40 CFR 61.50 through 61.55 for
mercury. These requirements are now
included in the section on pollutant
limits in the final part 503 regulation.
This proposed general requirement also
required that the requirements in 40
CFR 60.150 through 60.154 for new
sources be met. The Agency decided not
to include this part of the proposed
general requirement in the final part 503
regulation because those requirements
are not needed to protect public health
and the environment from the
reasonably anticipated adverse effects of
pollutants in sewage sludge. Those
requirements still have to be met,
however. They are just not a
requirement in part 503.
Another general requirement in the
proposal required that the sewage
sludge feed rate for all incinerators
within the property line of the treatment
works be used to calculate the pollutant
limits for incineration of sewage sludge.
Because the definition of sewage sludge
feed rate in the final part 503 regulation
is based on the calculation for all
incinerators at the facility, the general
requirement was deleted from the final
regulation.
The general requirement in the
proposal concerning the monitoring
requirements are now included in a
separate section in the final regulation.
For this reason, this general requirement
was deleted from the final regulation.
Another general requirement in the
proposed regulation required that
incinerator ash be disposed in
accordance with the requirements in 40
CFR parts 257, 258, or 261 through 268,
as appropriate. Because the final part
503 regulation does not apply to
incinerator ash, the Agency decided not
to address the disposal of incinerator
ash in this subpart.
Pollutant Limits (Section 503.43)
Several changes were made in the
final part 503 regulation to the proposed
pollutant limits. These changes are
discussed below.
In the proposed regulation, equations
were presented to calculate pollutant
limits for beryllium and mercury. These
equations are deleted from the final
regulation. Instead, beryllium and
mercury in sewage sludge fired in a
sewage sludge incinerator are controlled
through the National Emission
Standards for each of those pollutants.
The final part 503 regulation requires
that firing of sewage sludge in a sewage
sludge incinerator shall not violate the
requirements in the National Emission
Standard for Beryllium in subpart C of
40 CFR part 61 and the National
Emission Standard for Mercury in
subpart E of 40 CFR part 61.
The proposed regulation also
contained equations used to establish
pollutant limits for lead, arsenic,
cadmium, chromium, and nickel. Those
equations are modified in the final
regulation. The equation in the final
regulation used to calculate the
pollutant limit for lead is:
C =
0.1x(NAAQS)x86,400
DFx(l-CE)xSF
Where:
C=Allowable daily concentration of lead in
milligrams per kilogram of total sewage
sludge solids (dry weight basis).
NAAQS=National Ambient Air Quality
Standard for lead in micrograms per
cubic meter.
DF=Dispersion factor in micrograms per
cubic meter per gram per second.
CE=Sewage sludge incinerator control
efficiency for lead in hundredths.
SF=Sewage sludge feed rate in metric tons
per day (dry weight basis).
The 0.1 value in the above equation
allocates 10 percent of the NAAQS for
lead to the firing of sewage sludge in a
sewage sludge incinerator. This is
discussed further in other parts of
today's preamble.
One of the terms in the above
equation is the control efficiency (i.e.,
percent removal of the pollutant) for the
sewage sludge incinerator. The value for
control efficiency could be obtained
from a table in the proposed regulation
(i.e., national value) or could be
determined from a performance test of
the incinerator (i.e., case-by-case limit).
The final regulation requires that the
control efficiency be obtained from a
performance test of the incinerator, as
specified by the permitting authority.
Consequently, the table in the proposal
with the control efficiencies used to
calculate the national pollutant limits
was deleted from the final part 503
regulation.
Another parameter in the above
equation is the dispersion factor. In the
proposal, the dispersion factor could be
obtained from a table in the proposed
regulation (i.e., used to calculate a
national limit) or could be determined
using an air dispersion model (i.e., used
to calculate a case-by-case limit), as
specified by the permitting authority.
Again, like control efficiency, the final
regulation requires that the dispersion
factor be determined specifically for the
site using either the height of the
incinerator stack or the creditable stack
height in an air dispersion model, as
specified by the permitting authority.
The final part 503 regulation does not
contain values for dispersion factor.
The above changes concerning
pollutant control efficiencies and
dispersion factors allow the actual
performance of the sewage sludge
incinerator for a particular sewage
sludge and the actual site conditions
(e.g., actual topography) to be
considered in developing the
incinerator control efficiency for a
pollutant and dispersion factor,
respectively. The Agency concluded
this is more appropriate than
prescribing the pollutant control
efficiencies and dispersion factors in the
final part 503 regulation.
The equation in the final regulation
used to calculate the pollutant limits for
arsenic, cadmium, chromium, and
nickel is:
C =
RSCX86.400
DFx(l-CE)xSF
Where:
C=Allowable daily concentration of
arsenic, cadmium, chromium, or nickel
in milligrams per kilogram of total
sewage sludge solids (dry weight basis).
-------
9356 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
CE«Sewago sludge incinerator control
efficiency for arsenic, cadmium,
chromium, or nickel in hundredths.
DF»DisporsIon factor in micrograms per
cubic motor per gram per second.
RSORisk specific concentration for a
pollutant in micrograms per cubic meter.
SF»So wage sludge feed rate in metric tons
por day (dry •weight).
As mentioned above, values for
control efficiency are determined from a
performance test of the incinerator, as
specified by the permitting authority.
The dispersion factor is determined
using either the incinerator stack height
or the creditable stack height in an air
dispersion model, as specified by the
permitting authority. The risk specific
concentration for arsenic, cadmium, and
nickel is obtained from a table in this
subpart of the final regulation.
In the proposed regulation, the value
for the risk specific concentration for
chromium was given in a table. In the
final part 503 regulation, the risk
specific concentration for chromium
either can be obtained from a table in
the final port 503 regulation or can be
calculated using an equation provided
in the regulation.
Different values for the risk specific
concentration for chromium are
presented in Table 2 of section 503.43
depending on the type of incinerator
with attendant air pollution control
devices used to fire the sewage sludge.
These values are based on data for the
different types of incinerators with
attendant air pollution control devices
and the percentage of hexavalent
chromium in the exit gas from the
sewage sludge incinerator stack. For
example, available information
indicates that the percentage of
hexavalent chromium in the stack exit
gas from a fluidized bed incinerator
with a wet scrubber and a wet
electrostatic precipitator is
approximately 3.8 percent. This
percentage \vas used to calculate the
risk specific concentration for
chromium in Table 2 of section 503.43
for that type of incinerator.
The percentage of hexavalent
chromium in the exit gas from a sewage
sludge incinerator is important because
the hexavalent chromium has the most
effect on public health. As the
percentage of hexavalent chromium
increases, the risk specific
concentration, which is the allowable
increase in the average daily ground
level ambient air concentration of a
pollutant from the incineration of
sewage sludge, for total chromium
decreases.
When the risk specific concentrations
in Table 2 of section 503.43 are not
used, the risk specific concentration for
chromium can be calculated using
equation (6) in the final regulation. The
value 0.0085 in equation (6) is the risk
specific concentration for chromium
when the percentage of hexavalent
chromium in total chromium emitted is
100 percent. To use the equation, the
percent of hexavalent chromium in the
exit gas from the sewage sludge
incinerator stack has to be measured.
That value is then used in the equation.
Operational Standard (Section 503.44)
Under the proposed rule, the
allowable emissions of total
hydrocarbons in the exit gas from the
sewage sludge incinerator stack were
controlled. This approach was adopted
because EPA concluded that it is
infeasible to establish a limit that
protect public health for each organic
pollutant in the exit gas. Consequently,
EPA proposed a risk-based operational
standard that limited total hydrocarbons
in the exit gas using site-specific factors.
In the final part 503 regulation, the
pollutant limit for total hydrocarbons is
similarly an operational standard. This
operational standard is based, however,
on the demonstrated performance of
sewage sludge incinerators using
available technology. The operational
standard includes a THC concentration
that cannot be exceeded in the exit gas
from the incinerator. The total
hydrocarbons concentration measured
in the stack exit gas must be corrected
for zero percent moisture and to seven
percent oxygen using equations
provided in the final regulation. The
corrected value cannot exceed the
monthly average concentration for total
hydrocarbons specified in the final
regulation.
The allowable THC concentration is a
monthly average. Such an average is
consistent with the assumptions made
in the cancer risk assessment that
supports the regulation. Implicit in the
monthly average are excursions that
recognize that the THC value may not be
met every second of every day. This is
satisfactory as long as the monthly
average does not exceed 100 parts per
million on a volumetric basis. EPA
concluded that in the case of sewage
sludge incinerators, the monthly average
THC concentration is appropriate.
As mentioned above, the operational
standard for THC in the final regulation
is based on the performance of an
incinerator with an instrument that
measures a "hot" THC. For this reason,
a management practice (i.e., 503.45(a))
is included in the final regulation that
requires THC to be measured using an
instrument that measures "hot" THC.
In the judgment of the Administrator
of EPA, the operational standard for
THC in the final regulation protects
public health from reasonable
anticipated adverse effects of organic
pollutants in the incinerator stack exit
gas when sewage sludge is fired in a
sewage sludge incinerator. More details
on how the risks associated with the
total hydrocarbons operational standard
were calculated are presented in part
VIII of this preamble.
Management Practices (Section 503.45)
The final part 503 regulation contains
seven management practices for the
firing of sewage sludge in a sewage
sludge incinerator. The management
practices are generally intended to
ensure that a sewage sludge incinerator
operates within the defined parameters
associated with the calculation of the
pollutant limits for inorganic pollutants
and with the achievement of the THC
regulatory level.
The first management practice
requires that an instrument that
measures and records the total
hydrocarbons concentration in the
sewage sludge incinerator stack exit gas
continuously be installed, calibrated,
operated, and maintained for each
sewage sludge incinerator. The total
hydrocarbons instrument must employ a
flame ionization detector; must have a
heated sampling line maintained at a
temperature of 150 degrees Celsius or
higher at all times; and must be
calibrated at least once every 24-hour
operating period using propane. More
discussion on the requirement to
monitor THC continuously is presented
in other parts of today's preamble.
The second management practice
requires installation of an instrument
that measures and records the oxygen
concentration in the sewage sludge
incinerator stack exit gas continuously.
Such an instrument must be calibrated,
operated, and maintained for each
sewage sludge incinerator. This
management practice is needed to
obtain the information to correct the
THC concentration to seven percent
oxygen.
The third management practice
requires the installation of an
instrument that measures and records
information used to determine the
moisture content in the sewage sludge
incinerator stack exit gas continuously.
Such an instrument must be calibrated,
and maintained for each sewage sludge
incinerator. Information obtained
through this management practice is
used to correct the measured THC
concentration for zero percent moisture.
The fourth management practice
requires the installation of an
instrument that measures and records
combustion temperatures continuously.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9357
Such an instrument must be calibrated,
operated, and maintained for each
sewage sludge incinerator, as specified
by the permitting authority. This
management practice is needed to
obtain information about combustion
temperatures and to ensure that the
sewage sludge incinerator is operated in
a manner similar to how it was operated
during the performance test to
determine pollutant control efficiencies.
The fifth management practice
indicates that the permitting authority
will specify the maximum combustion
temperature for the sewage sludge
incinerator. That temperature will be
based on information obtained during
the performance test of the incinerator
to determine pollutant control
efficiencies. This management practice
ensures that the maximum combustion
temperature does not exceed the
maximum combustion temperature
during the performance test.
The sixth management practice
indicates that the permitting authority
will specify the values for the operating
parameters for the sewage sludge
incinerator air pollution control device.
Those values also will be based on
information obtained during the
performance test to determine pollutant
control efficiencies. The purpose of this
management practice is to ensure that
the air pollution control device is
operated in a manner similar to how it
was operated during the performance
test.
The final regulation provides that
firing of sewage sludge in a sewage
sludge incinerator is prohibited if it is
likely to adversely affect a threatened or
endangered species listed under section
4 of the Endangered Species Act or its
designated critical habitat (503.45(g)).
EPA will develop guidance to carry out
this provision consistent with the
Endangered Species Act.
Frequency of Monitoring (Section
503.46)
This section contains the frequency of
monitoring requirement that apply
when sewage sludge is fired in a sewage
sludge incinerator. This includes the
frequency of monitoring for pollutant
concentrations, total hydrocarbons
concentration and oxygen concentration
in the exit gas from a sewage sludge
incinerator stack, information used to
calculate the moisture content in the
exit gas, combustion temperatures, and
the air pollution control device
operating parameters.
The frequency of monitoring for
pollutant concentrations is based on the
amount of sewage sludge fired in a
sewage sludge incinerator during a 365
day period. The larger the amount fired,
the more frequently the sewage sludge
fed to the sewage sludge incinerator
must be monitored for pollutant
concentrations. A discussion of the
amounts of sewage sludge in the
frequency of monitoring table is
presented in the section in today's
preamble on land application and in the
technical support document for the part
503 incineration requirements.
Part 503 also requires that the THC
concentration and oxygen concentration
in the exit gas from the sewage sludge
incinerator stack, information used to
calculate the moisture content in the
exit gas, and combustion temperatures
be monitored continuously. In addition,
the final regulation indicates that the
frequency of monitoring for the air
pollution control device parameters
shall be determined by the permitting
authority.
The final regulation allows the
permitting authority to reduce the
frequency of monitoring for pollutant
concentrations after two years of
monitoring at the required frequency, as
long as the frequency of monitoring is
at least once per year when sewage
sludge is fired in a sewage sludge
incinerator. In deciding whether to
reduce the frequency of monitoring, the
permitting authority should consider,
among other things, the variability of
the pollutant concentrations and the
magnitude of the pollutant
concentrations. The Agency concluded
that two years is an adequate period to
collect data to make the judgment about
reducing the frequency of monitoring.
Note that only the permitting authority
can reduce the frequency of monitoring.
Recordkeeping (Section 503.47)
The final part 503 regulation requires
the person who fires sewage sludge in
a sewage sludge incinerator to develop
the information specified in this section
and to retain the information for five
years. The information that has to be
developed is information needed to
calculate pollutant limits for lead,
arsenic, cadmium, chromium, and
nickel; information needed to ensure the
limits for those pollutants are met; and
information needed to ensure the
standards for beryllium and mercury are
met. In addition, records of the total
hydrocarbons and oxygen
concentrations in the exit gas from a
sewage sludge incinerator, the
information needed to calculate
moisture content of the exit gas, and
information on combustion
temperatures and air pollution control
device operating parameters must be
kept.
Reporting (Section 503.48)
Class I sludge management facilities,
POTWs with a design flow rate equal to
or greater than one million gallons per
day, and POTWs that serve 10,000
people or more must report the
information in 503.47(b) through
503.47(h) to the permitting authority
once per 365 day period. The section in
today's preamble on land application
explains the reasons for requiring Class
I sludge management facilities, POTWs
with a design flow rate of one MGD or
greater, and POTWs that serve 10,000
people or more to report information.
Part XII: Implementation of 40 CFR
Part 503
Clean Water Act
The 1987 amendments to the Clean
Water Act included significant changes
to section 405 regarding the
implementation of standards for the use
or disposal of sewage sludge. Prior to
the 1987 amendments, the CWA
required that EPA develop standards for
the use and disposal of sewage sludge
applicable to POTWs, but it did not
specify how the standards were to be
implemented, whether through permits
and, if so, under what authority.
Traditionally, National Pollutant
Discharge Elimination System (NPDES)
jurisdiction under the CWA arises when
a point source discharges pollutants to
navigable waters. Thus questions arose
about the applicability of NPDES
permits to regulate sewage sludge
disposal that did not involve discharges
to navigable waters. Likewise, other
permits either are medium-specific (e.g.,
permits issued under the Clean Air Act)
or regulate particular substances or
methods of disposal (e.g., Subtitle D of
the Resource Conservation and
Recovery Act (RCRA)); therefore, they
also were ill-equipped to regulate
comprehensively the use and disposal
of sewage sludge across all media.
The 1987 CWA amendments establish
a program to protect public health and
the environment from the reasonably
anticipated adverse effects of pollutants
in sewage sludge. In addition to
requiring development of standards that
establish pollutant limits and
management practices for each use and
disposal method, the CWA establishes
requirements for inclusion of these
standards in specified permits issued to
treatment works treating domestic
sewage. Thus, section 405(f) requires
inclusion of conditions to implement
the sewage sludge standards in NPDES
permits, unless these conditions are
included in a permit issued either under
one of the listed Federal programs or by
an approved State sewage sludge
-------
9358 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
program. Section 405(f](l), as amended,
provides:
Through Section 402 Permits.—Any permit
Issued undor Section 402 of this Act to a
publicly owned treatment works or any other
treatment works treating domestic sewage
shall include requirements for the use and
disposal of sludge that implement the
regulations established pursuant to
subsection (d) of this section, unless such
requirements have boon included in a permit
Issued under the appropriate provisions of
subWlo C of the Solid Waste Disposal Act,
part C of tho Safe Drinking Water Act, the
Marino Protection, Research, and Sanctuaries
Act of 1972, or tho Clean Air Act, or under
Slate permit programs approved by the
Administrator, whore the Administrator
determines that such programs assure
compliance with any applicable
requirements of this section* * *
Thus the CWA requires EPA to
implement the standards through
NPDES permits unless the standards are
not included in a Clean Air Act permit,
a RCRA subtitle C permit, a Marine
Protection, Sanctuaries, and Research
Act permit, an Underground Injection
Control permit under the Safe Drinking
Water Act, or an approved State
program permit. It is clear that permit
coverage among the programs is to be
complementary, not duplicative.
However, it also is clear from the
statutory scheme that Congress
contemplated comprehensive coverage
of publicly owned treatment works and
other treatment works treating domestic
sewage through the permit program. No
facilities are to go unpermitted merely
because they fall outside the traditional
jurisdiction of medium-specific
programs. Thus, if a POTW or other
treatment works treating domestic
sewage does not have an NPDES permit,
or any of the other permits listed in
section 405(f)(l) that implements the
sewage sludge standards, the CWA
provides that EPA may issue a permit
solely to implement the sewage sludge
standards, commonly referred to as a
"sludge-only permit." (See CWA section
405(f)(2).)
Another important provision of
section 405(f)(l) allows a State to issue
permits to implement the technical
standards where the State permit
program has been approved by the
Administrator. The Administrator may
approve a State program upon
determining that the State program will
assure compliance with the
requirements of section 405. EPA
interpreted the CWA to provide for
optional, not mandatory, State
programs, even if the State already has
an approved NPDES program. In the
absence of an approved State program,
tho appropriate EPA Regional Office
will be the permit issuance authority for
that State.
In addition, section 405(e) of the
statute is clear that the obligation to
comply with sewage sludge standards is
independent of any permit or permit
conditions.
The determination of the manner of
disposal or use of sludge is a local
determination except that it shall be
unlawful for any person to dispose of sludge
from a publicly owned treatment works or
any other treatment works treating domestic
sewage for any use for which regulations
have been established pursuant to [section
405(d)], except in accordance with such
regulations.
Sewage Sludge Management Program
Regulations
On May 2,1989, EPA promulgated
regulations outlining the criteria for
approving State sludge permit programs
and establishing permitting
requirements for sewage sludge
management (54 FR18726). These
regulations implement two CWA
requirements: first, that permits issued
to POTWs and other treatment works
treating domestic sewage contain the
sewage sludge standards; and second,
the requirement that EPA promulgate
procedures for the approval of State
programs. The purpose of the State
program and permitting rules is to
provide the implementation framework
for the sewage sludge technical
standards by: (1) Providing permit
conditions to incorporate the standards
into permits, as well as additional
requirements to track compliance with
the standards; and (2) setting approval
requirements for State sewage sludge
programs so that States can implement
the section 405 requirements.
The May 2,1989, regulations
contained three principal sections. First,
the rules revised the existing NPDES
permitting regulations at 40 CFR parts
122 and 124 to include sewage sludge
conditions in NPDES permits and
established these regulations as the
basis for issuing sludge-only permits.
Second, the rules contained revisions to
40 CFR part 123 for States with NPDES
authority that wish to modify their
existing NPDES programs to include the
regulation of sewage sludge. Third, the
May 2,1989, rules contained a separate
part, part 501, establishing procedures
for approving State sludge management
programs that are not part of a State's
NPDES program. In addition, part 501
specifies the requirements for State non-
NPDES sewage sludge programs. These
regulations reflect the intention of CWA
section 405(f) that the sewage sludge
standards may be included in any of a
number of permits under different
programs, so long as they are addressed
in a permit issued to a POTW or other
treatment works treating domestic
sewage. When EPA is the permitting
authority (i.e., where the State has not
sought and obtained approval of its
sewage sludge permitting program), the
sewage sludge requirements will be
implemented primarily through NPDES
permits, unless the requirements are
contained in one of the other listed
Federal permits.
Requirements Prior to Promulgation of
the Technical Standards
The CWA also requires that, prior to
promulgation of the technical standards,
NPDES permits issued to POTWs are to
contain sewage sludge conditions.
Moreover, the Administrator is
authorized to take other appropriate
measures to protect public health and
the environment from the adverse
effects of sewage sludge (see CWA
section 405(d)(4)). In response to this
call for controls before promulgation of
the technical standards, EPA developed
an interim strategy for sewage sludge
permitting, in a document entitled
"Strategy for Interim Implementation of
Sludge Requirements in Permits Issued
to POTWs" (September 1989).
Now that the part 503 standards are
promulgated in today's action, EPA will
regulate the use and disposal of sewage
sludge by those standards. The interim
program, however, will continue to
apply to those facilities, pollutants, and
use and disposal methods not covered
by today's standards. EPA retains
authority to impose permit limits
developed on a case-by-case basis or to
take other appropriate action necessary
to protect public health and the
environment regarding pollutants and
management practices not regulated by
the part 503 standards, and to impose
more stringent limits and requirements
where the part 503 standards are not
sufficiently protective at a particular
site.
Relationship Between the Sewage
Sludge Program Regulations and
Today's Standards for Sewage Sludge
Use or Disposal
The standards for sewage sludge use
or disposal promulgated today apply to
various final use or disposal practices
that may be carried out by numerous
parties. Before the 1987 CWA
amendments, the standards applied
only to POTWs. Recognizing that parties
other than POTWs are likely to use or
dispose of sewage sludge, Congress
amended section 405 (e) to make the
standards applicable toJany person who
uses or disposes of sewage sludge. Thus,
the Clean Water Act provides that
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9359
POTWs and other treatment works
treating domestic sewage, as well as
other users and disposers, are subject to
the standards. Moreover, section 405(e)
makes these standards independently
enforceable even if conditions to
implement the standards have not been
included in a permit as provided in
section 405(f).
EPA's program for implementing and
enforcing today's standards follows the
two-pronged approach established by
the Clean Water Act. First, the standards
are directly enforceable against any user
or disposer of sewage sludge. POTWs
and other generators of sewage sludge
are users and disposers of sewage sludge
even if final use or disposal is provided
by some other party. Under the existing
regulations and in accordance with the
Interim Permitting Strategy, permits
reissued to POTWs after the 1987
amendments should include conditions
specifying that POTWs are expected to
comply with the part 503 standards by
the statutory deadlines even if the
permits themselves are not modified to
incorporate those standards. EPA will
enforce the final part 503 standards in
accordance with the Agency's existing
Enforcement Management System
(EMS). Second, the standards will be
implemented through permits issued to
POTWs and other treatment works
treating domestic sewage (discussed
more fully in the following section on
"who must apply for a permit").
Initially, EPA will rely strongly on the
direct enforceability of the standards.
Over the long term, however, EPA
intends that permits will become the
primary mechanism for implementing
the standards for POTWs and other
treatment works treating domestic
sewage.
The following discussion addresses
several key issues related to
implementation of the standards using
the programmatic framework
established by the permitting
requirements and State program rules
promulgated on May 2,1989: (1) Who
must apply for a permit, (2) permit
application requirements, (3) permitting
priorities, (4) requirements in the
absence of a permit, (5) who issues the
permit and the role of existing State
programs, and (6) EPA's plans for
outreach and training to foster
implementation of the standards. Many
of the permitting issues, as well as
others related to the national sewage
sludge program, are discussed in more
detail in the May 2,1989, Federal
Register notice (54 FR 18716).
Who Must Apply for a Permit
The CWA requires today's technical
standards to be included in permits
issued to the key actors involved in
generating, treating, and disposing of
sewage sludge. Section 405(f)(l) defines
the permitting universe to include
POTWs and other treatment works
treating domestic sewage, including
facilities that are not required to obtain
NPDES permits pursuant to section 402
of the CWA (section 405(f)(2)).
"Treatment works treating domestic
sewage" is defined at 40 CFR 122.2 to
mean:
A POTW or any other sewage sludge or
waste water treatment devices or systems,
regardless of ownership (including Federal
facilities) used in the storage, treatment,
recycling and reclamation of municipal or
domestic sewage, including land dedicated
for the disposal of sewage sludge. This
definition does not include septic tanks or
similar devices. For purposes of this
definition, "domestic sewage" includes
waste and waste water from humans or
household operation that are discharged to or
otherwise enter a treatment works. In States
where there is no approved State sludge
management program under section 405(f) of
the CWA, the Regional Administrator may
designate any person subject to the standards
for sewage sludge use and disposal in 40 CFR
part 503 as a "treatment works treating
domestic sewage," where he or she finds that
thers is a potential for adverse effects on
public health and the environment from poor
sludge quality or poor sludge handling, use
or disposal practices, or where he or she
finds that such designation is necessary to
ensure that such person is in compliance
with 40 CFR part 503.
As explained in the preamble to the
sludge permitting regulations, the
purpose of this definition is to capture
all those facilities that "generate sewage
sludge or otherwise effectively control
the quality of sewage sludge or the
manner in which it is disposed (and
hence its effect on the environment.)"
54 FR 18725-6 (May 2,1989). Thus, all
POTWs must have permits that
implement applicable technical
standards. Generally, the permit issued
to the POTW must include standards
applicable to sewage sludge quality as
well as the other permit conditions
required by 40 CFR part 122 (e.g.,
standard conditions and compliance
monitoring requirements). In addition,
the permit may include conditions
related to any aspect of sewage sludge
management developed on a case-by-
case basis where the permitting
authority determines that such
conditions are necessary to protect
public health and the environment. For
example, today's rule does not establish
standards for temporary storage of
sewage sludge. The permitting authority
may develop permit requirements to
address potential problems at temporary
storage facilities such as contamination
of surface water or ground water or
unrestricted public access to temporary
storage locations.
The permit may also include
conditions establishing a POTW's
responsibilities when it sends its sewage
sludge to other facilities for final use or
disposal. As a general rule, a permit
issued to a POTW that sends its sewage
sludge to another treatment works
treating domestic sewage should specify
the conditions under which that POTW
would be relieved of its responsibility
for use or disposal of its sewage sludge
in compliance with section 405 (d)
standards. Generally, a POTW retains
responsibility for use and disposal of its
sewage sludge (i.e., compliance with
part 503 standards applicable to its use
or disposal practices) unless it transfers
its sewage sludge to another treatment
works treating domestic sewage. For
example, a permit issued to a POTW
that sends its sewage sludge to an
incinerator owned by another
municipality would not necessarily
include all standards applicable to
incineration. The permit for the
generating POTW would generally have
standard conditions, while the permit
issued to the incinerator would contain
standard conditions and other specific
conditions relating to the operation of
the incinerator and the quality of
sewage sludge going into the
incinerator.
The scheme contemplates that
facilities other than POTWs may also be
required to apply for permits. Treatment
works treating domestic sewage, as
noted above, include facilities dedicated
to the disposal of sewage sludge (i.e.,
surface disposal sites and incinerators).
In addition, certain facilities that handle
sewage sludge may be required to apply
for a permit, particularly where they
alter the nature of the sewage sludge
before ultimate use or disposal. EPA
considers that the sewage sludge has
undergone a change in quality if,
through processes such as stabilization,
composting, digestion, or heat
treatment, a change has occurred in
pollutant concentrations, pathogen
levels, or vector attraction properties of
the sewage sludge (on a dry weight
basis) sufficient to change its regulatory
status under part 503. A sewage sludge
also changes in quality if it is blended
permanently with bulking agents (such
as sawdust or wood chips) or with
sewage sludge from another treatment
works (as a material derived from
sewage sludge, a sewage sludge product
remains subject to the definition of
sewage sludge under section 503.9).
EPA does not consider dewatering, of
itself, to constitute a change in sludge
quality. Dewatering increases the solids
content of sewage sludge without
-------
9360 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
necessarily changing its dry-weight
pollutant concentrations, pathogen
levels, or vector attraction properties; in
addition, because sewage sludge
monitoring information is reported on a
dry weight basis, the solids content of
the sewage sludge is irrelevant to its
quality under part 503. EPA also does
not consider the placement of sewage
sludge in a bag or other container for
sale or giveaway to constitute treatment
or a change in sludge quality, since the
sludge has not been modified with
respect to pollutant concentrations,
pathogen levels, or vector attraction
properties. Thus a person who simply
dowators the sewage sludge, or who
places the sewage sludge in a bag or
similar enclosure for sale or
distribution, would not be a treatment
works treating domestic sewage.
If the treatment works generating the
sewage sludge transfers sewage sludge
to a person who changes the quality of
the sewage sludge, the entity changing
the quality is a treatment works treating
domestic sewage. That entity is not only
subject to part 503 standards but is also
required to apply for a permit. If,
however, the treatment works
generating the sewage sludge provides
sewage sludge to a person who does not
change the quality, the generating
treatment works retains the
responsibility for the ultimate use or
disposal of the sludge and must ensure
that the part 503 requirements are met.
Generally, as noted above, facilities
other than POTWs that do not change
the quality of sewage sludge would not
be required to apply for permits. Among
such facilities or operations are contract
sludge haulers or land appliers.
However, as previously explained, EPA
retains the authority under section
405(d)(4) of the CWA to take such action
as it determines is appropriate to protect
public health and the environment from
adverse effects from the pollutants in
sewage sludge. EPA's current
regulations at 40 CFR I22.1(b)(4)
provide that the Regional Administrator
may designate any person subject to the
standards for sewage sludge use and
disposal as a treatment works treating
domestic sewage where necessary to
protect public health and the
environment from the adverse effects of
sewage sludge or to ensure compliance
with the sewage sludge technical
standards. Exorcising this authority, in
special circumstances, EPA may
conclude that protection of public
health and the environment requires a
facility or operation to apply for a
permit that otherwise would not need
one.
Tho discussion below elaborates upon
tlio foregoing and addresses who must
apply for a permit and how other users
and disposers might be regulated by use
and disposal practice.
Land Application
Land application, under § 503.11 of
today's rule, essentially refers to the
beneficial use of sewage sludge through
placement in or on the soil, in a manner
that utilizes the fertilizing and soil
conditioning properties of the sewage
sludge. The definition of land
application covers a number of
scenarios. Sewage sludge may be
applied to the land in bulk form,
directly by the treatment works or by a
commercial enterprise. Land application
of bulk sewage sludge may take place on
land owned by the treatment works or
on privately-held land. Sewage sludge
may also be packaged and distributed,
in some cases after further processing,
for sale or give-away to the general
public.
Land application may involve any or
all of the following parties: The
treatment works generating the sewage
sludge (or other person who prepares
the sewage sludge for application to the
land), a distributor of the sewage sludge,
a person who applies the sewage sludge
to the land, and the owner or
leaseholder of the land to which the
sewage sludge is applied. In the
simplest case, where the treatment
works (or a commercial land applier
that does not change the quality of the
sewage sludge) applies the sewage
sludge to land owned by the treatment
works, the treatment works retains
control over the entire process of sewage
sludge generation, treatment, and
application to the land. In other cases,
the treatment works provides the
sewage sludge to another party for
further treatment (such as composting)
or blending with sewage sludges from
other treatment works and by so doing
the treatment works at some point
effectively relinquishes control over the
quality of the sludge.
Subpart B of today's regulation
applies to a person who applies sewage
sludge to the land, to a person who
prepares sewage sludge for application
to the land, to the sewage sludge
applied to the land, and to the land on
which sewage sludge is applied. Any
person who generates sewage sludge or
who changes the quality of sewage
sludge and controls the ultimate use or
disposal of sewage sludge is a treatment
works treating domestic sewage and
must apply for a permit containing
sewage sludge conditions. Typically,
owners or occupants of land on which
sewage sludge is applied are not
considered treatment works treating
domestic sewage and need not apply for
a permit. They would, however, be
expected to comply with any standards
that apply to management of the site
after the sewage sludge is applied (e.g.,
any access restrictions associated with
sewage sludge meeting Class B pathogen
requirements).
If the treatment works is the party that
applies sewage sludge to the land, the
treatment works will be issued a permit
that spells out the conditions for land
application contained in today's rule. If
the treatment works uses a commercial
sewage sludge applier that does not
change the quality of the sewage sludge
for land application, the treatment
works will still be held accountable
under today's rule and through its
permit for the commercial applier's
compliance with the part 503 standards,
since the Agency considers that the
treatment works still retains control
over the quality of the sewage sludge. In
this case, as the generator of sewage
sludge, the treatment works cannot limit
its responsibility for the use and
disposal of the sewage sludge in
compliance with the standards merely
by transferring the sludge to a
commercial applier. The applier would,
however, also be governed directly by
the part 503 standards. If the treatment
works applies its sewage sludge to the
land in another jurisdiction, it may also
need to apply for a State or local permit
in that jurisdiction (to enable that
jurisdiction to impose compliance
monitoring and facilitate any necessary
enforcement actions). On the other
hand, if the treatment works transfers
the sewage sludge to another treatment
works treating domestic sewage (such as
a commercial treatment facility,
fertilizer manufacturer, or disposal
service), that second treatment works
treating domestic sewage would be
required to apply for a permit that
essentially picks up control where the
generating treatment works' permit
leaves off.
Subpart B of today's rule includes
general requirements, pollutant limits,
management practices, pathogen
requirements, and vector attraction
requirements. As described elsewhere in
today's rulemaking, in certain cases a
sewage sludge or sewage sludge product
that meets certain minimum quality
requirements is not required to meet
some or all of the controls under part
503. The Agency believes that if sewage
sludge (or material derived from sewage
sludge) meets these requirements prior
to land application, no further controls
are needed on the sewage sludge or on
the land where the sewage sludge is
applied in order to protect public health
and the environment from reasonably
anticipated adverse effects of pollutants
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9361
in the sewage sludge. The rationale for
not applying the general requirements
and management practices is that
sewage sludge that meets the three
quality requirements has a
comparatively higher value. Because of
this, the sludge most likely will not be
applied to the land inappropriately (i.e.,
"wasted"). In addition, the Agency does
not expect over application to occur
because it could reduce crop yield,
which is counter to the main reason to
apply sewage sludge to the land. When
the sewage sludge meets the three
quality requirements, it is a fertilizer
material and should be regulated
similarly to other fertilizers.
Under § 503.10 of today's rule, the
general requirements of § 503.12 and the
management practices of § 503.14 do not
apply to a bulk or bagged sewage sludge
if the sewage sludge meets the pollutant
concentrations in § 503.13(b)(2), the
Class A pathogen requirements in
§ 503.32(b), and one of the vector
attraction requirements in 503.33(b)(l)-
(8). The general requirements and
management practices do not apply to a
material derived from bulk or bagged
sewage sludge if the material meets the
minimum concentration, pathogen, and
vector attraction requirements. All
Subpart B standards, including
monitoring, recordkeeping, and
reporting requirements' are inapplicable
to material derived from bulk or bagged
sewage sludge, if the sewage sludge
used to produce that material meets the
minimum concentration, pathogen, and
vector attraction requirements described
above. The treatment works generating
the sewage sludge from which the
material is derived remains responsible
for any monitoring, recordkeeping, and
reporting requirements, however.
After it is generated, sewage sludge
generally will be land applied according
to one of the following three scenarios:
(1) The treatment works (or a
commercial applier that does not change
the quality of the sewage sludge) applies
the sewage sludge to the land (i.e.,
under the wording of today's rule, the
"person who prepares" is also the
"person who applies"); (2) the treatment
works provides the sewage sludge to
another treatment works treating
domestic sewage that further changes
sludge quality and assumes
responsibility for ultimate land
application (i.e., the "person who
prepares" provides the sewage sludge to
another "person who prepares"); or (3)
the treatment works demonstrates that
the sewage sludge meets certain
minimum quality requirements and
that, as described above, no further
sewage sludge management
requirements (except for certain
monitoring, recordkeeping and
reporting requirements) apply.
An explanation for each scenario
follows:
(1) If the treatment works applies its
sewage sludge to the land (or sends it to
a commercial applier that does not
change the quality of the sludge), the
treatment works retains direct control
over the quality of the sewage sludge
and is responsible for ensuring that the
part 503 standards are met. In its permit
application, the treatment works must
announce its intent to apply its sewage
sludge to the land either directly or
through the use of a commercial applier.
In the permit application, the treatment
works must either identify all land
application sites in advance, or submit
a copy of its land application plan,
which includes the geographical area
covered, the site selection criteria, site
management practices, and a provision
for public notice (including at a
minimum notice to the permitting
authority and adjacent landholders)
(§501.15(a)(2)(ix)).
The permit issued to the treatment
works will contain the part 503
requirements that address the land
application practices described in the
permit application. EPA has determined
that, when Congress amended section
405 (e) to extend the obligation to
comply with the sludge standards to
each person using or disposing of
sewage sludge, Congress did not intend
to limit or transfer the responsibility of
the generating POTW for ensuring
compliance with the standards except
insofar as the generating POTW sends
the sewage sludge to another treatment
works treating domestic sewage. In
other words, a treatment works
generating sewage sludge retains its
duty to comply with the sewage sludge
use and disposal standards except
where it transfers its sludge to another
treatment works treating domestic
sewage that is itself subject to
permitting requirements under section
405(f)oftheCWA.
The treatment works generating the
sewage sludge must apply for a permit
and must identify, in the permit
application, the person(s) who will
apply sewage sludge to the land. In its
application, the treatment works
generating the sewage sludge must also
identify the land application sites or
submit a land application plan. EPA
expects that although the treatment
works generating the sewage sludge
does not actually apply the sewage
sludge to the land, the treatment works
generating the sewage sludge will exert
sufficient control over the land applier
to enable the applier to comply with the
part 503 standards. For this reason,
§ 503.12 requires the treatment works to
provide the applier with the information
necessary to comply with the standards.
Since under this scenario the land
applier does not treat the sewage sludge
or otherwise change sludge quality, the
land applier is not a treatment works
treating domestic sewage and is not
required to apply for a permit. In this
case the part 503 standards apply
directly to the land applier. The permit
issued to the treatment works generating
the sewage sludge must contain
sufficient controls to ensure that the
treatment works informs the land
applier of what requirements must be
met, and that the treatment works is
held responsible for compliance with
part 503 by the land applier.
Certain part 503 requirements apply
to the treatment works generating the
sewage sludge, and certain requirements
apply to the land applier. Generally,
they can be summarized as follows:
« Under § 503.12, the generating
treatment works must provide both the
land applier and the site owner with the
information necessary to comply with
part 503.
• The generating treatment works
must ensure that the sewage sludge
meets the pollutant limits in § 503.13.
• The sewage sludge must be applied
to the land in accordance with the
management practices in § 503.14. The
treatment works generating the sewage
sludge will be responsible for informing
the land applier of applicable
management practices, and the land
applier will be responsible for
compliance with those management
practices.
• The generating treatment works is
responsible for providing all necessary
treatment to meet the pathogen and
vector attraction requirements in
§ 503.15. The land applier and site
owner will together be responsible for
carrying out any necessary site access
restrictions.
• The generating treatment works
must monitor the sewage sludge
according to the requirements in
§503.16.
• The generating treatment works
must keep records as required in
§503.17.
• The generating treatment works
must report to the permitting authority
as required in § 503.18 if it is a Class I
sludge management facility or if it is
required to do so in its permit.
(Conceivably, a land applier could be
designated by the permitting authority
as Class I or otherwise subject to
reporting.)
(2) Under the second scenario, the
sewage sludge is not applied to the land
by the treatment works generating the
-------
9362 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sowago sludge, but it is provided to a
person who provides further treatment
or otherwise changes the quality of the
sowago sludge (i.e., another "person
who prepares"). The person who
changes the quality of the sewage sludge
may apply it to the land in bulk form,
place it in a bag or similar enclosure for
sale or distribution to the public, or
provide it to another facility for further
distribution and marketing.
Both the treatment works generating
the sewage sludge and the person who
changes the sewage sludge quality must
apply for a permit. In its permit
application, the generating treatment
works must identify the person who
will change the quality of the sewage
sludge; under § 503.12, it must provide
that person with the information
necessary to comply with part 503. The
person who changes sewage sludge
quality must comply with the part 503
requirements in its permit (or, pending
permit issuance, with part 503 directly).
(3) Certain part 503 requirements are
inapplicable to the treatment works
generating the sewage sludge if the
sewage sludge meets certain minimum
criteria regarding pollutant
concentrations, pathogen levels, and
vector attraction properties. If the
sewage sludge (or the material derived
from sludge) meets the pollutant
concentrations in §503.13(b)(3), the
Class A pathogen reduction
requirements in § 503.32(a), and one of
the vector attraction requirements of
§503.33 (b) (1H8), the treatment works
generating the sewage sludge not
required to meet the general
requirements of § 503.12 and the
management practices of § 503.14.
Furthermore, if a material is derived
from a sewage sludge that meets the
pollutant concentrations in
§503.13(b)(3), the Class A pathogen
reduction requirements in § 503.32(a),
and one of the vector attraction
requirements of §503.33 (b) (l)-(8), the
material is not required to meet the
subpart B requirements, including
monitoring, recordkeeping, and
reporting requirements.
Surface Disposal
Surface disposal, under today's
regulation, is the placement of sewage
sludge on an area of land dedicated to
the disposal of sewage sludge and
containing one or more active "sewage
sludge units." A surface disposal site is,
by definition, a treatment works treating
domestic sewage. Subpart C of today's
rulemaking applies to any person who
prepares sewage sludge for placement
on a surface disposal site, to the owner/
operator of a surface disposal site, to the
sowago sludge placed on a surface
disposal site, and to a surface disposal
site.
As a treatment works treating
domestic sewage, a surface disposal site
is subject to permitting requirements
under part 122,124 or 501. If a surface
disposal site is owned or operated by
the treatment works generating the
sewage sludge (i.e., the "person who
prepares"), the part 503 requirements
for the disposal site will be contained in
the permit issued to the generating
treatment works. If, however, the
surface disposal site is owned or
operated by another party, both parties
must apply for permits containing
applicable part 503 requirements.
Applicable requirements are in subpart
C of part 503 and consist of general
requirements (§ 503.22); pollutant limits
(§ 503.23); management practices
(§ 503.24); pathogen and vector
attraction requirements (§ 503.25); and
monitoring, recordkeeping* and
reporting requirements (§§ 503.26-?- ;
503.28).
Incineration
Subpart E of today's regulation
applies to any person who fires sewage
sludge in a sewage sludge incinerator, to
sewage sludge fired in a sewage sludge
incinerator, and to a sewage sludge
incinerator. Subpart E includes general
requirements (§ 503*42); pollutant limits
(§ 503.43); operational standards ,
(§ 503.44); management practices
(§ 503.45); and monitoring,
recordkeeping, and reporting
requirements (§ 503.46 through
§ 503.48). Under § 503.43, site-specific
variables (incinerator type, dispersion
factor, control efficiency, feed rate, stack
height) must be used to calculate
allowable daily concentrations of
arsenic, cadmium, chromium, lead, and
nickel in the sewage sludge fed to the
incinerator. '
A sewage sludge incinerator is
considered to be a treatment works
treating domestic sewage under 40 CFR
122.2 and therefore must obtain a
permit. If, as is mostly the case, a
sewage sludge incinerator is operated by
the treatment works generating the
sewage sludge, the permit issued to the
generating treatment works will contain
the part 503 requirements applicable to
its sewage sludge incinerator. In those
instances where a treatment works
generating sewage sludge sends its
sewage sludge to another sewage sludge
incinerator, the permit issued to the
generating treatment works would
generally contain standard conditions.
The sewage sludge incinerator's permit,
meanwhile, would include the sewage
sludge pollutant limits, emission limits,
operational standards, and management
practices required by the part 503
incinerator standards.
Septage Haulers
Domestic septage is considered
sewage sludge under today's rule;
therefore, users and disposers of
domestic septage must comply with the
standards applicable to their use or
disposal practices. However, EPA
generally does not expect to issue
permits to septage haulers because they
are not considered to be treatment
works treating domestic sewage (unless
specifically designated by the Regional
Administrator). (54 FR 18726, May 2,
1989). Instead, EPA will rely on the
direct enforceability of today's rule to
implement the standards with respect to
septage haulers.
Septage haulers will be required to
keep records of basic information about
their use and disposal practices. (Note:
Septage taken to a POTW for treatment
is not considered use or disposal and,
therefore, is not covered by today's
standards.) The person applying the
domestic septage to the land must
comply with requirements for annual
application rate (§503.13(c)), pathogen
and vector attraction (§ 503.15 (b) and
(d)), monitoring (§ 503.16(b)), and
recordkeeping (§503.17(b)).
(Alternately, the person applying the
domestic septage may comply with the
subpart B requirements for sewage
sludge unless specifically indicated
otherwise. Because the sewage sludge
standards are more stringent, EPA does
not expect many septage haulers to
select them.)
Surface disposal of domestic septage
is subject to the vector attraction
requirements of subpart D. Under
§ 503.26, each container of domestic
septage placed on a sewage sludge unit
shall be monitored for compliance with
the vector attraction requirement of
§ 503.33(b)(12), if the vector attraction
requirement in § 503.33(b)(12) is met
when domestic septage is placed on an
active sewage sludge unit.
Permit Application Requirements
Currently, under §§ 122.22(c)(2)(i) and
501.15(d)(l)(ii)(A) of the sewage sludge
permit program regulations, any POTW
or other treatment works treating
domestic sewage with an existing
NPDES permit must submit sewage
sludge permit application information
when its next application for NPDES
permit renewal is due, or within 120
days of promulgation of an applicable
part 503 standard for sewage sludge use
or disposal, whichever comes first. If a
treatment works treating domestic
sewage is not subject to the NPDES
permitting program (i.e., it is a "sludge
-------
Federal Register /.Vol. 58, No. 32 /Friday, February 19, 1993 / Rules and Regulations 9363
only facility"), it is required under
§§ 122.21(c)(2)(ii) and 501.15(d)(l)(ii)(B)
to submit permit application
information within 120 days of
promulgation of an applicable part 50.3
standard or upon request of the Director.
If a treatment works treating domestic
sewage commences operation after
promulgation of an applicable part 503
standard, it is required under
§§ 122.21(c)(2)(iii) and
501.15(d)(l)(ii)(C) to submit a permit
application at least 180 days prior to the
date proposed for commencing
operations.
EPA estimates that approximately
16,000 POTWs are in operation
nationwide and that between 3,000 and
5,000 other facilities also meet the
definition of treatment works treating
domestic sewage because they exert
control over the quality or disposal of
sewage sludge. Under existing
regulations, therefore, up to 20,000
POTWS and other treatment works
treating domestic sewage would be
expected to submit sewage sludge
permit application information by June
21,1993.
On May 27,1992, EPA proposed a
phased approach to the submittal of
sewage sludge permit applications,
which would reduce the number of
applications received during the period
immediately following promulgation of
the part 503 standards. (57 FR 22197).
EPA proposed this approach to manage
permit applications more efficiently and
to prioritize permitting activities among
different types of facilities and sewage
sludge use or disposal activities. EPA
expects to promulgate the revised
permit application requirements after
promulgation of these standards.
Under the phased approach, as
proposed in EPA's May 27,1992 notice,
the Agency would only require sewage
sludge permit applications during the
initial period following promulgation of
part 503 from treatment works treating
domestic sewage that are expected to
have site-specific pollutant limits in
their permits. Certain treatment works
treating domestic sewage are required to
have site-specific permit limits. Other
treatment works treating domestic
sewage may request site-specific permit
limits under certain circumstances, as
discussed below.
Site-specific permit limits are
required for sewage sludge that is fired
in a sewage sludge incinerator or placed
on certain types of surface disposal
sites. Applicants intending to incinerate
sewage sludge in sewage sludge
incinerators are required, under § 503.43
of today's rule, to use site-specific
variables (incinerator type, dispersion
factor, control efficiency, feed rate, stack
height) to calculate allowable daily
concentrations of arsenic, cadmium,
chromium, lead, and nickel in the
sewage sludge fed to the incinerator.
Pollutant limits for surface disposal
sites may be calculated on a site-specific
basis where the site-specific parameters
at the site are different from die national
model (§ 503.23(b)). Under the proposed
application deadline rule, requests for
site-specific limits will be considered
beyond the first round of permit
applications only for good cause. Good
cause includes instances where an
applicant does not have information
when the part 503 standards are
promulgated to indicate that site-
specific pollutant limits will be
necessary (e.g., it- changes use or
disposal practices). -
For treatment works treating domestic
sewage that currently have NPDES
permits and will not need site-specific
pollutant limits, the sewage sludge
information would be submitted when
their applications for permit renewal are
due. Sludge-only facilities (i.e., those
without existing NPDES 'permits) would
submit a subset of application :
information within one year after
promulgation of an applicable part 503
use or disposal standard. Based on this
information, the permitting authority
would be'able to determine whether
additional information was needed and
whether to issue a permit.
In its May 27,1992 notice EPA also
proposed to extend the time period over
which permit applications must be
submitted by these "first phase"
facilities, from within 120 days after
promulgation of part 503 to within 180
days after promulgation of part 503, to
provide adequate time for applicants to
compile necessary information.
Application Information Required.
Application requirements related to
sewage sludge use or disposalwere
established by the May 2,1989, sewage
sludge permit program regulations.
Section 122!21(c)(2) requires all
treatment works'treating domestic
sewage to submit sewage sludge permit
application information to the director.
Section 122.21(d)(3)(ii) specifies which
information must be submitted, namely,
the information at § 501.15(a)(2).
Section 501.15(a)(2) requires two
types of information: general facility
information (paragraphs (i)-(vi)) and
information on sewage sludge use and
disposal practices (paragraphs (vii)-
(xii)j. The information requirements are
as follows:
(2) Information requirements. All treatment
works treating domestic sewage shall submit
to the Director within the time frames
established in paragraph (d)(l)(ii) of this
section the following information:
(i) The activities conducted by the
applicant which require it to apply for a
permit;
(ii) Name, mailing address, and location of
the treatment works treating domestic sewage
for which the application is submitted;
(iii) The operator's name, address,
telephone number, ownership status, and
status as Federal, State, private, public, or
other entity;
(iv) Whether the facility is located on
Indian lands;
(v) A listing of all permits of construction
approvals received or applied for under any
of the following programs:
(A) Hazardous Waste Management program
under RCRA.
(B) UIC program under SOW A.
(C) NPDES program under CWA.
(D) Prevention of Significant Deterioration
(PSD) program under the Clean Air Act.
(E) Nonattainment program under the
Clean Air Act.
(F) National Emission Standards for
Hazardous Pollutants (NESHAPS)
preconstruction approval under the Clean Air
Act.
(G) Ocean dumping permits under the
Marine Protection, Research, and Sanctuaries
Act.
(H) Dredge or fill permits under section
404 of CWA.
(I) Other relevant environmental permits,
including State or local permits.
(vi) A topographic map (or other map if a
topographic map is unavailable) extending
one mile beyond the property boundaries of
the treatment works treating domestic
sewage, depicting the location of the sludge
management facilities (including disposal
sites), the location of all water bodies, and
the location of wells used for drinking water
listed in the public records or otherwise
known to the applicant within V* mile of the
property boundaries;
(vii) Any sludge monitoring data the
applicant may have, including available
ground water monitoring data, with a
description of the well locations and
approximate depth to ground water, for
landfills or land application sites (see
appendix I to 40 CFR part 257);
(viii) A description of the applicant's
sludge use and disposal practices (including,
where applicable, the location of any sites
where the applicant transfers sludge for
treatment and/or disposal, as well as the
name of the applier or other contractor who
applies the sludge to land if different from
the applicant, and the name of any
distributors when the sludge will be disposed
of through distribution and marketing, if
different from the applicant);
(ix) For each land application site the
applicant will use during the life of the
permit, the applicant will supply information
necessary to determine if the site is
appropriate for land application and a
description of how the site is (or will be)
managed. Applicants intending to apply
sludge to land application sites not identified
at the time of application must submit a land
application plan which at a minimum:
(A) Describes the geographical area covered
by the plan;
-------
9364 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(B) Identifies site selection criteria;
(O Describes how sites will be managed;
(0) Provides for advance notice to the
permit authority of specific land application
silos and reasonable- time for the permit
authority to object prior to the sludge
application; and
(B) Provides for advance public notice as
required by State and local law, but in all
cases requires notice to landowners and
occupants adjacent to or abutting the
proposed land application site.
(x) Annual sludge production volume;
(xl) Any information required to determine
tho appropriate standards for permitting
under 40 CFR part 503; and
(xil) Any other information the Program
Director may request and reasonably require
to assess tho sludge use and disposal
practices, to determine whether to issue a
permit, or to ascertain appropriate permit
requirements.
For purposes of today's rule and
permit applications triggered by
promulgation of today's rule, the most
significant information requirement is
the requirement in paragraph (xi) to
submit "any information required to
determine the appropriate standards for
permitting under 40 CFR part 503." The
information requirements related to the
part 503 standards were kept general in
tho May 2,1989, rule because part 503
had not yet been promulgated. Today's
rule establishes more specific
information requirements for each use
and disposal practice. Permit applicants
must identify their chosen use and
disposal practices and submit
information which will enable the
permitting authority either to determine
compliance with the standards or to
derive site-specific pollutant limits
whore tho applicant seeks site-specific
limits as provided in today's rule. EPA
expects to issue additional guidance
detailing what information is needed for
each use and disposal practice. EPA also
is in the process of revising the NPDES
application form for POTWs, which will
include requirements for submitting
sewage sludge use and disposal
information. (Prior to rulemakings
affecting application forms, EPA intends
to issue interim application guidance to
facilitate tho collection of this
information.) EPA does not anticipate
issuing or reissuing permits to all
existing POTWs and other treatment
works treating domestic sewage at one
time. This approach, which was in the
proposed permitting rule, was
abandoned as impractical given the
severe resource burden that would
result. Instead, EPA expects that all
permits reissued after promulgation of
part 503 will contain today's standards
and that other permits will be reopened
to incorporate today's standards as
described in the discussion below on
permitting priorities. The permitting
authority will use information
submitted with the application (as well
as from other sources, such as
monitoring data submitted under the
interim permitting strategy or pursuant
to a POTW's pretreatment program) to
determine whether to issue a permit or
revoke and reissue an existing EPA-
issued NPDES permit to incorporate
today's standards.
As discussed later in the section on
who issues the permit, EPA expects to
be the permitting authority initially.
Therefore, all applications should be
submitted to the appropriate EPA
Regional office unless the applicant is
notified otherwise by EPA.
Permitting Priorities
The process of developing and issuing
permits provides the permitting
authority an opportunity to evaluate
each facility's use and disposal
practice(s) and to develop permit
conditions incorporating part 503
standards as well as additional
requirements, either as required by parts
122 or 501 or as tailored to site-specific
circumstances (e.g., more frequent
monitoring). Permit issuance also
provides additional certainty to the
permitted facility of its legal obligations,
and compliance with permit terms may
provide a defense against actions based
on violations of the part 503 standards
(see 40 CFR § 122.5 and preamble
discussion at 54 FR 18735, May 2,
1989). Thus, permits will be the primary
mechanism for implementing the
national sewage sludge program in the
long run.
As discussed above, EPA has
determined that it is not feasible to
develop and issue permits to the
estimated 16,000 to 20,000 treatment
works treating domestic sewage which
may be subject to the part 503
standards. Consequently, EPA has
proposed revisions to parts 122 and 501
to allow phased submission of permit
applications over time (57 FR 22197,
May 27,1992). Permitting authorities
must establish priorities for permit
issuance based on consideration of the
nature of the universe of facilities
ultimately required to have the part 503
standards reflected in permits.
Today's rule does not establish
priorities for issuance of permits to
treatment works treating domestic
sewage. Nonetheless, today's rule, in
combination with existing policies and
regulations, will allow permitting
authorities to establish permitting
priorities.
The Sewage Sludge Interim
Permitting Strategy (September 1989)
recommended that the following types
of POTWs be considered priorities for
purposes of interim sewage sludge
permitting: Class I sludge management
facilities (as denned by 40 CFR 122.2);
POTWs that fire sewage sludge in a
sewage sludge incinerator; and POTWs
with known or suspected problems with
their sewage sludge quality or sludge
use or disposal practices.
EPA encourages permitting
authorities to establish permitting
priorities to implement part 503
standards similar to those established by
the interim strategy, but modified in
consideration of today's rule. In general,
the general requirements, management
practices, pollutant limitations,
pathogen and vector requirements, and
monitoring, recordkeeping, and
reporting requirements in today's rule
will apply in the absence of permits.
The exception would be those facilities
that either require or seek site-specific
pollutant limitations as provided in
today's rule.
EPA believes that sewage sludge
permitting priorities should be
established as follows. In the first round
of permitting following today's rule,
permitting authorities should rely to the
maximum extent possible on the self-
implementing aspects of the part 503
standards. Permits should be issued
during the initial period after part 503
is published to those treatment works
treating domestic sewage in the
following high-priority categories, for
which the Agency believes self-
implementation is not sufficient:
Sewage sludge incinerators; surface
disposal sites requiring or requesting
site-specific permit limits; facilities
designated by the permitting authority
as posing a threat to human health and
the environment and that need to be
fully evaluated in the context of permit
development; facilities for which a
permit is deemed necessary to fully
support or promote beneficial use; and
facilities whose NPDES permits come
up for reissuance during the course of
the normal five-year permit cycle.
EPA considers sewage sludge
incinerators a high priority for permit
issuance for two principal reasons. First,
sewage sludge incinerators present a
wider exposure to sewage sludge
pollutants and therefore, are presumed
to pose a greater potential threat to
public health and the environment than
other use or disposal methods. In
addition, some of the requirements for
sewage sludge incinerators can only be
fully applied on a case-specific basis
(e.g., allowable pollutant concentrations
for sludge fed to incinerators must be
calculated from results of air dispersion
models and control efficiencies of the
unit). Similarly, certain surface disposal
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9365
sites under subpart C will be required to
apply for site-specific permit limits, and
these are being targeted for immediate
attention as part of the first phase of
permit applications.
Treatment works treating domestic
sewage that have been designated by the
permitting authority as posing a threat
to public health and the environment
should also be considered a high
priority for submission of application
information and for permitting during
the initial period following the effective
date of today's rule. Although the part
503 technical standards are designed to
protect public health and the
environment, EPA envisions certain
cases where it may be necessary for the
permitting authority to work closely
with the treatment works treating
domestic sewage to ensure that the
technical standards are properly applied
and reinforced in the context of permit
development and issuance. For
example, where the treatment works
treating domestic sewage must build
new pollution control facilities to meet
the standards, the permit can establish
compliance schedules (see § 122.47).
(Note, however, that no compliance
schedule can extend the compliance
deadline established under section
405(d)(2)(D) of the CWA.)
EPA believes that for certain
treatment works treating domestic
sewage, permit issuance will help
promote beneficial use and is, therefore,
establishing a high priority for
addressing these facilities. For such
facilities, the additional certainty
provided by a permit may aid in
reinforcing the requirements of the
applicable technical standards and may
act to reassure other parties or members
of the general public that the beneficial
use of sewage sludge is in strict
accordance with the part 503 technical
standards.
Finally, all facilities whose NPDES
permits come up for reissuance during
the normal permit cycle should include
applicable sewage sludge standards in
their permits. In addition to the above-
described categories, a large number of
sludge-only permits may be issued in
the first permit cycle following
promulgation of the part 503 standards.
The priority in which these facilities are
addressed will be based on the
permitting authorities' determination of
the threat posed to public health and the
environment by these facilities' sludge
use or disposal.
Requirements in the Absence of a
Permit
Most requirements in today's
standards are fully enforceable and can
be easily understood and applied
without translation into permit
conditions. Compliance with the
standards will be verified through the
review of self-monitoring information
and through inspection of facility
records required to be created and
maintained by the rule. However,
because some standards may be
established or adjusted based on site-
specific factors, identification of which
standards apply is necessary while
development of these site-specific
requirements is pending (e.g., after a
permit application has been submitted
but before issuance of a permit).
The part 503 standards comprise
several sets of requirements for each use
and disposal method: general
requirements, management practices,
pollutant limits, pathogen and vector
attraction requirements, monitoring
requirements, recordkeeping
requirements, and reporting
requirements. The standards applicable
to each use and disposal practice are
described in detail in this rule. In
practice, most facilities will be able to
determine from today's rule which
specific pollutant concentrations apply
to their use or disposal practices. In
addition, facilities will be able to
determine other applicable
requirements such as management
practices (e. g., to prevent sewage sludge
applied to land from entering waters of
the U.S.), monitoring requirements
based on the amount of sewage sludge
used or disposed, and recordkeeping
designed to track the various use or
disposal practices.
In the case of sewage sludge
incinerators, today's rule does not
establish national, uniform pollutant
limits for sludge quality; instead, these
limits are developed based on site
specific factors. Similarly, under certain
circumstances, pollutant limits for
surface disposal sites must be developed
based on site-specific factors. Today's
rule also allows adjustment to national
uniform pollutant limits for certain
surface disposal practices if established
in a permit. In all cases where site-
specific standards are mandated or
sought, the treatment works treating
domestic sewage must submit a permit
application with complete and accurate
information supporting the site-specific
pollutant limits. Submission of such
applications does not relieve the
applicant of the responsibility to
comply with all other applicable
portions of today's rule. In addition, as
a matter of policy, the applicant must
meet those numerical pollutant levels
which appear in its application for site-
specific pollutant concentrations during
the period after submission of a
complete permit application but prior to
the issuance of a permit containing site-
specific limits.
Who Issues the Permit
As discussed above, EPA is
responsible for issuing permits that
implement the technical standards for
sewage sludge use and disposal unless
those standards are implemented
through certain other Federal permits or
permits issued by a State with an EPA
approved sludge management program.
Currently, the only Federal program
listed in section 405 (f) with comparable
permits is the Subtitle C program under
RCRA. Today's rule adopts Subtitle C
requirements as standards under section
405(f). Thus, sewage sludge that is a
hazardous waste and facilities accepting
such sludge will continue to be
regulated under Subtitle C of RCRA.
None of the other listed Federal permit
programs is expected to implement the
standards for sewage sludge use or
disposal promulgated today.
As discussed previously, today's
standards may also be implemented
through permits issued by State
programs approved by the
Administrator as adequate to assure
compliance with section 405 of the
CWA. Under the May 2,1989
regulations, States may seek approval of
a modified NPDES program (Part 123) or
a separate, non-NPDES program (Part
501). The basic requirements for either
approach are essentially the same.
Approved State programs will share
several important features with an EPA
administered program: authority to
issue and enforce permits to POTWs
and other treatment works treating
domestic sewage that implement the
Federal technical standards and other
requirements for sewage sludge use and
disposal; authority to enforce the
technical standards against any user or
disposer of sewage sludge; and general
authority to take action to protect public
health and the environment from any
reasonably anticipated adverse effects of
sewage sludge use and disposal.
Currently, no States have received
EPA approval of their State sludge
management programs. At least initially,
EPA Regions will be responsible for
implementing the technical standards
promulgated today in all States using
the permitting requirements and
procedures in 40 CFR parts 122 and 124.
Where EPA is the NPDES permitting
authority, it will implement the
standards through NPDES permits.
Where a State has an approved NPDES
program, EPA must issue a separate
NPDES or sludge-only permit to
implement the standards. (EPA is
considering issuing guidance on joint
issuance of permits in States with
-------
9366 Federal Register/Vol. 58, No. 32 / Friday,February 19, 1993 / Rules and Regulations
approved NPDES programs). EPA may
choose to issue general permits for
sewage sludge use and disposal as an
alternative to the requirement to impose
sewage sludge conditions in individual
permits. However, until States seek and
apply for program approval, dual State
and Federal permitting programs may be
in effect. EPA encourages States to seek
program approval as soon as possible
and has published a State Sludge
Management Program Guidance (EPA
1990) to assist their efforts.
The permitting program focuses
primarily on generators of sewage
sludge. Thus, in most cases the
permitting authority will be the Region
or State in which the treatment works
treating domestic sewage is located. The
sewage sludge from these facilities that
is transported to another State will have
to moot any part 503 requirements
related to the use or disposal site unless
the sludge is transferred to a treatment
works treating domestic sewage. In this
case, the receiving treatment works
treating domestic sewage must apply for
a permit and comply with part 503
standards. When a generating treatment
works sends its sludge out of state to a
user or disposer not defined or
designated as a treatment works treating
domestic sewage, the receiving State or
local jurisdiction, may, but need not,
issue a permit. (Some States under their
own laws and programs require sludge
exporters to obtain any necessary
approvals from importing States,
although this currently is not required
by Federal regulation. Today's
rulemnking does, however, require
notification to the permitting authority
in the receiving State in cases where
bulk sewage sludge is sent out of State.)
EPA administration of the new
sewage sludge permitting program will
not displace existing State sewage
sludge management programs (unless a
State so chooses by seeking EPA
approval of its program). Likewise,
under section 510 of the CWA, States
may impose more stringent
requirements than those promulgated in
today's technical standards and those in
the permitting requirements and State
program rule. However, more stringent
State requirements generally will not be
considered a part of the Federal program
(i.e., they may not be Federally
enforceable and would not be
considered a part of an EPA-approved
State sludge management program). The
only exception will be where an EPA
permit writer makes a determination in
an individual permit proceeding that, in
the particular special circumstances
more stringent State requirements are
necessary to protect public health and
the environment as provided in section
405(d)(4) of the CWA.
EPA encourages States to adopt the
part 503 standards as part of State law.
The part 503 standards result from years
of data gathering and analysis and
represent a comprehensive and
extensive evaluation of the fate and
effect of sewage sludge in the
environment. Today's standards have
undergone extensive scrutiny by the
public and scientific community.
Adoption of the part 503 standards as a
minimum baseline for sewage sludge
use or disposal will protect public
health and the environment. In
addition, widespread adoption of part
503 standards would facilitate beneficial
use of sewage sludge (biosolids) by
establishing uniform standards from
State to State.
Implementation Strategy
EPA has developed and is carrying
out an overall strategy to help ensure
that today's rule is implemented
expeditiously and in a manner that
protects public health and the
environment. This strategy includes a
commitment to conduct public outreach
to ensure that the regulated community
and the public have an opportunity to
become familiar with the part 503
standards and to ask questions regarding
the implementation and enforcement of
the rale.
As indicated previously, the Agency
will rely heavily on the self-
implementing nature of the part 503
standards during the initial period after
promulgation and will phase in permits
incorporating the standards over a 5-
year period. To familiarize affected
facilities with the part 503 requirements
applicable to them before standards are
incorporated into their permits, EPA
will mail informational material on the
standards and permit application
requirements directly to treatment
works treating domestic sewage.
Outreach will also include co-
sponsoring public workshops with
several national trade associations,
making presentations at various other
conferences, and responding to
individual inquiries.
Another key element of EPA's
implementation strategy will be
educating EPA and State personnel on
the new standards. This effort will
entail training courses and issuance of
guidance documents and other materials
covering various aspects of
implementation. For example, EPA will
issue a permit writer's guidance,
updating the Guidance for Developing
Case-by-Case Permit Conditions for
Municipal Sewage Sludge issued by
EPA in 1990. The new guidance
document will provide direction for
incorporating the part 503 technical
standards into permits. In addition, the
Agency will develop and issue various
documents (and, in some cases,
revisions to existing materials) covering
the compliance and enforcement
components of its sludge
implementation strategy.
Part XIII: Benefits and Costs of the
Amendments to Parts 257 and 403 and
the Final Part 503 Regulation
Data used to calculate estimates
reported in this preamble are detailed in
the Regulatory Impact Analysis (RIA).
This work relies heavily on data
collected during the National Sewage
Sludge Survey but it is also augmented,
as appropriate, by relevant data from the
1988 Needs Survey and other available
sources of information.
The data presented here differ from
that presented in the 1990 Notice of
Data Availability for several reasons.
First, the final regulatory definitions for
use or disposal practices were
developed after publication of the notice
and these regulatory definitions are
somewhat different than those
definitions used in development of the
survey and publication of the notice.
For example, the practices of land
application and distribution and
marketing were combined under one
definition. Second, detailed analyses
conducted after publication of the
notice indicated that responses meeting
case by case quality control checks did
not appear to be correct when
considered in relation to responses at
other POTWs. For example, survey
responses for the amount of sewage
sludge used or disposed were
investigated for several POTWs after
comparison of responses with those of
POTWs with similar flow rates
indicated a potential problem. These
investigations are documented in the
"Statistical Support Document for the
40 CFR part 503 Rule for Sewage Sludge
Use or Disposal". Third, the statistical
weighting scheme for the survey was
not fully implemented when the notice
was published; those summary statistics
not using the weighting scheme were
presented by reported flow group.
Finally, the summary statistics
published in the notice were based on
information from the NSSS. The NSSS
was only designed to cover POTWs that
practice secondary and better
wastewater treatment. However, this
regulation also covers POTWs that only
practice primary treatment, privately
owned treatment works, Federally owed
treatment works, and domestic septage
haulers.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9367
This part of the preamble discusses
the benefits and costs of the
amendments in today's rulemaking to
Parts 257 and 403 and the benefits and
costs of the final part 503 regulation.
More details on the benefits and costs of
the final part 503 regulation are
presented in the Regulatory Impact
Analysis for the part 503 Regulation (see
Part XTV for information on how to
obtain a copy).
This part of the preamble is divided
into three sections. The first and second
sections provide information on the
generation of sewage sludge and the use
or disposal of sewage sludge,
respectively. The third section discusses
the benefits and costs of the
amendments to parts 257 and 403 and
the benefits and costs of the final part
503 regulation.
Generation of Sewage Sludge
The Clean Water Act requires that
municipal wastewater meet certain
requirements before it can be discharged
to the nation's waters. To meet those
requirements, the wastewater usually
must be treated. Solid, semi-solid, and
liquid residues generated during
wastewater treatment must be used or
disposed properly. These residues must
be managed properly through final use
or disposal.
Municipal wastewater contains
materials discharged into household
drains through toilets, sinks, and tubs.
These materials are domestic sewage.
Components of domestic sewage
include soaps, shampoos, human
excrement and tissue, food stuffs,
detergents, pesticides, household
hazardous waste, and oil and grease.
Typically, a family of four generates 300
to 400 gallons of domestic sewage
wastewater per day.
Domestic sewage may be treated (or
partially treated) at its source in such
devices as septic tanks and portable
toilets or domestic sewage may be
treated in publicly owned, privately
owned, or federally owned treatment
works. A treatment works may treat
domestic sewage alone or in
combination with liquid industrial
wastewater. Residues generated during
the treatment of domestic sewage are, by
definition, sewage sludge.
Treatment works treat municipal
wastewater to a certain level of
treatment (i.e., primary, secondary, or
tertiary). Each level of treatment results
in greater amounts of sewage sludge.
Primary treatment processes remove
the solids that settle out of the
wastewater by gravity. This level
generates 2,500 to 3,500 liters of sewage
sludge per million liters of wastewater
treated. Primary sewage sludge contains
3 to 7 percent solids, 60 to 80 percent
of which is organic matter. The water
content of primary sewage sludge can
easily be reduced by dewatering the
sewage sludge.
Secondary treatment produces a
sewage sludge generated by biological
treatment processes. These processes
(e.g., activated sewage sludge systems
and trickling filters) use microbes to
break down and convert the organic
substances in the wastewater to
microbial residue. Biological treatment
processes remove up to 90 percent of
the organic matter in the wastewater
and produce a sewage sludge that
typically contains from 0.5 to 2 percent
solids. Sewage sludges produced during
secondary treatment generally are more
difficult to dewater than are primary
sewage sludges. The organic content of
secondary treatment sewage sludge
ranges from 50 to 60 percent. Secondary
treatment processes increase the volume
of sewage sludge generated over the
volume generated in primary treatment
by 15,000 to 20,000 liters of sewage
sludge per million liters of wastewater.
Advanced wastewater treatment
processes (e.g., chemical precipitation
and filtration) also increase the volume
of sewage sludge to be used or disposed.
In chemical precipitation, chemicals are
added to the wastewater to remove
organic materials and nutrients and to
separate the solids from the wastewater.
Characteristics of these sewage sludges
vary, depending on the type of
advanced treatment process used and
the characteristics of the wastewater in
the influent to the treatment process.
The solids content of advanced
treatment sewage sludges varies from
0.2 to 1.5 percent, while the organic
content of the sewage sludge ranges
from 35 to 50 percent.
Advanced treatment increases the
volume of sewage sludge generated over
the volume generated during secondary
treatment by 10,000 liters of sewage
sludge per million liters of wastewater.
Before dewatering, sewage sludge
contains from 93 to 99.5 percent water.
The remaining portion is the solids and
dissolved material removed from the
wastewater, added in the treatment
process, or cultured by the wastewater
treatment process. Virtually all sewage
sludges contain nutrients (e.g., nitrogen,
phosphorus) and pathogens (e.g.,
bacteria, viruses, protozoa, and viable
helminth ova). Some sewage sludges
also contain more than trace amounts of
organic chemicals (e.g., chloroform) and
inorganic chemicals (e.g., iron). These
pollutants occur in domestic sewage,
industrial wastewater discharge to
municipal sewers, and runoff from
parking lots and other areas that enters
the sewers.
Before using or disposing of sewage
sludge, treatment works generally
thicken, stabilize, and dewater the
sewage sludge. This thickening is a
process in which water from the sewage
sludge is removed to achieve a volume
reduction. The reduction in sewage
sludge volume decreases the capital and
operating costs of subsequent sewage
sludge processing and use or disposal
practices by decreasing the volume of
sewage sludge to be processed. For
example, lowering the volume of sewage
sludge to be used or disposed reduces
transportation costs. EPA estimates that
the cost to transport sewage sludge with
a 22 percent solids content over a 20-
mile trip is about one-half the cost to
transport sewage sludge with a 6
percent solids content over the same
distance.
Treatment works frequently digest
sewage sludge to reduce the level of
pathogens and odors. The degree to
which a sewage sludge is processed is
very important when it is applied to
land or placed on a surface disposal site.
Use or Disposal of Sewage Sludge
Three of the more common use or
disposal practices for sewage sludge are
application to the land, placement on a
surface disposal site, and firing in a
sewage sludge incinerator. Sewage
sludge is applied to the land either to
condition the soil or to fertilize crops or
vegetation grown on the land. In
contrast, sewage sludge is placed on the
land in surface disposal for final
disposal. In most cases, crops are not
grown on surface disposal sites. In
incineration, the organic and inorganic
materials in sewage sludge are
combusted in the incinerator.
As mentioned previously, the purpose
of applying sewage sludge to the land is
to condition the soil using the organic
material in the sewage sludge or to
fertilize crops or vegetation grown on
the land. Approximately 33 percent of
the sewage sludge used or disposed
annually is applied to land. The method
of applying sewage sludge to the land
depends on the physical characteristics
of the sewage sludge (e.g., liquid or
dried) and the site conditions. Liquid
sewage sludge can be applied with
tractors, tank wagons, irrigation
systems, or special application vehicles.
Liquid sewage sludge also can be
injected under the surface layer of the
soil. Dewatered sewage sludge, on the
other hand, typically is applied to the
land by equipment similar to that used
for applying limestone, animal manures,
or commercial chemical fertilizers.
Generally, the dewatered sewage sludge
-------
9368 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
is applied to the land surface and then
incorporated by plowing or disking,
except when applied to pasture. Sewage
sludge is applied to areas such as
agricultural land, forest, public contact
sites, reclamation sites, lawns, and
home gardens.
Sewage sludge is a valuable source of
fertilizer when applied to agricultural
land. Results of a study of sewage
sludge and effluent use on selected
agricultural crops in one area of Oregon
found that the return per acre associated
with sewage sludge application ranged
from a loss of $6 to an increase of $15
per acre when compared to traditional
fertilizer sources. The return per acre
depended on crop rotation, previous
soil management practices, soil type,
and level of sewage sludge application.
The savings were net savings in the cost
of fertilizers, taking into account the fact
that the sewage sludge was available at
no cost to the fanner (Reference No. 10).
Sewage sludge has been applied to
forests, at least on an experimental field-
scale level, in 10 or more States. The
most extensive experience with this
practice is in the pacific Northwest.
Liquid sewage sludge is most often
sprayed from mobile equipment into
established forest stands. Application of
SQWQgo sludge to forest shortens wood
production cycles by accelerating tree
growth, especially on marginally
productive soils. Results of studies at
the University of Washington on the use
of sewage sludge as a fertilizer in
silviculture operations show height
increases of up to 1,190 percent and
diameter increases of up to 1,250
percent compared with controls in
certain tree species. These results have
also shown that trees grow twice as fast
on sewage sludge-amended soil. Thus, a
tree that typically would be cut after 60
years could be cut after only 30 years.
If sewage sludge is used to stabilize
and revegetate land at a reclamation
site, typically large amounts of sewage
sludge (usually 50 to 100 or more metric
tons per hectare) are applied to the site
on a short-term basis. Sewage sludge
may be applied only one time or may be
applied as many as two to three times.
A large amount of sewage sludge is
applied to a reclamation site to provide
the amount of organic matter needed to
establish a self-sustaining ecosystem.
Costs to reclaim land with sewage
sludge are comparable to the costs of
land reclamation using other
commercial materials. For example, in a
strip-mined area in Fulton County, IL,
sites reclaimed using sewage sludge cost
$3,660 an acre; costs for sites reclaimed
using other commercial materials range
from $3,395 to $6,290 an acre. Other
examples include the use of
Philadelphia's sewage sludge to reclaim
more than 3,000 acres of devastated
lands in Pennsylvania and the use of
sewage sludge, in combination with fly
ash, to revegetate contaminated soils in
Palmerton, PA.
Sewage sludge may be placed on the
land for final disposal. Land where the
sewage sludge is placed for this purpose
is a surface disposal site. The surface
disposal site may contain a series of
trenches, dug into the ground, into
which dewatered sewage sludge is
deposited. Sewage sludge also may be
placed on the land surface (e.g., a
sewage sludge pile). In surface disposal,
usually no attempt is made to use
nutrients in the sewage sludge. As
mentioned previously, sewage sludge is
placed on a surface disposal site for
final disposal.
Approximately one-third of the
sewage sludge used or disposed by
POTWs (NSSS Questionnaire Survey) is
landfilled with municipal solid waste.
In co-disposal, the absorption
characteristics of the solid waste and
soil conditioning characteristics of the
sewage sludge complement each other.
The solid waste absorbs excess moisture
from the sewage sludge and reduces
leachate migration. Sewage sludge
usually makes up 5 percent or less of
the material in a municipal solid waste
landfill.
Incineration is a disposal practice in
which organic and inorganic material in
sewage sludge are combusted in an
enclosed device. Estimates from the
NSSS Questionnaire Survey show
approximately 52 percent (110) of the
existing secondary and advanced
treatment sewage sludge incinerators
were built prior to 1973. Multiple hearth
incinerators are the most common type
of sewage sludge incinerator with 156
multiple-hearth incinerators (74 percent
of the incinerators firing sewage sludge),
49 fluidized-bed incinerators (23
percent of the total), 3 flash-drying
incinerators, and 2 electric furnaces.
The estimated amount of sewage sludge
fired in secondary and advanced
treatment sewage sludge incinerators in
1988 was 736,000 dry metric tons,
which is approximately 16 percent of all
sewage sludge used or disposed by
secondary or advanced treatment works.
An additional 128,000 dry metric tons is
estimated to be incinerated by primary
treatment works. Not represented in this
estimate are incinerators that fire
sewage sludge with solid waste in
municipal waste combustors. The
Agency estimates that seven facilities
practice co-incineration of sewage
sludge with municipal solid waste.
Approximately 12,750 POTWs use or
dispose 5.4 million dry metric tons of
sewage sludge annually (NSSS
Questionnaire Survey) or 47 pounds of
sewage sludge (dry weight basis) for
every individual in the United States.
Privately owned and federally owned
treatment works also use or dispose of
sewage sludge. The amount of sewage
sludge used or disposed by these
treatment works is unknown, but it is
estimated to be no more than 0.1 million
dry metric tons per year.
The volume of domestic septage used
or disposed annually is significant. EPA
estimates that up to 8.6 billion gallons
of domestic septage are used or
disposed annually, of which
approximately half is discharged to
POTWs and half is either land applied,
placed on a surface disposal site, or
placed in a lagoon for treatment.
Tables XIII-1 and XIII-2 present the
amount of sewage sludge used or
disposed annually by use or disposal
practice for secondary and advanced
treatment POTWs and for primary
treatment POTWs, respectively, based
on the flow rate of the POTWs as
presented in the 1988 NSSS. Table XIII-
3 presents the number of POTWs
employing each use or disposal practice,
as estimated in the 1988 National
Sewage Sludge Survey for secondary
and advanced treatment POTWs. The
number of primary treatment POTWs
employing each use or disposal practice,
based on information from the 1988
Needs Survey, is presented in Table
XIII-4.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9369
TABLE XIII-1 .—AMOUNT OF SEWAGE SLUDGE USED OR DISPOSED BY SECONDARY AND ADVANCED TREATMENT POTWs
BY USE OR DISPOSAL PRACTICE AND FLOW RATE
[Thousands of Dry Metric Tons]
Use or disposal practice
Land Application
Agriculture
Public Contact
Sale
Undefined
Surface Disposal
Landspreading
Monofill
Other
Not Regulated
Unknown
Ocean Disposal *
Other
Transfer
Total
Percent of Total
Flow rate group
>100 MGD
320.0
255.0
117.8
11.5
2.3
47.0
47.8
25.4
3.3
39.2
15.3
2.4
21.5
386.2
141.7
141.7
0.0
N/A
1,142.0
25.0
>10-100
MGD
308.5
586.7
349.3
58.7
23.1
53.2
6.9
24.7
70.8
240.4
113.5
72.9
54.0
614.2
143.2
143.2
0.0
N/A
1,893.1
41.5
>1-10 MGD
106.1
499.9
398.6
28.5
0.3
36.7
1.0
10.4
24.4
110.2
57.6
38.2
14.5
456.3
0.7
0.7
0.0
N/A
1,173.3
25.7
£1 MGD
1.7
178.1
131.3
29.3
1.0
4.6
0.3
0.1
11.7
81.6
33.9
20.6
27.1
91.9
0.0
0.0
0.0
N/A
353.4
7.7
Total
amount
used or dis-
posed
736.3
1,519.7
997.0
128.0
26.7
141.4
56.1
60.5
110.1
471.4
220.4
134.0
117.0
1,548.6
285.7
285.7
0.0
N/A
4,561.8
100
Use or dis-
posal prac-
tice as per-
cent of total
16.1
33.3
21.9
2.8
0.6
3.1
1.2
1.3
2.4
10.3
4.8
2.9
2.6
33.9
6.3
6.3
0.0
N/A
100
Note: Numbers may not add up to 100 percent because of rounding.
N/A indicates the value was not available.
•The NSSS data reflects use or disposal practices at the time the data was collected. The Ocean Dumping Ban Act of 1988 generally banned ocean dumping of
sewage sludge by December, 1991. The last dumping ceased in June 1992.
Source: 1988 National Sewage Sludge Survey (Questionnaire), EPA.
TABLE XI11-2.—AMOUNT OF SEWAGE SLUDGE USED OR DISPOSED BY PRIMARY TREATMENT POTWs BY USE OR DISPOSAL
PRACTICE AND FLOW RATE
[Thousands of Dry Metric Tons]
Use or disposal practice
Land Application
Surface Disposal
Not Regulated
Unknown
Total
Flow rate group
>100 MGD
62.9
129.9
40.3
132.4
24.4
390.0
49.0
>10-100
MGD
38.0
78.3
24.3
79.9
14.7
235.2
29.6
>1-10 MGD
18.7
38.6
12.0
39.3
7.3
115.8
14.6
S1 MGD
8.8
18.1
5.6
18.5
3.4
54.4
6.8
Total
amount
128.4
265.0
82.2
270.0
49.8
795.4
100
Percent of
total
16.1
33.3
10.3
34.0
6.3
100
Note: Numbers may not add up to 100 percent because of rounding.
Source: Estimated from 1988 Needs Survey and 1988 National Sewage Sludge Survey (Questionnaire), EPA.
TABLE XIII-3.—NUMBER OF POTWs USING A USE OR DISPOSAL PRACTICE AND THE AMOUNT OF SEWAGE SLUDGE
USED OR DISPOSED BY SECONDARY AND ADVANCED TREATMENT POTWs
Use or disposal practice
Land Application .
Agriculture
Compost
Forests
Public Contact
Reclaimed
Sale
Undefined . .
Surface Disposal
I andspreading
Monoflll
Other
Not Regulated
Unknown
Ocean Disposal*
POTWs using a practice
Number
327
3,988
3,246
146
30
254
69
199
487
1,157
383
320
455
2,595
3,535
115
Percentage
of POTWs
3.0
36.6
29.8
1.3
0.3
2.3
0.6
1.8
4.5
10.6
3.5
2.9
4.2
23.8
32.5
1.1
Sewage sludge used dis-
posed
Amount
(thousands
of dry metric
tons)
736.3
1,519.7
997.0
128.0
26.7
141.4
56.1
60.5
110.1
471.4
220.4
134.0
117.0
1,548.6
285.7
285.7
Percentage
of total
amount
16.1
33.3
21.9
2.8
0.6
3.1
1.2
1.3
2.4
10.3
4.8
2.9
2.6
33.9
6.3
6.3
-------
9370 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
TABLE XIII-3.—NUMBER OF POTWs USING A USE OR DISPOSAL PRACTICE AND THE AMOUNT OF SEWAGE SLUDGE
USED OR DISPOSED BY SECONDARY AND ADVANCED TREATMENT POTWs—Continued
Use or disposal practice
OttTOf
Transfer .»..
Total
POTWs using a practice
Number
3,398
22
12,046
Percentage
of POTWs
31.2
0.2
100
Sewage sludge used dis-
posed
Amount
(thousands
of dry metric
tons)
0
N/A
4,561.8
Percentage
of total
amount
0.0
N/A
100
Notes: The total 12,048 Indicates the total number of subpractlces at the 10,893 POTWs. For Land Application and Surface Disposal practices, the numbers of
subpracticos do not total the number of POTWs practicing a use or disposal practice because some POTWs use more than one subpractlce. Percentage of POTWs
t» tho percentage of the 10,893 Secondary and Advanced Treatment POTWs. Numbers may not add up to 100 percent because of rounding. N/A Indicates the value
is not avatiabio.
*Tho NSSS data reflects use or disposal practices at the time the data was collected. The Ocean Dumping Ban Act of 1988 generally banned ocean dumping of
sewage sludgo by December, 1991. The last dumping ceased In June 1992.
Source: 1988 National Sewage Sludge Survey (Questionnaire), EPA.
TABLE XIII-4.—NUMBER OF POTWS
USING A USE OR DISPOSAL PRACTICE
AND THE AMOUNT OF SEWAGE SLUDGE
USED OR DISPOSED BY THE POTWs
PRIMARY TREATMENT POTWs
Uso or dis-
posal
practice
Indoor-
ation .....
Land ap-
plication
Surface
Disposal
NotRogu-
latod
Unknown .
Total .
POTWs using a
practice
Number
53
669
193
395
545
1,855
Percent
of
POTWs
2.9
36.1
10.4
21.3
29.4
100
Sewage sludge used
or disposed
Amount
(thou-
sands of
dry metric
tons)
128.4
265.0
82.2
270.0
49.8
795.4
Percent
of total
amount
16.1
33.3
10.3
34.0
6.3
100
Noto: Numbers may not add up to 100 percent
because ol rounding.
Source: Estimated from 1988 Needs Survey and
1968 National Sewage Sludge Survey
(Questionnaire), EPA.
Benefits and Costs of Today's
Rulemaking
As mentioned previously, today's
rulemaking contains an amendment to
40 CFR part 257, an amendment to 40
CFR part 403, and the final part 503
regulation (40 CFR part 503). Benefits
and costs of each of these actions are
presented in this part of the preamble.
Executive Order 12291 requires EPA
to prepare a Regulatory Impact Analysis
(RLA) for major regulations, which are
defined by certain levels of costs and
impacts. For example, the Executive
Order specifies that a regulation
imposing an annual cost and benefits to
tho economy of $100 million or more is
considered "major" under the terms of
tho Order, According to the Executive
Order, the RIA should contain
descriptions of both potential costs and
benefits.
Amendment to 40 CFR Part 257
The amendment to part 257 in today's
rulemaking removes sewage sludge
subject to the standards in the part 503
from the part 257 requirements, The
final part 503 regulation now contains
the requirements to be met if sewage
sludge is applied to the land, placed on
a surface disposal site, or fired in a
sewage sludge incinerator.
The part 257 amendment in today's
rulemaking has no costs because this
action only amends the applicability of
the part 257 regulation; therefore, the
requirements in Executive Order 12291
do not apply to the amendment.
Amendment to 40 CFR Part 403
The amendment to part 403 in today's
rulemaking adds two lists of pollutants
to part 403 that are eligible for a removal
credit with respect to the use or disposal
of sewage sludge. A POTW may grant a
removal credit for the pollutants on the
two lists if all other applicable
requirements are met.
The part 403 amendment in today's
rulemaking has no costs. This
amendment is expected to result in cost
savings to industrial dischargers who
receive a removal credit for a pollutant;
therefore, the requirements in Executive
Order 12291 do not apply to the
amendment.
40 CFR Part 503
Based on EPA's estimate of the
incremental costs of complying with the
final part 503 regulation, the Agency
does not consider the final part 503
regulation to be a major rule as defined
in Executive Order 12291. However,
EPA has prepared an extensive analysis
of the benefits, costs, and other impacts
associated with the final part 503
regulation. This analysis, "Regulatory
Impact Analysis of the part 503
Regulation for Sewage Sludge Use or
Disposal," is part of the administrative
record for the final part 503 regulation.
Copies of the RIA may be obtained from
the National Technical Information
Service (see section XIV of this
preamble).
The part 503 RIA was forwarded to
the Office of Management and Budget
(OMB) with today's rulemaking. OMB's
comments are presented in the part 503
administrative record.
As mentioned previously, the part 503
RIA contains an analysis of the benefits,
costs, and economic impact associated
with the final part 503 regulation. The
analysis begins with an assessment of
the sewage sludge use or disposal
practices currently used by publicly
owned, privately owned, and federally
owned treatment works and by domestic
septage haulers. The RIA then evaluates
the impact of new or additional
requirements imposed by the final part
503 regulation.
The Agency's overall approach to the
RIA recognizes that, in addition to
compliance costs for management
practices and monitoring, record-
keeping, and reporting, a POTW or other
affected entity may be required to alter
a current practice for sewage sludge use
or disposal to achieve compliance with
the final part 503 regulation. These
changes could include shifts to a new or
different combination of use or disposal
practices or increased reliance on
industrial pretreatment. The costs of
these changes are evaluated for each
part 503 use or disposal practice for
which changes must occur. The benefits
associated with complying with the
regulation in the form of reduced health
risks are also evaluated. The RIA
presents quantitative estimates of these
benefits, expressed as a reduction in the
number of cancer cases and other health
effects.
For the use or disposal practices
subject to the final part 503 regulation,
the Agency projects incremental annual
compliance costs of $45.9 million
annually (in 1992 dollars), or an average
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9371
of less than $1 per household served.
Total annual costs include management
practice costs; monitoring, record
keeping, and reporting costs, and in a
few cases, costs for a change in use or
disposal practices.
Benefits of the final part 503
regulation are reduced effects on public
health resulting from reduced exposure
to pollutants in sewage sludge. EPA
estimates that the benefits of the final
part 503 are an annual reduction of less
than 1 cancer case and 90 to 600 cases
of identified adverse health effects. The
final regulation also is expected to
create certain environmental benefits as
a consequence of improvements in
managing the use or disposal of sewage
sludge. Table Xni-5 presents a summary
of the costs and benefits of regulating
land application (subpart B), surface
disposal (subpart C), and incineration
(subpart E). Subpart D (pathogen and
vector attraction reduction) costs are
incorporated in the costs for subparts B
and C, as appropriate. Benefits of
subpart D are not calculated because no
methodology has yet been developed to
quantify the risks from pathogens in
sewage sludge.
TABLE XI11-5.—ESTIMATED ANNUAL COSTS AND BENEFITS FOR ALL AFFECTED TREATMENT WORKS AND FIRMS To COMPLY
WITH THE PART 503 REGULATION
[$000]
Benefits
Subpart B"
Subpart C"
Subpart E
Other Costs'"
Total Costs/Benefits ...
Costs
$14 182
18335
11 703
1 675
$45895
Cancer
0-0 5
0-007
009
009-07
Non-cancer
0—500
<•)
90
90-600
•Costs for Subpart D are incorporated Into the costs of meeting Subparts B and C.
b Costs of reading and interpreting the regulation and obtaining copies of Part 258 permits.
Source: Prepared by ERG and Abt for EPA.
The feasibility of pretreatment by
industrial dischargers as a compliance
alternative was evaluated as part of the
final part 503 RIA. Land applying
POTWs that failed the ceiling limits
were analyzed to determine whether
their host industries were likely to be
causing high levels of the pollutant or
pollutants that failed ceiling limits. In
all cases, firms could be identified,
based on the NSSS, that are considered
likely contributors of these problem
pollutants. Costs for more aggressive
pretreatment programs at these firms
were developed and used in the
identification of the most likely
compliance strategy. Where EPA
determined that pretreatment was the
most likely compliance strategy, the cost
of pretreatment was used as the cost of
compliance in the RIA. Furthermore,
some POTWs practicing land
application of sewage sludge currently
cannot meet the part 503 pollutant
concentration limits for land application
of sewage sludge. Additionally, a few
POTWs that fire sewage sludge in
sewage sludge incinerators must install
state-of-the-art pollution control
equipment for metals to meet the part
503 requirements. These POTWs have a
strong motivation to institute
pretreatment to make the use or disposal
of sewage sludge easier and less ,
expensive. :
In the RIA for the proposed part 503
regulation, the Agency conducted a
limited number of case studies on the
effect of industrial pretreatment on
sewage sludge quality. Results of this
study are presented as an appendix in
the RIA for the final part 503 regulation.
In this study, pollutant removals were
estimated for all industrial dischargers
subject to covered categorical
pretreatment standards. EPA found, in
these cases, that an increase in
industrial pretreatment provides a
significant reduction in the
concentration of pollutants in sewage
sludge in cases where the pollutant
concentrations are high (it becomes
increasingly difficult to reduce pollutant
concentrations as the pollutant
concentrations decline). The percentage
reduction in pollutant concentrations in
the case studies ranged from 6 to 96
percent. Most likely, many POTWs
currently predicted to be unable to meet
pollutant concentration limits in the
land application subpart (and thus
required to maintain records of the
cumulative loadings of pollutants for
each site to which sewage sludge is
applied) could reduce the pollutant
concentrations in the sewage sludge
through a more stringent pretreatment
program. This program would focus on
the one or two pollutants for which the
part 503 pollutant concentration cannot
be met (most POTWs fail land
application pollutant concentrations
only for one or two pollutants).
a, Any reduction in pollutant
concentrations because of pretreatment,
however slight, achieved by POTWs
firing sewage sludge in a sewage sludge
incinerator that fails limits for metals
could reduce the costs of compliance
and make achieving compliance with
subpart E of the final part 503 regulation
easier overall. Without reductions in
certain pollutants, several POTWs may
need to monitor operations of the
sewage sludge incinerator very closely
to ensure that subpart E requirements
are met.
The RIA for the final part 503
regulation contains some data
limitations. The NSSS solved many of
the data problems associated with the
RIA for the proposed part 503
regulation. In addition, data gathering
activities for privately and Federally
owned treatment works and for
domestic septage haulers that apply
domestic septage to agricultural land,
forest, or a reclamation site reduced
some other limitations of the RIA for the
proposed regulation. Some data
limitations still exist, however.
Data for privately and Federally
owned treatment works are still very
limited. Numbers of privately owned
treatment works were estimated from
permits. Since only a few states collect
data on use or disposal practices for
privately owned treatment works, the
Agency had to extrapolate the
distribution of use or disposal practices
using data from relatively few states to
apply to the total population of
privately owned treatment works.
Information on Federally owned
treatment works, outside of numbers of
treatment works, is unavailable. For this
reason, the distribution of use or
disposal practices estimated for
privately owned treatment works was
applied to Federally owned treatment
works. In terms of flow rates, these two
types of treatment works are similar. For
this reason, EPA assumed that similar
-------
9372 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sowogo sludge use or disposal options
are available to both types of treatment
works.
Information on domestic septage
haulers also is very limited. The Agency
now has estimates of numbers of
domestic septage haulers and typical
use or disposal practices, but it has had
to make estimates of the distribution of
use or disposal practices based on
limited information from a relatively
fow states where data on domestic
soptogo haulers are collected.
Another limitation of the RIA is that,
in some cases, EPA had to make
assumptions about how POTWs would
comply with the regulation. For
example, the Agency assumed that
nearly all POTWs that fire sewage
sludge in a sewage sludge incinerator
would elect to continue the practice of
Incineration. Some POTWs may decide,
however, that it is less expensive to
cease incineration and shift, for
example, to land application. (Several
POTWs that fire sewage sludge in
sewage sludge incinerators generate
sewage sludge that could meet the
pollutant concentration limits for land
application, and many could meet the
cumulative limits using reasonable
agronomic application rates.) For
simplicity, the Agency calculated the
costs of installing and operating
pollution control equipment for metals
needed for these POTWs to comply with
the regulation, which in some cases
might overstate the expense of the
regulation if POTWs do decide to shift
to another use or disposal practice. In
all cases where simplifying assumptions
such as this were made, the
assumptions tended to overestimate
costs of the regulation slightly, rather
than underestimate costs.
A number of limitations affect the
estimates of risk reduction (i.e., benefits)
in the part 503 regulation. These
limitations include the exclusion of
certain exposure pathways, pollutants,
and health effects from the estimates
and the lack of ability to account for
population growth and mobility.
Overall, however, EPA is confident
that the compliance costs presented in
the part 503 RIA reflect decisions
POTWs and other entities are likely to
make, as well as costs associated with
those decisions. EPA also is confident
that the benefits presented in the RIA
are reasonable estimates of reductions in
risk associated with the final part 503
regulation. In presenting the part 503
RIA, EPA divided the regulated entities
into the five major groups: primary
treatment POTWs, secondary and
advanced treatment POTWs, privately
owned treatment works, Federally
owned treatment works, and domestic
septage haulers. Most of the analysis
focuses on secondary and advanced
treatment POTWs, for which the Agency
has the most information (i.e.,
information from the NSSS).
As noted in part III of today's
preamble, data on sewage sludge quality
were collected from about 200
secondary or advanced treatment
POTWs during the NSSS. These data
were compared to the applicable
pollutant limits in the final part 503
regulation to determine whether the
sewage sludge used or disposed at each
POTW could meet those limits. Results
of this comparison were extrapolated to
the national level using the NSSS
statistical weighing factors.
Any survey POTW that failed the part
503 pollutant limits given existing
conditions, such as sewage sludge feed
rates or land application rates, were
then evaluated further to develop a
compliance strategy for the POTW.
Costs of the compliance strategy were
then developed. A failure could be
either regulatory or economic. For
example, in the case of land application,
if either application rates or site lives
had to be reduced, a cost to deal with
reductions in site lives or application
rates had to be incurred. Costs to make
changes to current use or disposal
practices to meet part 503 requirements
were then added to costs estimated for
management practices, monitoring,
record keeping, and reporting and then
extrapolated to the national level.
To determine costs of compliance for
primary treatment POTWs, the Agency
determined that compliance costs for
primary treatment POTWs are similar to
costs for secondary or advanced
treatment POTWs. This is based on the
Agency's determination that pollutant
concentrations in sewage sludge from
primary treatment POTWs are likely to
be no worse than those in sewage sludge
from secondary or advanced treatment
POTWs for the part 503 pollutants of
concern. (SAIC 1991 Memorandum from
Kathleen Stralka and Scott Henderson,
to Chuck White, EPA, re: Nonparametric
tests of hypothesis concerning pollutant
concentrations in primary and
secondary sewage sludge for 40-City
Study Data, August 28). Compliance
costs developed for each use or disposal
practice and for each reported flow rate
group investigated in the RIA (greater
than 100 million MGD, greater than 10
MGD but equal to or less than 100 MGD,
greater than 1 MGD but equal to or less
than 10 MGD, and equal to or less than
1 MGD) were applied to the appropriate
primary treatment POTWs. For example,
per-POTW costs were estimated for
secondary and advanced treatment
POTWs with a flow rate greater than 10
MGD but equal to or less than 100 MGD
that practice land application. These
per-POTW costs included management
practice, monitoring, record keeping,
and reporting costs, as well as any
compliance costs associated with
sewage sludge quality. The per-POTW
cost was then applied to all primary
treatment POTWs with a flow rate
greater than 10 MGD but equal to or less
than 100 MGD and that practice land
application (data on flow rate and use
or disposal practice for primary
treatment POTWs were estimated based
on EPA's 1988 Needs Survey because
the NSSS did not survey that type of
treatment works).
To estimate costs of compliance for
privately and Federally owned
treatment works, the Agency assumed
that the sewage sludge quality of these
treatment works is similar to that of the
smallest POTWs surveyed in the NSSS
because both privately and Federally
owned treatment works typically have a
flow rate less than 1 MGD. The per-
POTW costs developed for the smallest
POTWs in the NSSS were applied,
based on use or disposal practice, to the
estimated number of privately and
Federally owned treatment works that
employ each use or disposal practice in
the same way discussed previously for
primary POTWs.
Compliance costs for domestic
septage haulers were calculated
differently because the final part 503
regulation imposes different
requirements for the use or disposal of
domestic septage. Part 503 does not
require domestic septage applied to
agricultural land, forest, or a
reclamation site to meet pollutant
concentration limits. Part 503, however,
does require either ground-water
monitoring or a certification that
ground-water is not contaminated with
nitrogen as a result of domestic septage
placed on a surface disposal site.
Because of the cost of this requirement,
EPA estimates that the smallest
domestic septage haulers will most
likely find shifting to land application
less expensive than continuing to
surface dispose (EPA estimates that
larger domestic septage haulers,
however, will continue to practice
surface disposal). Compliance costs for
domestic septage haulers are estimated
per-firm or per-tankload, as outlined in
the discussions below, covering the
impacts from the part 503 regulation for
the use or disposal practice employed
by a domestic septage hauler.
As mentioned previously, the RIA
discusses both the benefits and the costs
of the part 503 regulation. The
presentation on benefits in the part 503
RIA is limited to a description of the
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9373
methodology used to estimate benefits
and a summary of the results of the
benefit analysis. More details on the
aggregate risk assessment may be
obtained from the document entitled
"Human Health Risk Assessment for the
Use and Disposal of Sewage Sludge:
Benefits of Regulation." Information on
obtaining single copies of this document
is provided in part XTV.
The risk assessment for the benefits
analysis follows the process outlined by
the National Academy of Sciences. The
assessment begins with a hazard
identification and a source assessment
and continues with fate and transport
estimates, exposure assessments,
pharmacokinetics analysis, and dose-
response assessments. These
components are used to estimate
changes in public health, measured as
morbidity and mortality.
The first step in estimating the
benefits of the final part 503 regulation
involves estimating the baseline public
health risks of sewage sludge use or
disposal. These risks are presented as
cases of cancer and other adverse health
effects, such as lead-related adverse
effects. The key inputs for estimating
baseline risks include source (POTW)
information, sewage sludge pollutants,
and ultimate use or disposal site
characteristics.
Baseline risks from sewage sludge use
or disposal practices are characterized
using (1) sewage sludge quality as
determined from the analytical portion
of the NSSS, (2) the amount of sewage
sludge used or disposed of by each
POTW, and (3) the fate and transport of
the pollutants subsequent to use or
disposal, depending on a number of
different environments that vary with
each use or disposal practice.
Using the above inputs, the analysis
estimates the potential pathways of
human exposure and models the fate
and transport of the key sewage sludge
pollutants for these pathways. The
analysis then estimates the potential
population exposed. This information,
along with dose-response data for each
of the sewage sludge pollutants of
concern, is used to characterize baseline
public health risks.
After baseline risks were estimated,
risk estimates were developed assuming
the final part 503 requirements are met.
The regulatory compliance strategies for
the public health risk analysis
assessment paralleled the strategies
used to estimate the compliance cost.
The same risk assessment process is
used to derive the change in the
baseline risk as a result of the
requirements for each part 503 use or
disposal practice. This change in the
baseline is the measure of benefit.
Estimates of the benefits for each use
or disposal practice are expressed as the
number of disease cases avoided. These
disease cases include cancer cases
avoided and noncancer human health
effects avoided. Estimated costs and
benefits for the part 503 requirements
for each part 503 use or disposal
practice are discussed later.
Land Application
Cost and benefit analyses for the part
503 land application requirements were
conducted by type of treatment works or
other entity. Results of the analyses for
secondary and advanced treatment
works, primary treatment works,
privately owned treatment works,
federally owned treatment works, and
domestic septage haulers are presented
as follows.
For secondary and advanced
treatment works, compliance with the
final part 503 regulation was
determined by comparing the sewage
sludge quality of the POTWs in the
NSSS with either pollutant
concentration limits or the cumulative
pollutant loading rate limits. For the
cumulative pollutant loading rate limits,
EPA assumed the sewage sludge
application rate for a POTW is the
application rate from the NSSS. The
Agency also assumed that an
application site has a 20-year site life
(determined to be a site life that would
impose no economic impacts to a
POTW). Results of this analysis were
extrapolated from the survey POTWs to
the entire population of secondary and
advanced treatment POTWs. The
analysis indicated that of the 4,328
secondary and advanced treatment
POTWs estimated to practice land
application, 49 POTWs, or 1 percent,
fail the ceiling concentrations. An
additional 3,216 POTWs, or 74 percent,
pass the pollutant concentration limits.
Of the remaining 1,063 POTWs, most
are able to meet the cumulative
pollutant loading rate limits. Nearly all
of these POTWs, even though they have
to meet more extensive recordkeeping
requirements, are expected to comply
with the land application requirements
with no additional compliance costs
associated with pollutant limits (i.e., the
POTWs will incur no costs to shift to an
alternative use or disposal practice or
need to change current application rates
because of the life of the application
site).
Of the 49 POTWs that fail the
pollutant ceiling limits, 30 are expected
to institute more stringent pretreatment
requirements and were estimated to
continue to practice land application.
The remaining 19 POTWs are expected
to shift to codisposal.
The total quantity of sewage sludge
that fails ceiling limits is 80,000 dmt. Of
this, 63,000 dmt is expected to be
shifted to codisposal. Costs to POTWs
for pretreatment are $2.9 million. Total
costs to POTWs for shifting to
codisposal are $6.0 million. Thus, the
costs associated with sewage sludge that
fails to meet ceiling concentrations is
estimated to be $8.9 million.
Of those POTWs whose sewage sludge
meets the ceiling limits but that does
not meet the pollutant concentration
limits, 49 POTWs are estimated to
dispose of sewage sludge that is
expected to fail to meet the cumulative
limits with existing application rates
and a 20-year site life. However, all but
two of the representative survey POTWs
were out of compliance with existing
state regulations at the time of the
NSSS. Changes made to use or disposal
practice because the POTW is out of
compliance with either existing state or
Federal requirements are not considered
a cost of part 503. Furthermore,
following discussions with one of the
two surveyed POTWs that failed the
cumulative pollutant loading rate limits,
the Agency determined that impacts on
this POTW (which represents six
nationwide) would be very small
because of the easy availability of large
amounts of additional land for
application of sewage sludge and the
ability of the POTW to shift among
various other use or disposal practices
at virtually no incremental cost.
One other POTW whose sewage
sludge is estimated to fail the part 503
land application pollutant limits
(represented by one POTW in the
survey) is expected to dispose of a
portion of the sewage sludge that is
currently land applied in a municipal
solid waste landfill, a practice employed
by another POTW operated by the same
authority. The estimated incremental
cost of shifting 1,800 dry metric tons
from land application to codisposal is
approximately $9,000 annually.
Total compliance costs for meeting all
land application pollutant limits are
estimated to be $8.9 million. The
quantity of sewage sludge shifted from
land application to codisposal is
estimated at approximately 4 percent of
the total quantity land applied.
Management practices in the land
application subpart are expected to
impose a negligible cost on secondary
and advanced treatment POTWs.
General requirements are estimated to
cost $0.2 million annually. Monitoring
costs based on the frequency of
monitoring requirements in the part 503
regulation are expected to be $1.6
million annually. Record keeping costs
are estimated to be $0.9 million
-------
9374 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
annually. Finally, reporting costs are
estimated at about $20,000 annually.
Thus, the total estimated compliance
costs associated with land application
for secondary and advanced treatment
POTWs are estimated to be $11.6
million annually.
As discussed previously, per-POTW
costs by flow rate for secondary and
advanced treatment POTWs that land
apply sewage sludge were applied to the
948 primary treatment POTWs
estimated to land apply sewage sludge.
Those per-POTW costs ranged from
$426 to $43,507 annually. Total costs for
primary treatment works that practice
land application are expected to be $1.9
million annually.
Per-POTW costs developed for the
smallest POTWs in the NSSS that land
applied sewage sludge were applied to
privately owned treatment works. An
estimated cost of $426 per treatment
works \vas applied to the 1,029 privately
owned treatment works to estimate the
cost of the part 503 land application
requirements. Total costs of the part 503
land application requirements for this
group of treatment works is estimated to
bo $0.4 million annually.
The S426 per treatment works cost for
small treatment works also was applied
to 53 Federally owned treatment works
to estimate the cost of the land
application requirements. Estimated
costs for Federally owned treatment
works using the S426 per treatment
works cost is $ 0.02 million annually.
Monitoring costs discussed above for
the different groups of treatments works
include some costs for monitoring
needed to show compliance with the
operational standards for pathogen and
vector attraction reduction in part 503.
No other costs are included for the part
503 pathogen and vector attraction
reduction requirements because of the
current requirements in 40 CFR part 257
for pathogen and vector attraction
reduction. The requirements in part 503
are either identical to current part 257
requirements (i.e., class requirements
that can include meeting PSRP) or are
similar to those current requirements in
part 257 but expressed differently (i.e.,
part 503 indicates pathogen density
requirements that must be met, but
properly operated PFRP processes,
which can be used to meet Class A
requirements, should be able to meet the
limits specified). Since the part 257
requirements currently apply, no
additional costs, aside from some
monitoring cost, for the part 503
pathogen and vector attraction
reduction requirements are expected.
Domestic septage haulers practicing
land application are required either (1)
to inject or incorporate the septage into
the soil and meet harvesting and site
access restrictions or (2) to add alkali to
raise the pH of domestic septage to 12
for 30 minutes. In addition, the annual
application rate for an application site is
limited based on the amount of nitrogen
needed by the crop or vegetation grown
on the land.
Domestic septage haulers that apply
domestic septage to agricultural land,
forest, or a reclamation site must meet
certain record keeping requirements
including noting the amount of septage
applied to each site. The only cost of the
land application requirements for
domestic septage haulers is this record
keeping cost, which is estimated at $0.2
million annually.
Based on the previous figures, the
Agency estimates that the total cost of
complying with land application
requirements in the final part 503
regulation will be $14.2 million
annually.
Baseline risks associated with land
application of sewage sludge (i.e., the
risks associated with current practices)
are estimated to be less than 1 cancer
case and about 500 cases of other health
effects. The benefits of complying with
the final part 503 regulation are
expressed as reductions in the risk—the
number of baseline cases that are
avoided. For land application, the
benefits are estimated to be less than 1
cancer case avoided and 0 to 500 cases
of other adverse health effects avoided.
Surface Disposal
The final part 503 regulation for
surface disposal of sewage sludge
requires that sewage sludge meet certain
pollutant concentrations before being
placed on an active, unlined sewage
sludge unit. The pollutant concentration
limits vary, depending on the distance
from the site to the property boundaries.
Management practices, monitoring
frequency, record keeping, and
reporting requirements also are
included in part 503 for surface disposal
of sewage sludge, regardless of whether
the site is lined or unlined. Costs and
benefits of the part 503 surface disposal
requirements on the different groups of
treatment works and other entities are
discussed as follows.
Data on quality of sewage sludge
placed on a surface disposal site were
obtained from the NSSS and compared
to the appropriate pollutant limits
presented in the surface disposal
subpart. The Agency made several
assumptions necessary to select
appropriate pollutant limits to compare
First, EPA assumed all active sewage
sludge units are located more than 150
feet from the property boundary of the
surface disposal site (a reasonable
worse-case assumption). Second, the
Agency assumed that all active sewage
sludge units are unlined (based on the
finding that no monofills in the NSSS
were reported to be lined). The part 503
pollutant limits for units located 150 ft.
or more from the property boundary
were thus determined to be the
appropriate limits for comparison with
pollutant concentrations from the NSSS.
Because of the expense of installing
ground-water monitoring wells, the
Agency determined that most POTWs
reporting in the NSSS incorporated
sewage sludge into the land for disposal
(called dedicated land application in the
NSSS) would shift to land application
rather than continue to use the land
strictly for disposal. The Agency
identified POTWs that would shift by
assuming that any POTW with an
application rate that allowed it to meet
the cumulative pollutant loading rates
in the land application subpart, while
applying the sewage sludge at an
agronomic rate, would shift to land
application. The Agency estimates that
this assumption results in no costs to
the POTWs that could meet the land
application requirements (the POTW
only has to be permitted for land
application rather than for surface
disposal). Out of 1,936 surface
disposers, 526 were estimated to' 5
permitted as land appliers. The
remaining 1,410 POTWs were estimated
to be permitted as surface disposers.
Included in this count are 301 POTWs
that store sewage sludge for more than
two years. Two additional survey
POTWs, representing 60 nationwide, are
expected to discontinue long-term
storage and codispose more of their
sewage sludge. Costs for increasing the
quantity of sewage sludge disposed
annually are estimated to be $0.4
million.
Results of the pass/fail analysis for the
1,410 surface disposers indicate that all
but eight POTWs have sewage sludge
that meets the pollutants limits. The
eight POTWs are expected to request
site-specific pollutant limits. If site-
specific pollutant limits are allowed,
sewage sludge from all of the POTWs is
expected to meet the site-specific
pollutant limits based on the difference
between the actual depth to ground
water at the active sewage sludge unit
and the depth to ground water assumed
when the part 503 pollutant limits were
developed. Thus, no surface disposers
are expected to fail pollutant limits.
Costs for meeting general
requirements will apply. These include
a requirement to provide a closure plan
when the surface disposal site closes.
Based on an assumption that one-
-------
Federal Register / Vol. 58, No. 32 /Friday, February 19, 1993 / Rules and Regulations 9375
twentieth of all surface disposal units
close each year, total costs for this
requirement are expected to be about
$30,000 annually.
Management practice costs will also
be incurred. Most of the management
practice requirements are very similar to
those in part 257 and are expected to
result in negligible costs. However,
unlined surface disposal units (which
all are assumed to be) are unlikely to be
certified that they will not contaminate
ground water. Thus, EPA assumes
ground-water monitoring must be
performed. The total cost to plan the
monitoring program, install monitoring
wells, and sample and test ground water
is expected to total $1.5 million per
year.
Pathogen and vector attraction
reduction requirements will have an
impact on surface disposers. A number
of POTWs are estimated to require
further sewage sludge processing or to
use daily cover in order to meet these
requirements. Annual costs for all these
changes are estimated at $9.6 million.
The part 503 regulation also has
frequency of monitoring, record
keeping, and reporting requirements
when sewage sludge is placed on an
active sewage sludge unit. Costs for
these activities are estimated at $0.6
million annually. Total costs for
secondary and advanced treatment
POTWs to comply with surface disposal
requirements in the final part 503
regulation are estimated at $12.1 million
annually.
The per-POTW costs for placement of
sewage sludge on a surface disposal site
developed using the NSSS were applied
to the 273 primary treatment POTWs
estimated to practice surface disposal.
These costs ranged from $3,925 to
$96,922 per POTW. Total costs for
primary treatment POTWs to meet the
surface disposal requirements in the
final part 503 regulations are estimated
to be $1.8 million annually.
A per-POTW cost of $3,925 for the
smallest POTWs in the NSSS that place
sewage sludge on an active sewage
sludge unit was used to estimate the
costs of compliance for the 551 privately
owned treatment works which place
sewage sludge on a surface disposal site.
The estimated cost of complying with
surface disposal requirements for
privately owned treatment works is $2.2
million annually.
The per-POTW cost of $3,925 for the
smallest POTWs in the NSSS that place
sewage sludge on an active sewage
sludge unit also was used to estimate
compliance costs for Federally owned
treatment works which place sewage
sludge on an active sewage sludge unit.
Multiplying that unit cost times 28
Federally owned treatment works
results in an estimated cost $110,000
annually for Federally owned treatment
works to meet the part 503 surface
disposal requirements.
Domestic septage placed on an active
sewage sludge unit must meet only the
general requirements management
practices, vector attraction reduction
requirements, monitoring requirements
(only if alkali addition is to meet vector
attraction reduction requirements), and
record keeping requirements. The
largest cost is for management practices,
which includes ground-water
monitoring. Because of this expense,
884 small domestic septage haulers are
expected to shift to land application.
Costs for ground-water monitoring are
$1.3 million, costs for the shift to land
application are $0.9 million, and costs
for record keeping and reporting are
$0.06 million. The total cost for the
1,360 domestic septage haulers that
currently place domestic septage on an
active sewage sludge unit is estimated at
$2.2 million per year, costing
approximately $981 to $2,798 per firm,
depending on the size of the firm (in
gallons per year of domestic septage
pumped). The total cost of the part 503
surface disposal requirements to all
types of treatment works and to other
entities is estimated to be $18.3 million
per year.
The baseline risks associated with
surface disposal (i.e., the risks
associated with current practice) are
estimated to be less than one cancer or
other health effects case. The benefits of
complying with the surface disposal
requirement, expressed as the number of
baseline cases that are avoided, are
estimated to be 0 to 0.07 cancer cases
avoided and less than one other health
effects avoided.
Sewage Sludge Incineration
The part 503 requirements for firing
sewage sludge in a sewage sludge
incinerator require that the allowable
concentration of selected inorganic
pollutants in the sewage sludge be
calculated using equations in the
regulation. Terms in the equation must
be determined on a case-by-case basis,
except for the risk specific
concentration for the pollutants. The
Agency developed these concentrations
using a pathway risk assessment. The
only pathway evaluated was the
inhalation pathway. For this reason, the
pollutant limits in the incineration
subpart protect public health from the
reasonably anticipated adverse effect of
the pollutants if the pollutants are
inhaled.
Also included in this subpart is an
operational standard for total
hydrocarbons (THC). The value for THC
in the final part 503 regulation can not
be exceeded in the exit gas from the
sewage sludge incinerator stack.
Management practices and frequency of
monitoring, record keeping and
reporting requirements are also
included in this subpart.
The impacts of the part 503
incineration requirements on secondary
and advanced treatment POTWs and
primary treatment POTWs are
investigated in this part of the preamble
because only those groups of treatment
works are believed to operate sewage
sludge incinerators. However, other
treatment works (both privately owned
and publicly owned) transfer sewage
sludge to POTWs that operate sewage
sludge incinerators. Since costs of the
incinerator subpart are based on costs to
POTWs operating sewage sludge
incinerators, cost-passthrough
associated with sewage sludge
transferred to treatment works operating
sewage sludge incinerators is discussed
in the regulatory flexibility analysis to
avoid double counting of total cost.
A pass/fail analysis was conducted on
the NSSS POTWs using the site-specific
information necessary to calculate
whether, with existing sewage sludge
quality, the risk-specific concentrations
in the incineration subpart could be met
without any changes in feed rate,
dispersion factor, or incinerator control
efficiencies. Results of this analysis
were extrapolated to the entire
population of POTWs that operate
sewage sludge incinerators nationally
(these numbers are based on the
analytical survey weights).
Of 185 POTWs that operate 284
sewage sludge incinerators, 171 can
meet the part 503 requirements for
inorganic pollutants, and all can meet
the THC operational standard. Of those
failing the limits on inorganic pollutants
(14 POTWs), all were assumed to retrofit
wet electrostatic precipitators (WESPs).
When added to the existing pollution
control equipment, WESPs result in
pollutant control efficiencies needed
without changing the existing sewage
sludge quality or dispersion factor (i.e.,
raising stack height) and without
reducing sewage sludge feed rates. The
cost of retrofitting and operating WESPs
is estimated to be $3.6 million annually.
No cost of complying with the THC
operational standard will be incurred.
Costs to test a sewage sludge
incinerator for pollutant control
efficiencies, costs to develop a
dispersion factor, and management
practice costs, which include costs to
install and operate different equipment,
are estimated at $7.3 million annually.
Frequency of monitoring, record
-------
9376 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
keeping and reporting costs are
estimated to total $0.3 million annually.
Total estimated costs to comply with the
part 503 requirements for firing sewage
sludge in a sewage sludge incinerator
for secondary and advanced treatment
POTWs are $11.2 annually.
Estimated costs to comply with the
part 503 incineration requirements for
the NSSS POTWs range from $37,000 to
$315,000 perPOTW. If these costs are
applied to the 11 primary treatment
POTVVs estimated to operate sewage
sludge incinerators, the estimated cost
of complying with the part 503
incineration requirements is $0.5
million annually for primary treatment
POTWs, Total costs for secondary and
advanced treatment works and for
primary treatment works to comply with
the part 503 incinerator requirements is
$11.7 million annually.
Baseline risks associated with
incineration (i.e., current practice risks)
of sewage sludge are estimated to be 0.3
to 4 cancer cases and 100 other health
offocls. The benefits of complying with
the part 503 incineration requirements
ore expressed as reductions in number
of baseline cases avoided. For sewage
sludge incineration, the benefits are
estimated to be 0.09 cancer cases
avoided and 90 other adverse health
effects avoided.
A few additional costs of part 503 are
not associated with the part 503 use or
disposal practice employed. These costs
are associated with (1) reading and
interpreting the final part 503
regulation, which are assumed to be
incurred whether a part 503 use or
disposal practice is used for the use or
disposal of sewage sludge, and (2)
obtaining copies of part 258 permits,
which are assumed to be needed to
show that the municipal solid waste
landfill meets the part 258
requirements. Costs of these activities
are estimated to be $1.7 million per
year.
The final part 503 regulation is
expected to result in environmental
benefits other than the benefits
associated with reducing the incidence
of adverse human health effects. These
environmental benefits are an outgrowth
of the general reduction in the amount
and toxicity of sewage sludge used or
disposed in ways that damage the
environment, particularly sewage sludge
that is placed in environmentally
sensitive areas. These environmental
benefits consist mainly of improved
habitats for wildlife and other species in
the areas where incineration of sewage
sludge occurs.
For example, emissions reductions in
the vicinities of sewage sludge
incinerators may reduce particulate and
other types of deposits on buildings,
automobiles, and structures, reducing
the extent to which these items are
damaged by air pollution. Commercial
farms and home gardens located in areas
affected by deposits from sewage sludge
incinerators may experience some
increase in crop vitality because of
lower levels of discharged pollutants.
The regulation may account for some
cost savings as well. Many POTWs
whose sewage sludge meets the
pollutant concentration limits are
currently practicing disposal (e.g.,
incineration, codisposal). EPA believes
that part 503 regulation may help to
ease misapprehensions about the quality
of sewage sludge and that a more
receptive market for high-quality sewage
sludge now being disposed might
develop. If the regulation helps to
encourage the shift from disposal to
land application for just 10 percent of
all high-quality sewage sludge now
disposed, a savings of nearly $1 million
in fertilizer costs might be realized by
farmers.
Regulatory Flexibility Analysis
The Regulatory Flexibility Act
requires all Federal agencies to analyze
the impact of a regulation on small
businesses, small governmental
jurisdictions, and small organizations.
The purpose of this analysis is to
determine the extent to which the
regulation has an impact on small
entities and the nature of those impacts.
For the purpose of the final part 503
regulation, the Agency defines a small
entity as a POTW with a flow rate equal
to or less than one MGD that
corresponds to a service area of
approximately 10,000 residents; a
privately owned treatment works
(nearly all of which have a flow rate of
one MGD or less); and all domestic
septage haulers, regardless of size (most
domestic septage firms are operated by
one self-employed person and possibly
another part-time or full time
employee).
Approximately 90 percent of all
entities potentially subject to the final
part 503 regulation are considered small
by this definition. However, only a
portion of small entities employ use or
disposal practices covered by the part
503 regulation. Only about 40 percent of
all small entities potentially subject to
the part 503 regulation employ a use or
disposal practice covered by part 503.
The total estimated compliance costs
for the final part 503 regulation for
small entities is $14.1 million, the
majority of which is attributed to land
application and surface disposal of
sewage sludge. Of the total estimated
costs for all small entities, 73 percent is
attributed to entities (treatment works
and septage haulers) that place sewage
sludge on a surface disposal site.
Estimated compliance costs for the
part 503 regulation for small publicly
and privately owned treatment works
are $11.0 million for direct and indirect
costs including $0.4 million for cost of
reading and interpreting the regulation.
Thus, compliance costs for small
treatment works are only about 23
percent of the total estimated
compliance costs for all treatment works
and firms. EPA has judged that small
privately or publicly owned treatment
works are not subject to substantial
compliance costs under part 503 and
thus focused attention on domestic
septage haulers, some of which bear the
largest portion of compliance costs as a
ratio of revenue among small entities.
Domestic septage haulers will incur
$2.4 million in compliance costs to meet
the requirements in part 503. Domestic
septage haulers that practice land
application or surface disposal (6,120
businesses) handle about 3.1 billion
gallons of domestic septage annually.
Prices charged on average for domestic
septage pumping are approximately $70
per 1,000-gallon septic tank. Total
annual revenues for this group are thus
estimated to be $217 million annually.
The incremental costs of this regulation
are thus only about 1 percent of the total
annual revenues for this group of
businesses. Total operating costs are
calculated to be approximately $156.6
million for land appliers and $44.7 for
surface disposers. The annual costs of
complying with the part 503 regulation
($0.2 million for land appliers and $2.2
million for surface disposers) are
therefore estimated to increase operating
costs by about 1 percent. Only the
smallest surface-disposing domestic
septage haulers are considered to be
potentially affected significantly by the
part 503 regulation (compliance cost as
a percentage of revenues are expected to
be 14 percent for these firms. Most small
entities are associated with ratios of one
percent or less).
The Agency is not requiring domestic
septage haulers to meet the more
stringent and costly pathogen and vector
requirements for POTWs and privately
owned treatment works. Domestic
septage haulers are exempted from
testing domestic septage for inorganic
and organic pollutants, a major cost
item for POTWs and privately owned
treatment works. Record keeping
requirements also have been kept as
simple as possible, and no reporting is
required. Thus, EPA believes it has
provided domestic septage haulers with
the least burdensome regulation
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9377
compatible with its mandate to protect
public health and the environment.
Prices charged by domestic septage
pumpers vary widely by region. These
prices range from $35 per septic tank to
more than $200 per septic tank. If costs
to comply with the part 503
requirements are passed directly
through to the estimated 4.3 million
homeowners who have a septic tank
pumped in any one year, the pumping
costs could rise by about $1.30 each.
This is an increase of 0.7 percent to 4
percent (averaging 2 percent) over
current prices for tank pumping. Even if
prices increase to an average of $71.30,
or about $36 per year per household
(based on a tank pumping schedule of
every two years), this is considerably
less, on average, than typical per-
household charges for sewage treatment
at POTWs.
Domestic septage haulers that practice
land application are estimated to incur
$0,2 million annually to comply with
part 503 requirements. All of these costs
are associated with meeting the record
keeping requirements. Small surface
disposers, on the other hand, are
expected to shift to land application and
larger domestic septage haulers are
expected to install ground-water
monitoring wells and meet other
requirements of subpart C. The major
costs to these firms to shift practices are
the costs to monitor ground water or to
acquire additional land. The major cost
to continue to surface dispose is the cost
to install wells and monitor ground
water. The cost to shift to land
application and to monitor ground
water account for nearly 97 percent of
all costs to surface-disposing domestic
septage haulers. Average incremental
costs per firm are $48 for land appliers
and $1,602 for surface disposers. Based
on an analysis of net present value for
the most affected small surface
disposing septage haulers, EPA
concludes that septage hauling firms are
unlikely to close because of part 503
requirements.
Paperwork Reduction Act
The annual public reporting burden
for the collection of information
imposed by this final rule, averaged
over a 3-year period, is estimated to be
133,198 hours for 11,056 respondents
(5,088 publicly owned treatment works,
1,208 privately owned treatment works,
and 4,768 domestic septage haulers)
practicing land application; 65,295
hours for the 6,188 respondents (2,071
publicly owned treatment works, 547
privately owned treatment works, and
3,570 domestic septage haulers)
disposing of sewage sludge on surface
disposal sites; and 207,294 hours for the
186 respondents (publicly owned
treatment works) which fire sewage
sludge in a sewage sludge incinerator.
The average time per response per
respondent is estimated to be 36.4
hours. Respondent reporting and
recordkeeping burden for this collection
of information includes time for
reviewing instructions, searching
existing data sources, gathering and
maintaining the data needed, and
completing and revising the collection
of information.
The information collection
requirements in this rule have been
approved by the Office of Management
and Budget (OMB) under the Paperwork
Reduction Act, 44 U.S.C. 3501 et seq.
and have been assigned control number
2040-0157.
Send comments regarding the burden
estimate or any other aspect of this
collection of information, including
suggestions for reducing this burden to
Chief, Information Policy Branch, EPA,
401 M Street, SW. (PM-223Y),
Washington, DC 20460; and to the
Office of Information and Regulatory
Affairs, Office of Management and
Budget, Washington, DC 20503, marked
"Attention: Desk Officer for EPA."
Part XIV: Availability of Technical
Information on the Final Rule
Availability of the Final Rule and
Preamble
The final rule and preamble may be
obtained by contacting: Dr. Alan Rubin,
Sludge Risk Assessment Branch (WH-
586), United States Environmental
Protection Agency, 401 M Street, SW,
Washington, DC 20460, (202) 260-1306.
Availability of Technical Support
Documents
The following technical support
documents are available:
(1) Technical Support Document for
Land Application of Sewage Sludge—
Volume I—PB93-110575
(2) Technical Support Document for
Land Application of Sewage Sludge—
Volume II—-PB93-110583
(3) Technical Support Document for
Surface Disposal of Sewage Sludge—
PB93-110591
(4) Technical Support Document for
Incineration of Sewage Sludge—
PB93-110617
(5) Technical Support Document for
Pathogen and Vector Attraction
Reduction in Sewage Sludge—PB93-
110609
(6) Human Health Risk Assessment for
Use and Disposal of Sewage Sludge:
Benefits of Regulation—PB93-111540
(7) The Regulatory Impact Analysis—
PB93-110625
These documents may be ordered
from: National Technical Information
Service, 5285 Port Royal Road,
Springfield, Virginia 22161, ATTN:
Sales, Telephone No. (703) 487-4650.
Please specify PB number when
ordering.
Availability of Data and Information on
the National Sewage Sludge Survey
Data and information from the
National Sewage Sludge Survey are
available as computer files and printed
documents. These items can also be
ordered from the National Technical
Information Service (NTIS), 5285 Port
Royal Road, Springfield, Virginia 22161,
ATTN: Sales, telephone number (703)
487-4650. Please specify PB number
when ordering.
Computer files of the database for the
National Sewage Sludge Survey are
available in three different formats.
Persons requesting computer files,
under any option, will want the
National Sewage Sludge Survey: Data
Element Dictionary for the
Questionnaire and Analytical Databases
(PB90-198961) and they may want the
Data Element Dictionary for the Data
Conventions Database (PB93-500403).
These dictionaries contain definitions
and specifications for all variables in
each referenced database. The three
computer file formats are as follows:
(1) ASCII Format Databases for the
1988 National Sewage Sludge Survey
(PB93-500403) are available. These are
IBM PC compatible files containing the
Questionnaire Database, the Analytical
Database, and the Data Conventions
Database for the National Sewage
Sludge Survey. These databases come
on fourteen 3.5" 1.44 Mb floppy
diskettes and approximately 20 Mb of
hard drive space is required for
installation.
(2) SAS format tapes (PB-90-501834)
are also available. Databases available in
this format include the Questionnaire
Database and the Analytical Database.
These are nine track tapes, written in
SAS transportable code at 1600 bpi,
with logical record lengths of 80 and
block sizes of 8000. The tapes were
written under the OS operating system,
but they should also be readable by
CMS, VSE, AOS/VS, PRIMOS, and
VMS.
(3) Computer access to the EPA
National Computer Center (NCC), which
houses the reference copy of the
database in the format of the SAS
system for statistical analysis, is
available on a fee for service basis. In
order to open an account with NTIS on
the NCC system, state that you wish to
access the database for the National
Sewage Sludge Survey. No special
-------
9378 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
passwords are required and the dataset
identifiers are listed in the appropriate
data element dictionaries.
Printed copies of the Analytical
Database (PB90-107491), and
Questionnaire Database (PB90-107509)
ore also available from NTIS.
Availability of Other Documents Used
in Developing the Final Part 503 Rule
A copy of the documents (e.g.,
Response to Comments Document for
the proposed part 503 Rule, Analytical
Methods for the National Sewage Sludge
Survey, Statistical Support
Documentation for part 503, etc.) cited
in the reference section of this Notice
are available for review at EPA's Water
Docket; 401M Street, SW; Washington,
DC 20460. The Docket is located in
room L-102. For access to Docket
materials, call (202) 260-3027 between
9 a.m. and 3:30 p.m. for an
appointment. The EPA public
information regulation (40 CFR part 2)
provides that a reasonable fee may be
charged for copying.
List of References Used in Preamble
1. Abron-Robinson, L.A. and L.VV.
Wolnborgor. 1984. Sewage Sludge Versus
Commercial Methods for Reclaiming
Strip Mine Soil. U.S. EPA, Municipal
Environmental Research Laboratory and
Poor Consultants. Cincinnati, OH. EPA/
600/2-84/155.
2. American Petroleum Institute (API). 1983.
Land Treatment Practices in the
Petroleum Industry. Environmental
Research and Technology, Inc., Concord,
MA.
3. Anthony, R.G. and G.W. Wood. 1979.
Effects of Municipal Wastewater
Irrigation on Wildlife and Wildlife
Habitat. Pp. 213-223. In: Sopper,
William E. and Sonja N. Kerr. 1979.
Utilization of Municipal Sewage
Effluents and Sludge on Forest and
Disturbed Land. Pennsylvania State
University Press, University Park, PA.
4. Association for Utilization of Sewage
Sludge. 1988. Proceedings-Second
International Symposium on Land
Application of Sewage Sludge. Tokyo,
Japan.
S. Baxter, H.C., M. Aquiler, and K. Brown.
1983. Heavy Metals and Persistent
Organlcs at a Sewage Sludge Disposal
Site. J. Environ. Qual. 12(3):311-316.
0. Baxter, J.C, D.E. Johnson, and E.W.
Kienholz, 1980. Uptake of Trace Metals
and Persistent Organics Into Bovine
Tissues from Sewage Sludge—Denver
Project, pp. 285-309. In G. Bittion, B.L.
Damron, G.T. Edds, and J.M. Davidson
(cds.) Sludge—Health Risks of Land
Application. Ann Arbor Science Publ.
Inc., Ann Arbor, MI.
7. Brown, D.S., and J.D. Allison. 1987.
MINTEQAI, An Equilibrium Metal
Spoclatlon Model: User's Manual. U.S.
Environmental Research Laboratory,
Athens, GA. EPA/600/3-87-012.
8. Brown, R.E. 1975. Significance of Trace
Metals and Nitrates in Sludge Soils. J.
Water Pollut. Control Fed. 47:2863-2875.
9. CAST (Council for Agricultural Science
and Technology). 1976. Application of
Sewage Sludge to Cropland: Appraisal of
Potential Hazards of the Heavy Metals to
Plants and Animals. EPA 430/9-76-013.
10. Chaney, R.L. 1973. Crop and Food Chain
Effects of Toxic Elements in Sludges and
Effluents. Pp. 129-141. In: Proc. of the
Joint Conf. on Recycling Municipal
Sludges and Effluents on Land,
Champaign, IL. (July 9-13,1973).
National Assoc. State Univ. and Land
Grant Colleges, Washington, D.C.
11. Chaney, R.L., R.J.F. Bruins, D.E. Baker,
R.F. Horcak, J.E. Smith Jr., and D.W.
Cole. 1987. Transfer of Sludge-Applied
Trace Elements to the Food-Chain. Pp.
67-99. In: A.L. Page, T.J. Logan and J.A.
Ryan (eds.). Land Application of
Sludge—Food Chain Implications. Lewis
Publishers, Inc. Chelsea, MI.
12. Chang, A.C. and A.L. Page. 1985. Personal
Communication. Dept. of Soil and
Environmental Sciences, Univ. of
California, Riverside, CA. (As cited in
Page, A.L., T.G. Logan, J.A. Ryan. 1987.)
13. Cohen, A. Clifford, Jr. 1959. "Simplified
Estimators for the Normal Distribution
When Samples are Singly Censored or
Truncated." Technometrics. Vol. 1, No. 3
(August). 217-237.
14. Cole, D.W. 1980. Response of Forest
Ecosystems to Sludge and Wastewater
Applications—A Case Study in Western
Washington. In: U.S. EPA. 1980.
Utilization of Municipal Wastewater and
Sludge for Land Reclamation and
Biomass Production. Washington, D.C.
EPA 430/9-81-012.
15. Cools, A., et al. 1976. Biochemical
Response of Male Volunteers Ingesting
Inorganic Lead for 49 Days. Int. Arch.
Occup. Environ. Health 38:129-139.
16. Delos, C.G., et al. 1984. Toxic Substances.
Technical Guidance Manual for
Performing Waste Load Allocations,
Book H-Streams and Rivers, Toxic
Substances. U.S. EPA, Office of Water
Regulations and Standards, Washington,
D.C. EPA-440/4-84-022.
17. Dowdy, R.H., and W.E. Larson. 1975. The
Availability of Sludge-Borne Metals to
Various Vegetable Crops. J. Environ.
Qual. 4:278-282.
18. Dowdy, R.H., et al. 1978. Growth and
Metal Uptake of Snap Beans Grown on
Sewage Sludge—Amended Soils, a Four-
Year Field Study. J. Environ. Qual.
7:252-257.
19. Drees, L.M. 1988. Effect of Lime and
Other Precipitants or Sludge
Conditioners on Conversion of
Chromium to the Hexavalent State When
Sludge is Incinerated. Final Report. EPA
Contract 68-03-3346.
20. Felmy, A.R., D.C. Girvin, and E.A. Jenne.
1984. MINTEQ—A Computer Program
for Calculating Aqueous Geochemical
Equilibrium. EPA-600/3-84-032.
21. Fries, G.F. 1989. Potential
Polychlorinated Biphenyl Residues in
Animal Products firam Application of
Contaminated Sewage Sludge to Land. J.
Environ. Qual. 11:14-20.
22. Fries, G.G., G.S. Marrow and C.H.
Gordon. 1973. Long-Term Studies of
Residues in Animal Products from
Application of Contaminated Sewage
Sludge to Land. J. Environ. Qual.
23. Genstle, R.W., and D.M. Albrinck. 1982.
Atmospheric Emissions of Metals from
Sewage Sludge Incineration. Air Poll.
Control Assoc. 32(11) (November).
24. Gilliom, Robert J. and D.R. Helsel. 1986.
"Estimation of Distributional Parameters
for Censored Trace Level Water Quality
Data. 2. Verification and Applications."
Water Resources Research. Vol. 22, No.
2. (February). 135-146.
25. Goring, C.A.I., and J.W. Hanaker. 1972.
Organic Chemicals in the Soil
Environment. Vol. 1. Marcel Dekker,
Inc., N.Y.
26. Guenzi, W.D., et al. (ed.). 1974. Pesticides
in Soil and Water. (Listed. Soil Sci. Soc.
Amer., Madison, WI.)
27. Haghiri, F. 1974. Plant Uptake of
Cadmium as Influenced by Cation
Exchange Capacity, Organic Matter,
Zinc, and Soil Temperature. J. Environ.
Qual. 3:180-183.
28. Hajjar, L.M. 1985. Effect of Soil pH and
the Residual Effect of Sludge Loading
Rate on the Heavy Metal Content of
Tobacco and Peanut and the Effect of Cd
SO4 on the Cd Content of Various
Cultivars of Grass. M.S. Thesis, North
Carolina State U., Raleigh. (As Cited in:
Page, A.L., T.H. Logan, and J.A. Ryan,
1987.)
29. Hallden, J.A., C.J. Pederson, and J.P. St.
John. 1987. Steele Brook Pilot Study for
Implementing EPA's Toxic Control
Policy. Phase II Technical Analysis. U.S.
EPA, Office of Water Regulations and
Standards, Washington, D.C,
30. Hanson, K.G. and T.D. Hinesly. 1981.
Cadmium and Soil Amended with
Sewage Sludge: Effects of Residues in
Swine. Environ. Health Perspect. 28:51-
57.
31. Helsel, Dennis R., and R.J. Gilliom. 1986.
"Estimation of Distributional Parameters
for Censored Trace Level Water Quality
Data. 2. Verification and Applications."
Water Resources Research. Vol. 22, No.
2. (February). 147-155.
32. Helsel, D.R. and T.A. Cohn. 1988.
"Estimation of Descriptive Statistics for
Multi-Censored Water Quality Data."
Water Resources Research. Vol. 24, No.
12. (December). 1997-2004.
33. Hinesly, T.D., L.G. Hanson, D.J. Bray and
K.E. Redborg, 1985. Transfer of Sludge-
Borne Cadmium Through Plants to
Chickens. J. Agr. Food Chem. 33:173-
180.
34. Hinesly, T.D., E.L. Ziegler, J.J. Tyler.
1976. Selected Chemical Elements in
Tissues of Pheasants Fed Corn Grain
from Sewage Sludge-Amended Soil.
Agro/Ecosystems. 3:11-26.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9379
35. Holmgren, G. 1985. Personal
Communication to Randy Bruins, U.S.
EPA. Office of Research and
Development. Cincinnati, OH.
36. Honeyman, B.D., and P.H. Santschi. 1988.
Metals in Aquatic Systems. Environ. Sci.
Technol. 22:862.
37. Hyde, H.C., et al. 1979. Effect of Heavy
Metals in Sludge on Agricultural Crops.
J. Water Pollut. Control Fed. 51:2475-
2486.
38. HydroQual, Inc. 1986. Technical
Guidance Manual for Performing Waste
Load Allocations, Book IV: Lakes,
Reservoirs and Impoundments. Toxic
Substances Impact. U.S. EPA, Office of
Water Regulations and Standards,
Washington, D.C. EPA-440/4-87-O02.
38a. Kaitz, E.F. 1978. Home Gardening
National Report. 1975-1977. Presented at
the American Seed Trade Association,
Inc., 95th Annual Convention. Kansas
City, Missouri. June 1978.
39. LaGoy, P.K. 1987. Estimated Soil
Ingestion Rates for Use in Risk
Assessment. Risk Analysis 7:355.
40. Majima, T., et al. 1977. Studies of
Pyrolysis Process of Sewage Sludge. Pp.
381-396. In: Prog. Wat. Tech. (Vol. 9).
Pergaman Press, Great Britain.
41. National Center for Health Statistics.
1981. Plan and Operation of the Second
National Health and Nutrition
Examination Survey (1976-1980). Vital
and Health Statistics Series 1(15).
42. National Well Water Association. 1985.
DRASTIC: A Standardized System for
Evaluating Ground Water Pollution
Potential Using Hydrogeologic Settings.
Ada, OK.
43. O'Connor, G.A., et al. 1989. Plant Uptake
of Sludge Borne PCBs. J. Environ. Qual.
44. Page, A.L., T.G. Logan, and J.A. Ryan.
1987. Land Application of Sludge. Lewis
Publishers, Inc., Chelsea, MI.
45. PEI Associates, Inc. 1987. Sewer Sludge
Incineration: ISCLT Model Sensitivity
Analysis. U.S. EPA, Office of Water
Regulations and Standards, Washington,
D.C.
46. Pennington, J.A.T. 1983. Revision of the
Total Diet Study Food Lists and Diets. J.
Am. Diet. Assoc. 82:166-173.
47. Peterson, M.S., L.W. Lion, and C.A.
Shoemaker. 1988. Influence of Vapor-
Phase Sorption and Diffusion on the Fate
of Trichloroethylene in an Unsaturated
Aquifer System. Environ. Sci. Technol.
22:571.
48. Pirkle, J.L., et al. 1985. The Relationship
Between Blood Lead Levels and Blood
Pressure and Its Cardiovascular Risk
Implications. Amer. J. Epidemiol. 121(2).
49. Seaker, Eileen M., and W.E. Sopper.
Reclamation of Bituminous Strip-mine
Spoil Banks with Municipal Sewage
Sludge. Reclamation and Revegetation
Research. 3:87-100 (As cited in Seaker,
Eileen M. 1985. Uses of Philadelphia
Mine Mix for Strip-mine Reclamation in
Western Pennsylvania. City of
Philadelphia Water Department,
Philadelphia, PA.)
50. Sherlock, J., et al. 1982. Assessment of
Lead Intakes and Dose-Response for a
Population in Ayr Exposed to a
Plumbsolvent Water Supply. Hum.
Toxicol. 1:115-122.
51. Singh, D. 1983. The Effect of Land
Application of Sludge on Concentrations
of Certain Sludge-Associated Toxic
Chemicals in Michigan Soils and Crops
(Report). MI Dept. of Ag., Toxic
Substances Division, Lansing, MI.
52. Sopper, William E., and Sonja N. Kerr.
1980. Mine Land Reclamation with
Municipal Sludge—Pennsylvania's
Demonstration Program. (As cited in
Cole, 1980. pp. 55-87.)
53. Strek, H.J. and J.B. Weber. 1980.
Absorption and Translocation of
Polychlorinated Biphenyls. Proc. South
Weed, Sci, Soc. 33:226-232.
54. Taylor, D. 1988. Results of PCB Research
Conducted by Madison Metropolitan
Sewerage District (Madison, WI).
Personal Communication to Alan Rubin.
U.S. EPA. Office of Water. Washington,
D.C.
55. Touchton, J.T., et al. 1976. Residual Effect
of Liquid Sludge on Coastal Bermuda
Grass and Soil Chemical Properties. J.
Environ. Qual. 5:161-164.
56. U.S. DA. 1972. Food Consumption:
Households in the United States,
Seasons and Year 1965-1966.
Nationwide Food Consumption Survey
1965-1966, Report No. 12.
57. U.S. DA. 1982. Food Consumption:
Households in the United States,
Seasons and Year 1975-1978.
Nationwide Food Consumption Survey
1975-1978, Report No. H-6.
58. U.S. DA. 1989. Peer Review—Standards
for the Disposal of Sewage Sludge U.S.
EPA Proposed Rule 40 CFR Parts 257
and 503.
59. U.S. EPA. 1979. Process Design Manual
for Sludge Treatment and Disposal. EPA
625/1-79-011.
60. U.S. EPA. 1982. Fate of Priority
Pollutants in Publicly-Owned Treatment
Works. Vol. I. Effluent Guidelines
Division, Washington, D.C. EPA 440/1-
82-303.
61. U.S. EPA. 1983. Process Design Manual
for the Land Application of Municipal
Sludge. Municipal Environmental
Research Laboratory, Cincinnati, OH.
EPA-625/1-83-O16.
62. U.S. EPA. 1983. The Record of
Proceedings on the OWRS Municipal
Sewage Sludge Committees. Washington,
D.C.
63. U.S. EPA. 1984. Environmental
Regulations and Technology. Use and
Disposal of Municipal Wastewater
Sludge. Washington, D.C.
64. U.S. EPA. 1984. Ground-Water Protection
Strategy. Washington, DC.
65. U.S. EPA. 1985. Chromium Emissions
from Sewage Sludge Incinerators. Office
of Air and Radiation, Emission
Standards and Engineering Division.
66. U.S. EPA. 1985. Chromium Screening
Study Test Report, Sewage Sludge
Incinerator No. 13, Detroit Water and
Sewer Department, Detroit Michigan.
Office of Air Quality Planning and
Standards. EMB Report 85-CHM-5.
67. U.S. EPA. 1985. Environmental Profiles
and Hazard Indices for Constituents of
Municipal Sludge. Washington, DC.
68. U.S. EPA. 1985. Environmental Science
and Engineering. Exposure to Airborne
Contaminants Released from Land
Disposal Facilities—A Proposed
Methodology.
69. U.S. EPA. 1985. Guideline for
Determination of Good Engineering
Practice Stack Height. EPA-450/4-80-
023R.
70. U.S. EPA. 1986. Air Quality Criteria for
Lead (volumes I-IV). Environmental
Criteria and Assessment Office, Research
Triangle Park, NC. EPA-600/8-83/028aF.
71. U.S. EPA. 1986. Development of Risk
Assessment Methodology for Municipal
Sludge Incineration. Environmental
Criteria and Assessment Office,
Cincinnati, OH. ECAO-CIN-486.
72. U.S. EPA. 1986. Development of Risk
Assessment Methodology for Municipal
Sludge Landfilling. Environmental
Criteria and Assessment Office,
Cincinnati, OH. ECAO-CIN-485.
73. U.S. EPA. 1986. Development of a
Qualitative Pathogen Risk Assessment
Methodology for Municipal Sludge
Landfilling. Environmental Criteria and
Assessment Office, Office of Research
and Development, Washington, DC.
74. U.S. EPA. 1986. Guideline on Air Quality
Models (revised). Office of Air Quality
Planning and Standards, Research
Triangle Park, NC. EPA-450/2-18-O27R.
75. U.S. EPA. 1986. Reducing Lead in
Drinking Water: A Benefits Analysis
(draft final report). Office of Policy,
Planning, and Evaluation.
76. U.S. EPA. 1986. Sludge Incinerator Air
Quality Modeling. Office of Air Quality
Planning and Standards, Research
Triangle Park, NC.
77. U.S. EPA. 1986. Chromium Emissions
from a Sewage Sludge Incinerator, (Draft
Report). EPA Contract No. 68-03-3346.
78. U.S. EPA. 1987. Descriptive Statistics on
Contaminants in Municipal Sludge
Based on the EPA 40-POTW Study.
Science Applications International
Corporation. EPA Contract No. 68-01-
6912.
79. U.S. EPA. 1987. Development of Risk
Assessment Methodology for Land
Application and Distribution and
Marketing of Municipal Sludge. Office of
Health and Environmental Assessment,
Environmental Criteria and Assessment
Office, Cincinnati, OH. ECAO-CIN-489.
80. U.S. EPA. 1987. Integrated Risk
Information System Supportive
Documentation, volume I. Office of
Health and Environmental Assessment,
Washington, DC. EPA/600/8-86/032a.
-------
9380 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
81, U.S. EPA. 1987. Review of Technical
Documents Supporting Proposed
Revisions to EPA Regulations for the
Disposal/Rouse of Sewage Sludge under
section 405(d) of the Clean Water Act.
Science Advisory Board, Environmental
Engineering Committee, Washington,
D.C. SAB-EEC-87-015.
82. U.S. EPA. 1987. Task Report: Cyanide
Levels in Municipal Sewage Sludge In:
U.S. EPA. Water Engineering Research
Laboratory Monthly Report. Office of
Research and Development. Cincinnati,
OH.
83, U.S. EPA. 1987. The Effects of Municipal
Wastewater Sludge on Leachates and Gas
Production from Sludge-Refuse Landfills
and Sludge Monofllls. Water Engineering
Research Laboratory, Office of Research
and Development. Cincinnati, OH.
84. US. EPA. 1988. Analytical Methods for
the National Sewage Sludge Survey.
Washington, D.C.
85. U.S. EPA. 1988. Guidance for Writing
Caso-by-Casa Permit Requirements for
Municipal Sewage Sludge. Draft. Office
of Water Experiment. Permits Division.
86. U.S. EPA. 1988. Guidelines for Ground-
Water Classification Under the EPA
Ground-Water Protection Strategy.
Washington, D.C.
87. U.S. EPA. 1988. Location Restrictions
(Subpart B) Criteria for Municipal Solid
Waste Landfills (40 CFR Part 258)—
Subtitle D of the Resource Conservation
and Recovery Act (RCRA). Office of
Solid Waste. Washington, D.C.
88. U.S. EPA. 1988. Operating Criteria
(Subpart O—Criteria for Municipal Solid
Waste Landfills (40 CFR part 258)—
Subtitle D of the Resource Conservation
and Recovery Act (RCRA). Office of
Solid Waste. Washington, D.C.
89. U.S. EPA. 1988. Personal Communication
of B.P. Grumpier with Shireo Co., Dallas,
TX., April 6,1988.
90. U.S. EPA. 1988. POTW Sludge Sampling
and Analysis Document (Draft).
Washington, D.C.
91. U.S. EPA. 1988. Probabilistic Ground-
Water Classification at the Forty-Six
Currently Active Sewage Sludge
Monofills. Washington, D.C.
92. U.S. EPA. 1988. Review of the National
Ambient Air Qualify Standards for Lead:
Exposure Analysis Methodology and
Validation (Draft). Washington, D.C.
93. U.S. EPA. 1988. Sampling Procedures and
Protocols for the National Sewage Sludge
Survey. Washington, D.C.
94. U.S. EPA. 1988. Supporting Statement for
the National Sewage Sludge Survey.
Washington, D.C.
95. U.S. EPA. 1989. Burning of Hazardous
Waste in Boilers and Industrial Furnaces
(40 CFR Part 260)—Subtitle C of the
Resource Conservation and Recovery Act
(RCRA). Washington, D.C.
98. U.S. EPA. 1989. Interim Final Guidance
for Soil Ingostion Rates. Office of Solid
Waste and Emergency Response.
Washington, D.C. (January), Directive
Number 9850.4.
97. U.S. EPA. 1989. Review of Proposed
Sewage Sludge Incineration Rules (40
CFR Part 257 and 503). EPA-SAB-EEG-
89-035.
98. U.S. EPA. 1989a. Risk of Unsaturated/
Saturated Transport and Transformation
Interactions for Chemical Concentrations
(RUSTIC), Volume 1: Theory and Code
Verification. Office of Research and
Development, Environmental Research
Laboratory, Athens, GA. EPA Contract
No. 68-03-6304.
99. U.S. EPA. 1989b. RUSTIC
Documentation, Volume II: User's Guide.
Office of Research and Development,
Environmental Research Laboratory,
Athens, GA. EPA Contract No. 68-03-
6304.
100. U.S. EPA. 1989. Technical Support
Document: Incineration of Sewage
Sludge (Proposal). Office of Water.
101. U.S. EPA. 1989. Technical Support
Document: Land Application and
Distribution and Marketing of Sewage
Sludge (Proposal). Office of Water
Regulations and Standards, Washington,
D.C.
102. U.S. EPA. 1989. Technical Support
Document: Landfilling of Sewage Sludge
(Proposal). Washington, D.C.
103. U.S. EPA. 1989. Technical Support
Document: Pathogens and Vectors.
(Proposal). Office of Water Regulations
and Standards. Washington, D.C.
104. U.S. EPA. 1989. Technical Support
Document: Surface Disposal of Sewage
Sludge (Proposal). Office of Water
Regulations and Standards. Washington,
D.C.
105. U.S. EPA. 1990. Guidance Document for
Testing and Permitting Sewage Sludge
Incinerators. EPA Contract No. 68-03-
3533.
106. U.S. EPA. 1990. Standards for Owners
and Operators of Hazardous Waste
Incinerators (40 CFR Part 260, 261, 264
and 270)—Subtitle C of the Resource
Conservation and Recovery Act (RCRA).
Washington, D.C.
107. U.S. EPA. 1990. Supplemental Guidance
on the Development and Implementation
of Local Discharge Limitations Under the
Pretreatment Program (Draft). Office of
Water. Washington, D.C.
108. U.S. EPA. 1991. Memorandum of James
A. Ryan to Alan Rubin Committee Report
on 503 Regulations. Washington, D.C.
March 28,1991.
109. U.S. EPA. 1992. Response to Public
Comments on the Proposed Part 503
Sewage Sludge Use and Disposal
Regulations and the National Sewage
Sludge Notice of Availability.
Washington, D.C.
110. U.S. EPA. 1992. Sewage Sludge
Incinerator Total Hydrocarbon Analyzer
Evaluation. Office of Research and
Development, Wastewater Research
Division, Cincinnati, OH. EPA Contract
No. 60-CO-0027.
111. U.S. Geological Survey. 1981. Facing
Geologic and Hydrologic Hazards.
Geologic Survey Professional Paper
1240-B. Washington, D.C.
112. Van Genuchten, M. 1985. Convective-
Dispersive Transport of Solutes Involved
in Sequential First-order Decay
Reactions. J. Computers Geosci. 11:129.
113. Vlamis, J., D.E. Williams, J.E. Corey, A.L.
Page and T.J. Ganje. 1985. Zinc and
Cadmium Uptake by Barley in Field
Plots Fertilized Seven Years with Urban
and Suburban Sludge. Soil Sci. 139:81-
87. (As cited in: Page, A.L., T.H. Logan,
and J.A. Ryan, 1987.)
114. Water Pollution Control Federation.
1988 Incineration, Manual of Practice
No. OM-11. Alexandria, VA.
115. Water Resources Council. 1977.
Guidelines for Determining Flood Flow
Frequency. Bulletin Number 17A.
116. Webber, L.R., and E.G. Beauchamp.
1979. Cadmium Concentrations and
Distribution in Corn (Zea mays L.)
Grown on a Calcareous Soil for Three
Years After Three Annual Sludge
Applications. J. Environ. Sci. Health
B14(5):454-474.
117. Yeh, G.T. 1981. AT123D: Analytical
Transient One-, Two-, and Three-
Dimensional Simulation of Waste
Transport in the Aquifer System. Oak
Ridge National Laboratory,
Environmental Sciences Division, Oak
Ridge, TN. ORNL-5602.
Part XV: Description of the
Amendments to 40 CFR Parts 257 and
403
Amendment to 40 CFR Part 257
The existing requirements in 40 CFR
part 257 are applicable to all solid waste
disposal facilities and practices
regulated under sections 4004 and 4010
of the Resource Conservation and
Recovery Act. With certain exceptions,
the requirements in 40 CFR part 257
apply to all types of facilities (e.g.,
landfills, surface disposal sites, land
application units, and waste piles) used
for the disposal of solid waste and all
types of non-hazardous solid wastes
(i.e., municipal, industrial, commercial,
agricultural, mining, and oil and gas
wastes). Part 257 also applies to the
disposal of sewage sludge.
Included with the 1989 part 503
proposal was a proposed amendment to
part 257. The purpose of the
amendment was to delete the
requirements in part 257 that pertain to
sewage sludge. This included deleting
section 405(d) from the part 257
authority, deleting references to sewage
sludge in 257.1, revising the definitions
for "sludge" and "solid waste" in 257.2,
deleting the reference to sections 405(d)
and 405(e) from 257.3-4, and deleting
paragraphs (b) and (c) from 257.3-6.
These proposed changes are discussed
below with respect to the final
amendment to part 257 in today's
rulemaking. No comments were
received from the public on the
proposed part 257 amendment during
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9381
the comment period for the 1989
proposal.
The final part 503 regulation contains
requirements for sewage sludge applied
to the land, placed on a surface disposal
site, or fired in a sewage sludge
incinerator. There is one case, however,
that the part 503 requirements do not
apply to sewage sludge used or disposed
through those practices. Part 503 does
not apply to the use or disposal of
sewage sludge generated at an industrial
facility during the treatment of
industrial wastewater combined with
domestic sewage generated at the
industrial facility. That sewage sludge
has to meet the part 257 requirements if
it is disposed on the land. Because the
part 257 requirements continue to apply
to certain sewage sludges, today's
amendment does not delete section
405(d) from the part 257 authority.
Section 257.1(b)(l) was proposed to
be changed in the 1989 proposal to
indicate the part 257 criteria do not
apply to the use or disposal of sewage
sludge under section 405(d) of the Clean
Water Act. Because certain sewage
sludges are subject to the part 257
requirements, today's rulemaking
amends 257.1(b)(l) to indicate that part
257 contains guidelines for the disposal
of sewage sludge not used or disposed
through a practice regulated in 40 CFR
part 503. This means that part 257
applies if sewage sludge is disposed on
the land and if the sewage sludge is not
used or disposed in accordance with
part 503.
The 1989 proposal also proposed to
amend 257.1(c)(3) and 257.1(c)(4) by
deleting the last sentence in each
subsection. Today's part 257
amendment deletes the final sentence in
257.1(c)(3), but does not delete the final
sentence in 257.1(c)(4).
The last sentence in the current
257.1(c)(3) indicates that the part 257
criteria apply to disposal of sludges
generated by treatment of domestic
sewage. Because the applicability of part
257 to disposal of sewage sludge is
addressed in the amended 503.1(b)(l)
and in a new 503.1(c)(ll), the last
sentence no longer applies. For this
reason, it was deleted from 257.1(c)(3).
The last sentence in 257.1(c)(4)
concerning disposal of septic tank
pumpings is not being deleted in today's
amendment because part 257 still
applies to the disposal of pumpings
from septic tanks that receive
commercial or industrial wastewaters.
Use or disposal of pumpings from septic
tanks that receive only domestic sewage
(i.e., domestic septage) is addressed in
part 503.
The second revision to 257.1(c) in
today's amendment adds a new
provision at 257,l(c)(ll). This provision
indicates that the part 257 criteria do
not apply to the use or disposal of
sewage sludge, including domestic
septage, on the land when the sewage
sludge is used or disposed in
accordance with 40 CFR part 503. Note
that domestic septage does not include
pumpings from septic tanks that receive
commercial or industry wastewater. As
mentioned above, if those pumpings are
disposed on the land, the part 257
criteria apply. The Agency decided to
include this provision in 257.1(c) to
make it clear that sewage sludge used or
disposed in accordance with part 503 is
not subject to the part 257 requirements.
Another revision to part 257 in
today's rulemaking amends the
definition section (i.e., 257.2). In the
1989 proposal, 257.2 was proposed to be
changed by amending the terms
"sludge" and "solid waste" to indicate
that sewage sludge is not a sludge or a
solid waste. The Agency decided not to
amend those definitions in today's
amendment because certain sewage
sludges are still subject to the part 257
requirements. Instead, the definition of
"domestic septage" and "sewage
sludge" are being added to 257.2. These
terms are used in the revisions to 257.1.
The final revision in today's part 257
amendment concerns 257.3-4. This
subsection is being changed by adding
the phrase "with respect to sewage
sludge that is not used or disposed
through a practice regulated in 40 CFR
part 503" after "* * * a violation of
section 405(e) * * * ". Section 405(e)
indicates that the determination of the
manner of disposal or use of sewage
sludge is a local determination.
However, if the selected use or disposal
practice is regulated under section
405(d) of the CWA, the requirements in
405(d) have to be met. Because part 257
is promulgated under the authority of
405 (d) for sewage sludges that are not
regulated under part 503, section 257.3-
4(b)(l) is being amended to make it clear
that a party charged with a violation of
section 405(e) only with respect to
sewage sludge not regulated under 40
CFR part 503 may demonstrate that
compliance be determined at an
alternative boundary in lieu of the solid
waste boundary. This amendment does
not apply to a party charged with open
dumping.
The proposed part 257 amendment
also indicated that the Agency was
considering deleting paragraphs (b) and
(c) in 257.3-6. Because part 257
continues to apply to certain sewage
sludge disposed on the land, EPA
decided not to delete those paragraphs.
Paragraphs (b) and (c) still apply if
sewage sludge is disposed on the land
and if that sewage sludge is not used or
disposed in accordance with part 503.
Amendment to 40 CFR Part 403
Today's amendment to 40 CFR part
403 contains an appendix with two lists
of pollutants eligible for a removal
credit with respect to the use or disposal
of sewage sludge. The first list, G-I,
contains the pollutants controlled for
the various use or disposal practices
regulated by the part 503 regulation. If
a POTW complies with the part 503
pollutant limit for a part 503 use or
disposal practice and complies with the
other requirements in part 503 for that
practice, the pollutant is eligible for a
removal credit so long as other EPA
procedural and substantive
requirements found at 40 CFR 403.7 are
met.
For an inorganic pollutant listed in G-
I to be eligible for a removal credit when
present in sewage sludge that is fired in
a sewage sludge incinerator, the
concentration of the pollutant in the
sewage sludge cannot exceed the
concentration calculated using the
applicable equation in part 503. In
addition, part 503 requires that the
National Emission Standards for
Beryllium and Mercury in subparts C
and D of 40 CFR part 61, respectively,
and the Standards of Performance for
Sewage Treatment Plants in subpart O
of 40 CFR part 60 not be violated if
sewage sludge is fired in a sewage
sludge incinerator. These requirements
must be met before a removal credit can
be granted for the inorganic pollutants.
Part 503 also limits total hydrocarbon
(THC) in the exit gas from sewage
sludge incinerator stacks. Although the
THC limit is a technology-based
operational standard, in the judgment of
the Administrator of EPA that limit
protects public health and the
environment from the reasonably
anticipated adverse affects of certain
organic pollutants in the incinerator
stack exit gas. The 503 proposal listed
all of the organic pollutants for which
there were Q* values at that time. The
final part 503 regulation also includes
all organic pollutants for which there
are Q* values, including those for which
the values were developed after the
proposal. These pollutants are eligible
for a removal credit with respect to the
use or disposal of sewage sludge if the
THC limit is met; if the Standards of
Performance for Sewage Treatment
Plants in subpart O of 40 CFR part 60
are not violated; and if the other
removal credit requirements are met.
The second list, G-H in the appendix,
lists certain pollutants by use or
disposal practice and a concentration
for each pollutant. The Agency
-------
9382 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
determined that the pollutants on the
second list do not pose an unreasonable
risk to public health and the
cnvironmont if the concentrations for
those pollutants in the sewage sludge
are below the concentrations for the
pollutants in G-II list.
Pollutants were placed on the list hi
G-n for one of two reasons. First,
available data, which were based in
large part on the results of the 40 City
Study (Fate of Priority Pollutants in
Publicly Owned Treatment Works. Vol.
I, Washington, DC, U.S. EPA, 1984), at
the time the original list of pollutants of
concern for the part 503 regulation was
developed indicated that the
concentrations of the pollutants in
sewage sludge do not exceed the
concentrations for those pollutants on
the G-n list. EPA determined that, at
those concentrations, the pollutants do
not pose a throat to public health and
the environment at the highest levels
detected, and that it was not necessary
to expend additional resources to
determine what the highest possible
"safe level" would be. EPA decided that
those pollutants are eligible for a
removal credit with respect to the use or
disposal of sewage sludge if the
concentration of a pollutant in the
sewage sludge does not exceed the
concentration for the pollutant in G—II
and if the treatment works complies
with the applicable requirements in 40
CFR 403.7.
The second reason a pollutant was
placed on the list in G—II is that, after
determining a risk level for the
pollutant, EPA decided not to regulate
it In the final part 503 regulation. The
concentration for those pollutants in G—
II is the concentration developed during
the risk assessment for the final part 503
regulation. A removal credit is available
for those pollutants with respect to the
use or disposal of sewage sludge if the
concentration of the pollutant in the
POTW's sewage sludge is less than or
equal to the concentration for the
pollutant in G—II and if the treatment
works complies with the applicable
requirements in 40 CFR 403.7. These
pollutants are designated with an
asterisk on the G-II list.
Proof that the pollutant
concentrations in a POTW's sewage
sludge do not exceed the pollutant
concentrations on the G-II list must be
provided in the Sludge Management
Certification portion of a POTW's
removal credit application (see 40 CFR
403.7(o)(4)(v)). No further monitoring of
these pollutants is required unless
required by a sewage sludge permit. If
subsequent monitoring reveals that the
concentration of the pollutant in the
POTW's sewage sludge exceeds the
levels in the G-II list or any more
stringent limit in the POTW's sewage
sludge permit, the POTW is no longer
eligible for removal credit authority for
that pollutant. See 40 CFR 403.7(f)(4).
If the concentration listed in G—II is
below the limit of detection for the
pollutant (i.e., for N-
Nitrosodimethylamine), a POTW may be
granted removal credit authority for that
pollutant if the POTW shows that the
actual concentration in the sewage
sludge is below the detection limit,
unless a sewage sludge permit imposes
an actual limit below the detection
limit.
Today's amendment also indicates
that removal credit authority can be
granted to POTWs whose sewage sludge
is disposed of in a municipal solid
waste landfill (MSWLF) that meets the
criteria in 40 CFR part 258. Any
pollutant in sewage sludge for which a
categorical pretreatment standard has
been developed is eligible for a removal
credit because disposal of sewage sludge
in a MSWLF that meets the criteria in
40 CFR part 258 constitutes compliance
with section 405 of the Clean Water Act,
as amended. EPA published the final
part 258 regulations on October 11,1991
(56 FR 50977).
To receive removal credit authority
for a pollutant, a POTW also must
comply with the limits in a sewage
sludge permit. A permit writer might
apply such limits if site-specific
circumstances vary from the
assumptions underlying the pollutant
limits in today's rule. The POTW also
must comply with any applicable
provisions of the Clean Air Act and any
more stringent State or local regulations
to receive removal credit authority.
The remainder of the discussion on
today's amendment to part 403 reviews
the options considered during the
development of the appendix G lists.
Implementation of today's amendment
also is discussed further below.
When the proposal for part 503
regulation was published in February
1989, the Agency proposed that removal
credits be available with respect to the
use or disposal of sewage sludge for two
groups of pollutants. The first group
included pollutants regulated in part
503; removal credits would be available
for POTWs that complied with the part
503 requirements for the applicable use
or disposal practice. The second group
included pollutants not controlled in
part 503 because at the highest
concentrations detected in sewage
sludge, these pollutants did not present
an unreasonable risk to public health or
the environment.
In a Notice of Availability of
Information and Data from the National
Sewage Sludge Survey and Request for
Comments published in the Federal
Register in November 1990, the Agency
addressed whether removal credits
should be available for pollutants not
addressed in the initial part 503
regulation (known as "round one"
regulation). The Agency proposed and
invited comment in the Notice on four
options concerning the eligibility of a
pollutant for a removal credit with
respect to the use or disposal of sewage
sludge for a second round (i.e., round
two) of pollutants and for pollutants not
on either the "round one" or "round
two" lists. The four options were:
Option 1—A categorical pretreatment
standard pollutant is eligible for a
removal credit only if EPA has either
established a specific numerical limit
for that pollutant in part 503 or has
evaluated the pollutant and concluded
that it does not threaten public health
and the environment in sewage sludge
that is used or disposed.
Option 2—A categorical pretreatment
standard pollutant not controlled in the
part 503 regulation for either "round
one" or "round two" becomes eligible
for a removal credit with respect to the
use or disposal of sewage sludge when
the part 503 "round two" regulation is
promulgated.
Option 3—A categorical pretreatment
standard pollutant not controlled in the
part 503 regulation for "round one"
becomes eligible for a removal credit
with respect to the use or disposal of
sewage sludge if not identified by EPA
in the Federal Register as a pollutant
that may be regulated in "round two."
Option 4—A categorical pretreatment
standard pollutant not controlled in the
part 503 regulation for "round one"
becomes eligible for a removal credit
with respect to the use or disposal of
sewage sludge when the "round one"
regulation is promulgated.
After consideration of all of the
options and the comments addressing
those options, EPA selected Option 1,
which is included in today's
amendment to part 403. Removal credit
eligibility is limited to those pollutants
regulated specifically in part 503 and to
pollutants that the Agency determines
do not threaten public health and the
environment at specified
concentrations. Many commenters
supported Option 1 because that option
provides such a clear statement as to
which pollutants are eligible for a
removal credit.
As mentioned previously, section
307(b) authorizes removal credits only if
the resulting industrial discharges do
"not prevent sludge use or disposal by
such [POTW] in accordance with
section 405 * * * ". Section 307(b), 33
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9383
U.S.C. 1317(b). The Third Circuit in
NRDC v. EPA interpreted this language
to mean that removal credits only can be
granted if the comprehensive standards
under section 405(d) of the CWA, as
amended, are in place. Congress
affirmed the Third Circuit's holding by
adopting section 406 (e) of the Water
Quality Act. The legislative history for
section 406(e) indicates that Congress
wanted standards to be developed and
met prior to removal credits being
authorized. As Senator Stafford, one of
the sponsors of the Water Quality Act of
1987, pointed out (132 Cong. Rec.
S16427, daily ed. October 16,1986):
* * * Congress intended the existence of
sludge regulations, and compliance with
those regulations, to be a precondition to the
granting of removal credits.
Only then can it be determined if the
granting of a removal credit for a
specific pollutant results in
contamination of the POTW's sewage
sludge.
Although section 405 does not require
a limit to be developed for pollutants
that do not pose a risk, section 307(b)
requires compliance with a section 405
standard for a POTW to be granted
removal credit authority. The Agency
has resolved the potential conflict
between sections 307(b) and 405 by
allowing a removal credit for pollutants
not controlled in the part 503 regulation
provided EPA determines that
regulation is unnecessary to accomplish
the objective of section 405 to protect
public health and the environment from
the reasonably anticipated adverse
effects of the pollutant. Such a
determination has been made with
respect to the pollutants listed by use or
disposal practice on the G-II list in
today's amendment to part 403.
Note: Table 22 of the proposed rule
erroneously listed cyanide among the
pollutants for which removal credits would
be available for sludge that is land applied
or distributed and marketed; EPA has not
evaluated the risk of cyanide in these
practices and removal credits are not
available for them. To correct this error,
Table G-II in the final rule does not indicate
that removal credits for cyanide are available
where sewage sludge is land applied. The
final rule also clarifies that "total cyanide",
not "cyanide", is the parameter for which
removal credits may be available for surface
disposal.
EPA did not select Options 2 through
4, which would have made removal
credits available for additional
pollutants. Those options were
premised on the assumption that
"round one" and "round two"
regulations address substantially all the
universe of pollutants in sewage sludge
that may pose a threat to public health
and the environment. Whether that in
fact will be the case is not known at this
time. EPA will consider addressing in
"round two" the remaining priority
pollutants controlled by categorical
pretreatment standards. If those
pollutants are regulated in part 503,
Options 2, 3, and 4 become obsolete.
EPA cannot make removal credits
available for pollutants other than those
listed in appendix G at this time
because the Agency has not controlled
other pollutants in part 503. EPA has
not analyzed all of the data to determine
whether other pollutants present a risk
to public health and the environment in
sewage sludge that is used or disposed.
Several comments were received on
the four removal credit options in the
1990 Notice. The major comments are
discussed below and a response to those
comments is presented.
Some commenters recommended that
removal credits be abolished altogether.
Various reasons were given for these
recommendations including that
removal credits are inconsistent with
pollution prevention, erode public
confidence in sewage sludge quality,
and are unnecessary because industry is
already required to be in compliance
with categorical pretreatment standards.
Others opposed removal credits for any
use or disposal practice except for
beneficial use practices. Others opposed
removal credits if the removal credits
result in any deterioration of sewage
sludge quality.
The above commenters misconstrued
the scope of the removal credit
amendment in today's rule. Moreover,
regardless of the validity of the
comments, section 307{b) of the Clean
Water Act, as amended, provides that
the owner or operator of a POTW may
revise pretreatment standards, given
compliance with the statute.
One environmental group commented
that EPA could not make removal
credits available for any pollutant until
a limit is established for the pollutant.
EPA believes it is consistent with the
intent of CWA sections 307(b) and
405 (d) to make removal credits available
for pollutants present in sewage sludge
at levels that EPA has determined do
not affect public health and the
environment adversely. The Agency
decided not to regulate pollutants for
which the concentration that protects
public health and the environment is
above any concentration that has been
detected in sewage sludge. Such
regulation would result in costly
monitoring for no foreseeable benefit.
This same commenter stated that EPA
could not make removal credits
available unless EPA subjected the
pollutant to the same analysis to which
regulated pollutants were subjected. The
Agency does not believe it is necessary
to perform an equally intensive risk
assessment for every pollutant for the
pollutant to be eligible for a removal
credit. The resources devoted to
assessing a pollutant should be
increased when there is an indication
that a pollutant presents an
unreasonable risk to public health and
the environment. Relatively little
information collection and analysis may
be necessary if there is little or no
evidence that a pollutant presents a risk
when present in sewage sludge.
The CWA, as amended, does not
specify the types or amount of studies
that must be performed to support a
decision to regulate a pollutant under
section 405. It also does not require that
limits be developed for pollutants that
do not present a risk to public health or
the environment or are not likely ever
to be present in sewage sludge in
concentrations that could present such
a risk. The Agency does believe,
however, that for the purposes of
authorizing a removal credit under
section 307(b), EPA must distinguish
those pollutants that do not present a
risk from those for which adequate data
do not exist to allow such a
determination. Although it is not
necessary to develop section 405
standards for every pollutant for which
a removal credit may be authorized, it
is necessary for EPA to consider
whether section 405 requires a pollutant
to be regulated. The Agency believes
that it has met this requirement with
respect to the pollutants listed on the G-
II list in today's amendment to part 403.
Commenters argued that EPA could
not make any removal credits available
based on EPA's analysis of data from the
40 City Study. Removal credits are
available for the pollutants listed in G-
II because, at the highest values shown,
EPA determined they do not present an
unreasonable risk for one or more use or
disposal practices. Many of the
pollutant concentrations in G-II are the
highest concentrations detected in the
40 City Study. At the time of the
February 1989 proposal, EPA decided
not to subject these pollutants to the
full-scale risk assessment to which
pollutants proposed for regulation were
subjected. Because EPA had already
determined that the pollutants do not
pose a threat to public health and the
environment at the highest levels
detected, it was not necessary to expend
additional resources to determine what
the highest possible "safe level" would
be. EPA decided it should instead
concentrate its resources on studying
those pollutants that EPA's preliminary
-------
9384 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
assessments indicated might pose a risk
at existing levels.
EPA recognizes that the data from the
National Sewage Sludge Survey (NSSS)
is more reflective of current sewage
sludge quality than the data from the 40
City Study. It may in fact be the case
that EPA's analysis of the NSSS data
during "round two" will indicate that
certain pollutants on the G—II list are
present in concentrations that merit
regulation. The fact that the 40 City
Study may have given an inaccurate
indication of the maximum
concentration of a pollutant present in
any sewage sludge does not, however,
change EPA's conclusion that the
pollutants are "safe" at the 40 City
Study levels. Examination of the NSSS
data on the concentrations of these
pollutants may lead to a conclusion that
the "safe level" may be higher than the
40 City Study levels or may lead to a
conclusion that these pollutants need to
bo regulated. This will not, in the
absence of other information, change
EPA's determination that the lower
levels detected in the 40 City Study are
"safe".
Also included on the G-II list are
concentrations for organic pollutants
based on the results of the risk
assessment for the part 503 regulation.
These pollutants were deleted from the
part 503 regulation for various reasons
after the part 503 risk assessment was
completed. The concentrations for these
pollutants in G—II are the concentrations
based on the results of the part 503 risk
assessment. If the concentration for the
pollutant is below the concentration on
the G-II list, public health and the
environment are protected from the
reasonably anticipated adverse effects of
the pollutants in sewage sludge that is
used or disposed. These pollutants are
marked with an asterisk on the G-II list.
Some commenters argued that
removal credits must be made available
for any pollutant not regulated by the
final part 503 regulation. The Agency
believes, however, that the CWA, as
amended, only allows removal credits
for the pollutants in appendix G. When
read together, sections 307(b) and 405
permit removal credits only when it can
bo determined that the increased
concentrations or amounts allowed by
the removal credit does not affect
sewage sludge use or disposal adversely.
It may in fact be the case that the use
or disposal of sewage sludge is not
affected adversely by some pollutants
for which standards are not being
promulgated today. For pollutants other
than those in appendix G, it cannot be
determined, however, whether
pollutants were not selected for
regulation because they were believed to
be "safe" or because there are not
adequate data to determine a "safe
level". As previously noted, for
example, dioxin is not a pollutant that
is regulated in this rulemaking today.
Dioxins, which may be present in
sewage sludge, are not regulated not
because they are believed safe but
because at the time EPA initially
screened pollutants for regulation it
lacked data to evaluate dioxins for
regulation.
Some commenters assumed
incorrectly that the pollutants on Table
IH-3 in the preamble for the proposed
part 503 regulation were the only
pollutants for which EPA lacked
adequate data to establish a "safe level".
Table in-3 listed the pollutants that
were recommended for further study but
for which a positive determination was
made subsequently that EPA lacked
sufficient data to establish a safe level.
There are other pollutants that may have
not been recommended for study
because EPA lacked data regarding the
risk they presented.
In the view of some commenters, this
approach excludes unfairly from
removal credit eligibility pollutants that
may represent little or no threat to
public health and the environment
simply because EPA has not evaluated
them formally for environmental threat.
EPA recognizes that the part 503
pollutants regulated in "Round One"
generally represent those pollutants in
sewage sludge with the greatest
potential for threatening public health
and the environment. However, it must
be recognized that the decision to
regulate some pollutants and not others '
was in part based on the availability of
information on the pollutants. EPA
solicited comments and data to support
whether additional or fewer pollutants
should be regulated but received little
response. The decision not to regulate
does not necessarily mean that the
unregulated pollutants may not threaten
public health and the environment.
EPA soh'cited comment on whether,
in those cases where the Agency
regulates 4AAP (a test measurement) as
an indicator for various phenolic
compounds, removal credits should be
allowed for all of the compounds
represented by 4AAP although only the
parent compound phenol and certain
other phenolic compounds were subject
to environmental assessments in this
rulemaking. Commenters did not
provide EPA with data that 4AAP
reflects the different phenolic
compounds in wastewater. Therefore,
removal credits only are available for
the specific phenolic compounds listed
on the G—II in the appendix to today's
part 403 amendment.
EPA solicited comment whether a
specific categorical pretreatment
standard pollutant not regulated in part
503 should be eligible for a removal
credit and whether the concentrations
on the G-n list were appropriate. One
commenter noted that the
demonstration procedure is so costly
and time consuming that it is unlikely
that additional chemicals would be
added before the deadline for
categorical standards. EPA notes that
the degree of information and expense
required should increase with evidence
of risk, but that in any case, EPA's
decisions must be based on such
information. The only detailed data
submitted to EPA addressed the
adequacy of the cap for chromium. After
further analysis of all available data
regarding chromium in sewage sludge,
EPA decided to regulate chromium in
part 503. For this reason, chromium is
listed on the G-I lists rather than on the
G-II list.
The concentrations listed on the G-II
list are a cap for the availability of
removal credits for the pollutants by use
or disposal practice. EPA will study the
NSSS data during "Round Two" for the
part 503 regulation to determine
whether these levels should be raised or
if the pollutants should be regulated at
some other level. If an industrial
discharger believes that removal credit
authority should be made available for
a pollutant that is present in a POTW's
sewage sludge at a higher level than the
level on the G—II list, the industry
should provide to EPA information on
those concentrations and any
information of the risk presented by
such concentrations.
One commenter recommended that
removal credits be available for
pollutants that cannot be detected in a
POTW's sewage sludge. The "safe level"
might be below the detection limit for
some or all test procedures. The Agency
believes, therefore, that it must
determine the "safe level" of a pollutant
before removal credit authority can be
granted for that pollutant.
This commenter listed several
pollutants found rarely in sewage sludge
sampled in the National Sewage Sludge
Survey. EPA has not yet analyzed the
data on these pollutants to determine if
it is adequate to support a decision not
to regulate the pollutants. Before a
removal credit can be authorized, EPA
has to at least establish that the highest
detected levels do not present a risk.
The Agency hopes to perform that
analysis for the "Round Two" part 503
regulation. Before that time, removal
credits only are available for the
pollutants listed in G—I or G—II.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9385
Another commenter recommended
that EPA consider allowing a POTW to
grant a removal credit for any pollutant
that cannot be detected in the POTW's
effluent. This is not within the scope of
this rulemaking. The Agency notes,
however, that the burden of proof is on
the POTW that seeks removal credit
authority to establish that it is
accomplishing consistent removal of the
pollutant. The methods by which
consistent removal can be established is
not the subject of today's rule (see 40
CFR 403.7(b)(l)).
Prior to 1986, one POTW was
authorized to grant removal credits for
ammonia and oil and grease. This
POTW commented that EPA should
clarify that removal credits are available
for conventional and non-conventional
pollutants. As discussed above, EPA has
determined that before it can make
removal credits available for a particular
pollutant not regulated under Part 503,
it needs to determine that regulation of
that pollutant is not necessary to protect
public health and the environment from
the reasonably anticipated adverse
effects of that pollutant. Ammonia and
oil and grease are not regulated under
today's final part 503 standards and
EPA has not made the necessary
determination that regulation is not
necessary. Removal credits for ammonia
and oil and grease, therefore, are not
available at this time. However, as
previously explained, EPA will evaluate
a number of pollutants for regulation in
"Round Two." Its conclusions about
which pollutants may be proposed for
regulation in "Round Two" must be
made by late May, 1993. EPA is
considering at this time not only which
pollutants may be proposed for
regulation but also the process for
determining how to evaluate
unregulated pollutants for removal
credit purposes.
With respect to implementation of a
.removal credit, publication of the part
503 regulation does not entitle a POTW
automatically to removal credit
authority for a pollutant. The POTW
must manage all of the sewage sludge in
compliance with the use or disposal
practice covered by part 503; removal
credits may not be authorized before the
part 503 requirements are met. To be
eligible for removal credit authority, the
POTW must comply, with the
substantive use or disposal practice
requirements and any requirement
related to sewage sludge use or disposal
for each pollutant for which it seeks
removal credit authority. POTWs that
dispose of sewage sludge in a municipal
solid waste landfill that complies with
the criteria in 40 CFR part 258 also may
obtain removal credit authority for any
categorical pretreatment standard
pollutant in the sewage sludge placed in
the MSWLF.
To obtain removal credit authority, a
POTW must apply to EPA or to a State
that has been approved to administer
the Pretreatment Program. The
application for removal credit authority
must demonstrate that the POTW is in
compliance with the removal credit
regulations in 40 CFR 403.7. Only
POTWs may submit the application;
industrial facilities cannot apply,
although they may assist the POTW in
preparing an application. A POTW must
have an approved pretreatment program
at the time removal credit authority is
granted and may extend all or part of
any authorized removal credit to an
industrial user.
In addition to establishing compliance
with the conditions applicable to the
use or disposal of sewage sludge, the
POTW's removal credit application
must provide data on the percentage of
each pollutant removed from the
wastewater consistently by the POTW.
Removal credits cannot be granted if
they cause the POTW to violate its
NPDES permit. If the POTW is subject
to combined sewer overflows, the
application must establish that the
POTW is taking certain actions to
eliminate the combined sewer
overflows. Each of these requirements is
described more fully in 40 CFR 403.7.
Complete applications are reviewed
by EPA or a State that has been
approved to administer the Pretreatment
Program. When the application is
submitted to an Approved State, EPA
Regions have the right to review and
object to a State's approval of a
submission, unless the right has been
waived in the Region's Memorandum of
Agreement with the State. After a period
of review and public comment, removal
credit authority may be granted to any
POTW that complies with the
procedural and substantive
requirements of the removal credits
regulations. Following approval,
POTWs must continue to sample
monthly to demonstrate continued
removal of the pollutant. The POTW's
demonstrated consistent pollutant
removal becomes an enforceable part of
its NPDES permit. Authority to grant a
removal credit can be modified or
withdrawn if a POTW fails to continue
to achieve consistent removal, fails to
comply with part 503 requirements, or
no longer satisfies any other
requirement of 40 CFR 403.7.
List of Subjects
40 CFR Part 257
Facilities and practices, Sewage
sludge, Sludge, and Solid waste.
40 CFR Part 403
Incineration, Land application,
Pollutants, Removal credits, Sewage
sludge, and Surface disposal.
40 CFR Part 503
Frequency of monitoring,
Incineration, Incorporation by reference,
Land application, Management
practices, Pathogens, Pollutants,
Reporting and recordkeeping
requirements, Sewage sludge, Surface
disposal, and Vector attraction.
Dated: November 25,1992.
F. Henry Hubicht II,
Acting Administrator.
For reasons set out in the preamble,
title 40 of the Code of Federal
Regulations is amended as set forth
below:
PART 257—CRITERIA FOR
CLASSIFICATION OF SOLID WASTE
DISPOSAL FACILITIES AND
PRACTICES
1. The authority citation for 40 CFR
part 257 continues to read as follows:
Authority: 42 U.S.C. 6907(a)(3), 6944(a)
and 6949(c), 33 U.S.C. 1345 (d) and (e).
2. Section 257.1 is amended by
revising paragraphs (b) and (c)(3) to read
as follows and by adding a new
paragraph (c)(ll) to read as follows:
§ 257.1 Scope and purpose.
*****
(b) These criteria also provide
guidelines for the disposal of sewage
sludge on the land when the sewage
sludge is not used or disposed through
a practice regulated in 40 CFR part 503.
(c) * * *
(3) The criteria do not apply to the
land application of domestic sewage or
treated domestic sewage.
*****
(11) The criteria do not apply to the
use or disposal sewage sludge on the
land when the sewage sludge is used or
disposed in accordance with 40 CFR
part 503.
3. Section 257.2 is amended by
adding definitions in alphabetical order
for "domestic septage" and "sewage
sludge" to read as follows:
§257.2 Definitions.
*****
Domestic septage is either liquid or
solid material removed from a septic
tank, cesspool, portable toilet, Type HI
marine sanitation device, or similar
-------
9386 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
treatment works that receives only
domestic sewage. Domestic septage does
not include liquid or solid material
removed from a septic tank, cesspool, or
similar treatment works that receives
either commercial wastewater or
industrial wastewater and does not
include grease removed from a grease
trap at a restaurant.
*****
Sewage sludge means solid, semi-
solid, or liquid residue generated during
the treatment of domestic sewage in a
treatment works. Sewage sludge
includes, but is not limited to, domestic
soptngo; scum or solids removed in
primary, secondary, or advanced
wastowoter treatment processes; and a
material derived from sewage sludge.
Sewage sludge does not include ash
generated during the firing of sewage
sludge in a sewage sludge incinerator or
grit and screenings generated during
preliminary treatment of domestic
sewage in a treatment works.
*****
4. Section 257.3-4 is amended by
revising paragraph (b)(l) introductory
text to read as follows:
§257.3-4 Ground water.
*****
(b)(l) For purposes of section
1008(a)(3) of the Act or section 405(d)
of the CVVA, a party charged with open
dumping or a violation of section 405(e)
with respect to sewage sludge that is not
used or disposed through a practice
regulated in 40 CFR part 503 may
demonstrate that compliance should be
determined at an alternative boundary
in lieu of the solid waste boundary. The
court shall establish an alternative
boundary only if it finds that such a
change would not result in
contamination of ground water which
may bo needed or used for human
consumption. This finding shall be
based on analysis and consideration of
all of the following factors that are
relevant:
PART 403—GENERAL
PRETREATMENT REGULATIONS FOR
EXISTING AND NEW SOURCES OF
POLLUTION
1. The authority citation for 40 CFR
part 403 continues to read as follows:
Authority: Sec. 54(c)(2) of the Clean Water
Act of 1977, (Pub. L. 95-217) sections
204(b)(l)(C), 208(b)(2)(C)(iii), 301(b)(l)(A)(ii),
301(b)(2)(A)(ii), 301(b)(2)(C), 301(h)(5),
301(i)(2), 304(e), 304(g), 307, 308, 309,
402(b), 405 and 501(a) of the Federal Water
Pollution Control Act (Pub. L. 92-500) as
amended by the Clean Water Act of 1977 and
the Water Quality Act of 1987 (Pub. L. 100-
4).
2. Section 403.7 is amended by
adding a sentence to the end of
paragraph (a)(3)(iv) and by adding
paragraphs (a)(3)(iv) (A) through (C) to
read as follows:
§403.7 Removal credits.
(a)* * *
(3) * * *
(iv) * * * Removal credits may be
made available for the following
pollutants.
(A) For any pollutant listed in
appendix G section I of this part for the
use or disposal practice employed by
the POTW, when the requirements in 40
CFR part 503 for that practice are met.
(B) For any pollutant listed in
appendix G section II of this part for the
use or disposal practice employed by
the POTW when the concentration for a
pollutant listed in appendix G section II
of this part in the sewage sludge that is
used or disposed does not exceed the
concentration for the pollutant in
appendix G section II of this part.
(C) For any pollutant in sewage sludge
when the POTW disposes all of its
sewage sludge in a municipal solid
waste landfill unit that meets the
criteria in 40 CFR part 258.
*****
3. 40 CFR part 403 is amended by
adding appendix G to read as follows:
Appendix G to Part 403—Pollutants
Eligible for a Removal Credit
I. Regulated Pollutants in Part 503 Eligible for
a Removal Credit
Pollutants
Arsenic
Beryllium
Cadmium
Coooer
Lead
Mercury
Molybdenum .. .
Nickel
Selenium
Zinc
Total hydrocarbons .. ..
Use or disposal prac-
tice
LA
X
X
X
X
X
X
X
X
X
X
SD
X
X
X
»
1
X.
X.
X.
X.
X.
X.
X.
X(1).
Key: LA—land application, SD—surface disposal
site without a liner and leachate collection system,
I—firing of sewage sludge in a sewage sludge
incinerator.
(1) The following organic pollutants are
eligible for a removal credit if the
requirements for total hydrocarbons in
subpart E in 40 CFR part 503 are met when
sewage sludge is fired in a sewage sludge
incinerator: Acrylonitrile, Aldrin/Dieldrin
(total), Benzene, Benzidine, Benzo(a)pyrene,
Bis(2-chloroethyl)ether, Bis(2-
ethylhexyljphthalate,
Bromodichloromethane, Bromoethane,
Bromoform, Carbon tetrachloride, Chlordane,
Chloroform, Chloromethane, DDD.DDE.DDT,
Dibromochloromethane, Dibutyl phthalate,
1,2-dichloroethane, 1,1-dichloroethylene,
2,4-dichlorophenol 1,3-dichloropropene,
Diethyl phthalate, 2,4-dinitrophenol, 1,2-
diphenylhydrazine, Di-n-butyl phthalate,
Endosulfan, Endrin, Ethylbenzene,
Heptachlor, Heptachlor epoxide,
Hexachlorobutadiene, Alpha-
hexachlorocyclohexane,
Betahexachlorocyclohexane,
Hexachlorocyclopentadiene,
Hexachloroethane, Hydrogen cyanide,
Isophorone, Lindane, Methylene chloride,
Nitrobenzene, N-Nitrosodimethylamine,
N-Nitrosodi-n-propylamine,
Pentachlorophenol, Phenol, Polychlorinated
biphenyls, 2,3,7,8-tetrachlorodibenzo-p-
dioxin, 1,1,2,2,-tetrachloroethane,
Tetrachloroethylene, Toluene, Toxaphene,
Trichloroethylene, 1,2,4-Trichlorobenzene,
1,1,1-Trichloroethane, 1,1,2-Trichloroethane,
and 2,4,6-Trichlorophenol.
II. Additional Pollutants Eligible for a
Removal Credit (milligrams per kilogram—
dry weight basis)
Pollutant
Arsoflic
AkJtfcVDtokJrio (Total) . .
Bonzono
Bonzo{8}pyfGfiQ ....
Bis(2'0(hythoxy1)phlhlia!o .
CfloVnluro «... ............ . .
ChkxdaoG
Use or disposal practice
LA
2.7
316
15
86
(SD)
Unlined1
140
3100
3100
3100
3100
Lined2
3100
3400
3100
100
3100
3100
I
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9387
Pollutant
Chromium
Copper
ODD, DDE, DDT (Total)
2,4 Diohlorophenoxy-acetlc acid
Fluoride
Heptachlor
Hexachlorobenzene
Hexachlorobutadiene
Iron
Lead
Lindane
Malathion
Mercury
Molybdenum
Nickel
N-Nitrosodimethylamine
Pentachlorophenol
Phenol
Polychlorinated biphenyls
Selenium
Toxaphene
Trichloroethylene
Zinc
Use or disposal practice
LA
1.2
730
7.4
29
600
3 78
84
2.1
30
4.6
10
310
(SD)
Unlined1
346
2000
7
3100
328
0.63
3100
40
0.088
82
<50
4.8
326
9500
4500
Lined2
3100
3100
2000
7
3100
3 28
0.63
3100
40
3100
0.088
82
<50
4.8
326
310
4500
I
1400
4.8
4500
Key: LA—land application, SD—surface disposal, I—incineration.
1 Sewage sludge unit without a liner and leachate collection system.
2 Sewage sludge unit with a liner and leachate collection system.
3 Value expressed in grams per kilogram—dry weight basis.
Subchapter O in chapter I of title 40
of the Code of Federal Regulations is
amended by adding part 503, which
reads as follows:
SUBCHAPTER O—SEWAGE SLUDGE
PART 503—STANDARDS FOR THE
USE OR DISPOSAL OF SEWAGE
SLUDGE
Subpart A—General Provisions
Sec.
503.1
503.2
503.3
503.4
503.5
Purpose and applicability.
Compliance period.
Permits and direct enforceability
Relationship to other regulations.
Additional or more stringent
requirements.
503.6 Exclusions.
503.7 Requirement for a person who
prepares sewage sludge.
503.8 Sampling and analysis.
503.9 General definitions.
Subpart B—Land Application
503.10 Applicability.
503.11 Special definitions.
503.12 General requirements.
503.13 Pollutant limits.
503.14 Management practices.
503.15 Operational standards—pathogens
and vector attraction reduction.
503.16 Frequency of monitoring.
503.17 Recordkeeping.
503.18 Reporting.
Subpart C—Surface Disposal
503.20 Applicability.
503.21 Special definitions.
503.22 General requirements.
503.23 Pollutant limits (other than domestic
septage).
503.24 Management practices.
503.25 Operational standards—pathogens
and vector attraction reduction.
503.26 Frequency of monitoring.
503.27 Recordkeeping.
503.28 Reporting.
Subpart D—Pathogens and Vector
Attraction Reduction
503.30 Scope.
503.31 Special definitions.
503.32 Pathogens.
503.33 Vector attraction reduction.
Subpart E—Incineration
503.40 Applicability.
503.41 Special definitions.
503.42 General requirements.
503.43 Pollutant limits.
503.44 Operational" standard—total
hydrocarbons.
503.45 Management practices.
503.46 Frequency of monitoring.
503.47 Recordkeeping.
503.48 Reporting.
Appendix A to Part 503—Procedure to
Determine the Annual Whole Sludge
Application Rate for a Sewage Sludge
Appendix B to Part 503—Pathogen
Treatment Processes
Authority: Sections 405 (d) and (e) of the
Clean Water Act, as amended by Pub. L. 95-
217, Sec. 54(d), 91 Stat. 1591 (33 U.S.C. 1345
(d) and (e)); and Pub. L. 100-4, Title IV, Sec.
406 (a), (b), 101 Stat., 71, 72 (33 U.S.C. 1251
et seq.).
Subpart A—General Provisions
§ 503.1 Purpose and applicability.
(a) Purpose. (1) This part establishes
standards, which consist of general
requirements, pollutant limits,
management practices, and operational
standards, for the final use or disposal
of sewage sludge generated during the
treatment of domestic sewage in a
treatment works. Standards are included
in this part for sewage sludge applied to
the land, placed on a surface disposal
site, or fired in a sewage sludge
incinerator. Also included in this part
are pathogen and alternative vector
attraction reduction requirements for
sewage sludge applied to the land or
placed on a surface disposal site.
(2) In addition, the standards in this
part include the frequency of
monitoring and recordkeeping
requirements when sewage sludge is
applied to the land, placed on a surface
disposal site, or fired in a sewage sludge
incinerator. Also included in this part
are reporting requirements for Class I
sludge management facilities, publicly
owned treatment works (POTWs) with a
design flow rate equal to or greater than
one million gallons per day, and POTWs
that serve 10,000 people or more.
(b) Applicability. (1) This part applies
to any person who prepares sewage
sludge, applies sewage sludge to the
land, or fires sewage sludge in a sewage
sludge incinerator and to the owner/
operator of a surface disposal site.
(2) This part applies to sewage sludge
applied to the land, placed on a surface
disposal site, or fired in a sewage sludge
incinerator.
(3) This part applies to the exit gas
from a sewage sludge incinerator stack.
-------
9388 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(4) This part applies to land where
sewage sludge is applied, to a surface
disposal site, and to a sewage sludge
incinerator.
§503.2 Compliance period.
(a) Compliance with the standards in
this part shall he achieved as
oxpoditiously as practicable, hut in no
case later than February 19,1994. When
compliance with the standards requires
construction of new pollution control
facilities, compliance with the standards
shall be achieved as expeditiously as
practicable, but in no case later than
February 19,1995.
(b) The requirements for frequency of
monitoring, recordkeeping, and
reporting in this part for total
hydrocarbons in the exit gas from a
salvage sludge incinerator are effective
February 19,1994 or, if compliance
with the operational standard for total
hydrocarbons in this part requires the
construction of new pollution control
facilities, February 19,1995.
(c) All other requirements for
frequency of monitoring, recordkeeping,
and reporting in this part are effective
on July 20,1993.
§ 503.3 Permits and direct enforceability.
(a) Permits. The requirements in this
part may be implemented through a
permit:
(1) Issued to a "treatment works
treating domestic sewage", as defined in
40 CFR 122.2, in accordance with 40
CFR parts 122 and 124 by EPA or by a
State that has a State sludge
management program approved by EPA
In accordance with 40 GFR part 123 or
40 CFR part 501 or
(2) Issued under subtitle C of the
Solid Waste Disposal Act; part C of the
Safe Drinking Water Act; the Marine
Protection, Research, and Sanctuaries
Act of 1972; or the Clean Air Act.
"Treatment works treating domestic
sewage" shall submit a permit
application in accordance with either 40
CFR 122.21 or an approved State
program.
(b) Direct enforceability. No person
shall use or dispose of sewage sludge
through any practice for which
requirements are established in this part
except in accordance with such
requirements.
§ 503.4 Relationship to other regulations.
Disposal of sewage sludge in a
municipal solid waste landfill unit, as
defined in 40 CFR 258.2, that complies
with the requirements in 40 CFR part
258 constitutes compliance with section
405(d) of the CWA. Any person who
prepares sewage sludge that is disposed
in a municipal solid waste landfill unit
shall ensure that the sewage sludge
meets the requirements in 40 CFR part
258 concerning the quality of materials
disposed in a municipal solid waste
landfill unit.
§ 503.5 Additional or more stringent
requirements.
(a) On a case-by-case basis, the
permitting authority may impose
requirements for the use or disposal of
sewage sludge in addition to or more
stringent than the requirements in this
part when necessary to protect public
health and the environment from any
adverse effect of a pollutant in the
sewage sludge.
(b) Nothing in this part precludes a
State or political subdivision thereof or
interstate agency from imposing
requirements for the use or disposal of
sewage sludge more stringent than the
requirements in this part or from
imposing additional requirements for
the use or disposal of sewage sludge.
§503.6 Exclusions.
(a) Treatment processes. This part
does not establish requirements for
processes used to treat domestic sewage
or for processes used to treat sewage
sludge prior to final use or disposal,
except as provided in § 503.32 and
§503.33.
(b) Selection of a use or disposal
practice. This part does not require the
selection of a sewage sludge use or
disposal practice. The determination of
the manner in which sewage sludge is
used or disposed is a local
determination.
(c) Co-firing of sewage sludge. This
part does not establish requirements for
sewage sludge co-fired in an incinerator
with other wastes or for the incinerator
in which sewage sludge and other
wastes are co-fired. Other wastes do not
include auxiliary fuel, as defined in 40
CFR 503.41(b), fired in a sewage sludge
incinerator.
(d) Sludge generated at an industrial
facility. This part does not establish
requirements for the use or disposal of
sludge generated at an industrial facility
during the treatment of industrial
wastewater, including sewage sludge
generated during the treatment of
industrial wastewater combined with
domestic sewage.
(e) Hazardous sewage sludge. This
part does not establish requirements for
the use or disposal of sewage sludge
determined to be hazardous in
accordance with 40 CFR part 261.
(f) Sewage sludge with high PCB
concentration. This part does not
establish requirements for the use or
disposal of sewage sludge with a
concentration of polychlorinated
biphenyls (PCBs) equal to or greater
than 50 milligrams per kilogram of total
solids (dry weight basis).
(g) Incinerator ash. This part does not
establish requirements for the use or
disposal of ash generated during the
firing of sewage sludge in a sewage
sludge incinerator.
(h) Grit and screenings. This part does
not establish requirements for the use or
disposal of grit (e.g., sand, gravel,
cinders, or other materials with a high
specific gravity) or screenings (e.g.,
relatively large materials such as rags)
generated during preliminary treatment
of domestic sewage in a treatment
works.
(i) Drinking water treatment sludge.
This part does not establish
requirements for the use or disposal of
sludge generated during the treatment of
either surface water or ground water
used for drinking water.
(j) Commercial and industrial septage.
This part does not establish
requirements for the use or disposal of
commercial septage, industrial septage,
a mixture of domestic septage and
commercial septage, or a mixture of
domestic septage and industrial septage.
§ 503.7 Requirement for a person who
prepares sewage sludge.
Any person who prepares sewage
sludge shall ensure that the applicable
requirements in this part are met when
the sewage sludge is applied to the land,
placed on a surface disposal site, or
fired in a sewage sludge incinerator.
§ 503.8 Sampling and analysis.
(a) Sampling. Representative samples
of sewage sludge that is applied to the
land, placed on a surface disposal site,
or fired in a sewage sludge incinerator
shall be collected and analyzed.
(b) Methods. The materials listed
below are incorporated by reference in
this part. These incorporations by
reference were approved by the Director
of the Federal Register in accordance
with 5 U.S.C. 552(a) and 1 CFR part 51.
The materials are incorporated as they
exist on the date of approval, and notice
of any change in these materials will be
published in the Federal Register. They
are available for inspection at the Office
of the Federal Register, 7th Floor, suite
700, 800 North Capitol Street, NW.,
Washington, DC, and at the Office of
Water Docket, room L-102, U.S.
Environmental Protection Agency, 401
M Street, SW., Washington, DC. Copies
may be obtained from the standard
producer or publisher listed in the
regulation. Methods in the materials
listed below shall be used to analyze
samples of sewage sludge.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9389
(1) Enteric viruses. ASTM
Designation: D 4994-89, "Standard
Practice for Recovery of Viruses From
Wastewater Sludges", 1992 Annual
Book of ASTM Standards: Section 11—
Water and Environmental Technology,
ASTM, 1916 Race Street, Philadelphia,
PA 19103-1187.
(2) Fecal coliform. Part 9221E. or Part
9222 D., "Standard Methods for the
Examination of Water and Wastewater",
18th Edition, 1992, American Public
Health Association, 1015 15th Street,
NW., Washington, DC 20005.
(3) Helminth ova. Yanko, W.A.,
"Occurrence of Pathogens in
Distribution and Marketing Municipal
Sludges", EPA 600/1-87-014,1987.
National Technical Information Service,
5285 Port Royal Road, Springfield,
Virginia 22161 (PB 88-154273/AS).
(4) Inorganic pollutants. "Test
Methods for Evaluating Solid Waste,
Physical/Chemical Methods", EPA
Publication SW-846, Second Edition
(1982) with Updates I (April 1984) and
II (April 1985) and Third Edition
(November 1986) with Revision I
(December 1987). Second Edition and
Updates I and II are available from the
National Technical Information Service,
5285 Port Royal Road, Springfield,
Virginia 22161 (PB-87-120-291). Third
Edition and Revision I are available
from Superintendent of Documents,
Government Printing Office, 941 North
Capitol Street, NE., Washington, DC
20002 (Document Number 955-001-
00000-1).
(5) Salmonella sp. bacteria. Part 9260
D., "Standard Methods for the
Examination of Water and Wastewater",
18th Edition, 1992, American Public
Health Association, 1015 15th Street,
NW., Washington, DC 20005; or
Kenner, B.A. and H.P. Clark,
"Detection and enumeration of
Salmonella and Pseudomonas
aeruginosa", Journal of the Water
Pollution Control Federation, Vol. 46,
no. 9, September 1974, pp. 2163-2171.
Water Environment Federation, 601
Wythe Street, Alexandria, Virginia
22314.
(6) Specific oxygen uptake rate. Part
2710 B., "Standard Methods for the
Examination of Water and Wastewater",
18th Edition, 1992, American Public
Health Association, 1015 15th Street,
NW., Washington, DC 20005.
(7) Total, fixed, and volatile solids.
Part 2540 G., "Standard Methods for the
Examination of Water and Wastewater",
18th Edition, 1992, American Public
Health Association, 1015 15th Street,
NW., Washington, DC 20005.
§503.9 General definitions.
(a) Apply sewage sludge or sewage
sludge applied to the land means land
application of sewage sludge.
(b) Base flood is a flood that has a one
percent chance of occurring in any
given year (i.e., a flood with a
magnitude equalled once in 100 years).
(c) Class I sludge management facility
is any publicly owned treatment works
(POTW), as defined in 40 CFR 501.2,
required to have an approved
pretreatment program under 40 CFR
403.8(a) (including any POTW located
in a State that has elected to assume
local program responsibilities pursuant
to 40 CFR 403.10(e)) and any treatment
works treating domestic sewage, as
defined in 40 CFR 122.2, classified as a
Class I sludge management facility by
the EPA Regional Administrator, or, in
the case of approved State programs, the
Regional Administrator in conjunction
with the State Director, because of the
potential for its sewage sludge use or
disposal practice to affect public health
and the environment adversely.
(d) Cover crop is a small grain crop,
such as oats, wheat, or barley, not grown
for harvest.
(e) CWA means the Clean Water Act
(formerly referred to as either the
Federal Water Pollution Act or the
Federal Water Pollution Control Act
Amendments of 1972), Public Law 92-
500, as amended by Public Law 95—217,
Public Law 95-576, Public Law 96-483,
Public Law 97-117, and Public Law
100-4.
(f) Domestic septage is either liquid or
solid material removed from a septic
tank, cesspool, portable toilet, Type in
marine sanitation device, or similar
treatment works that receives only
domestic sewage. Domestic septage does
not include liquid or solid material
removed from a septic tank, cesspool, or
similar treatment works that receives
either commercial wastewater or
industrial wastewater and does not
include grease removed from a grease
trap at a restaurant.
(g) Domestic sewage is waste and
wastewater from humans or household
operations that is discharged to or
otherwise enters a treatment works.
(h) Dry weight basis means calculated
on the basis of having been dried at 105
degrees Celsius until reaching a
constant mass (i.e., essentially 100
percent solids content).
(i) EPA means the United States
Environmental Protection Agency.
(j) Feed crops are crops produced
primarily for consumption by animals.
(k) Fiber crops are crops such as flax
and cotton.
(1) Food crops are crops consumed by
humans. These include, but are not
limited to, fruits, vegetables, and
tobacco.
(m) Ground water is water below the
land surface in the saturated zone.
(n) Industrial wastewater is
wastewater generated in a commercial
or industrial process.
(o) Municipality means a city, town/
borough, county, parish, district,
association, or other public body
(including an intermunicipal Agency of
two or more of the foregoing entities)
created by or under State law; an Indian
tribe or an authorized Indian tribal
organization having jurisdiction over
sewage sludge management; or a
designated and approved management
Agency under section 208 of the CWA,
as amended. The definition includes a
special district created under State law,
such as a water district, sewer district,
sanitary district, utility district, drainage
district, or similar entity, or an
integrated waste management facility as
defined in section 201(e) of the CWA, as
amended, that has as one of its principal
responsibilities the treatment, transport,
use, or disposal of sewage sludge.
(p) Permitting authority is either EPA
or a State with an EPA-approved sludge
management program.
(q) Person is an individual,
association, partnership, corporation,
municipality, State or Federal agency, or
an agent or employee thereof.
(r) Person who prepares sewage
sludge is either the person who
generates sewage sludge during the
treatment of domestic sewage in a
treatment works or the person who
derives a material from sewage sludge.
(s) Place sewage sludge or sewage
sludge placed means disposal of sewage
sludge on a surface disposal site.
(t) Pollutant is an organic substance,
an inorganic substance, a combination
of organic and inorganic substances, or
a pathogenic organism that, after
discharge and upon exposure, ingestion,
inhalation, or assimilation into an
organism either directly from the
environment or indirectly by ingestion
through the food chain, could, on the
basis of information available to the
Administrator of EPA, cause death,
disease, behavioral abnormalities,
cancer, genetic mutations, physiological
malfunctions (including malfunction in
reproduction), or physical deformations
in either organisms or offspring of the
organisms.
(u) Pollutant limit is a numerical
value that describes the amount of a
pollutant allowed per unit amount of
sewage sludge (e.g., milligrams per
kilogram of total solids); the amount of
a pollutant that can be applied to a unit
area of land (e.g., kilograms per hectare);
or the volume of a material that can be
-------
9390 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
applied to a unit area of land (e.g.,
gallons per acre).
(v) Runoff is rainwater, leachate, or
other liquid that drains overland on any
part of a land surface and runs off of the
land surface.
(w) Sewage sludge is solid, semi-solid,
or liquid residue generated during the
treatment of domestic sewage in a
treatment works. Sewage sludge
includes, but is not limited to, domestic
soptago; scum or solids removed in
primary, secondary, or advanced
wostowater treatment processes; and a
material derived from sewage sludge.
Sewage sludge does not include ash
generated during the firing of sewage
sludge in a sewage sludge incinerator or
grit and screenings generated during
preliminary treatment of domestic
sewage in a treatment works.
(x) State is one of the United States of
America, the District of Columbia, the
Commonwealth of Puerto Rico, the
Virgin Islands, Guam, American Samoa,
the Trust Territory of the Pacific Islands,
the Commonwealth of the Northern
Mariana Islands, and an Indian Tribe
eligible for treatment as a State pursuant
to regulations promulgated under the
authority of section 518(e) of the CWA.
(y) Store or storage of sewage sludge
is the placement of sewage sludge on
land on which the sewage sludge
remains for two years or less. This does
not include the placement of sewage
sludge on land for treatment.
(z) Treat or treatment of sewage
sludge is the preparation of sewage
sludge for final use or disposal. This
includes, but is not limited to,
thickening, stabilization, and
dewatering of sewage sludge. This does
not include storage of sewage sludge.
(aa) Treatment works is either a
federally owned, publicly owned, or
privately owned device or system used
to treat (including recycle and reclaim)
either domestic sewage or a
combination of domestic sewage and
industrial waste of a liquid nature.
(bb) Wetlands means those areas that
are inundated or saturated by surface
water or ground water at a frequency
and duration to support, and that under
normal circumstances do support, a
prevalence of vegetation typically
adapted for life in saturated soil
conditions. Wetlands generally include
swamps, marshes, bogs, and similar
areas.
Subpart B—Land Application
§503.10 Applicability.
(a) This subpart applies to any person
who prepares sewage sludge that is
applied to the land, to any person who
applies sewage sludge to the land, to
sewage sludge applied to the land, and
to the land on which sewage sludge is
applied.
(b)(l) Bulk sewage sludge. The general
requirements in § 503.12 and the
management practices in § 503.14 do
not apply when bulk sewage sludge is
applied to the land if the bulk sewage
sludge meets the pollutant
concentrations in §503.13(b)(3), the
Class A pathogen requirements in
§ 503.32(a), and one of the vector
attraction reduction requirements in
§ 503.33 (b)(l) through (b)(8).
(2) The Regional Administrator of
EPA or, in the case of a State with an
approved sludge management program,
the State Director, may apply any or all
of the general requirements in § 503.12
and the management practices in
§ 503.14 to the bulk sewage sludge in
§ 503.10(b)(l) on a case-by-case basis
after determining that the general
requirements or management practices
are needed to protect public health and
the environment from any reasonably
anticipated adverse effect that may
occur from any pollutant in the bulk
sewage sludge.
(c)(l) The general requirements in
§ 503.12 and the management practices
in § 503.14 do not apply when a bulk
material derived from sewage sludge is
applied to the land if the derived bulk
material meets the pollutant
concentrations in § 503.13(b)(3), the
Class A pathogen requirements in
§503.32(a), and one of the vector
attraction reduction requirements in
§503.33 (b)(l) through (b)(8).
(2) The Regional Administrator of
EPA or, in the case of a State with an
approved sludge management program,
the State Director, may apply any or all
of the general requirements in § 503.12
or the management practices in § 503.14
to the bulk material in § 503.10(c)(l) on
a case-by-case basis after determining
that the general requirements or
management practices are needed to
protect public health and the
environment from any reasonably
anticipated adverse effect that may
occur from any pollutant in the bulk
sewage sludge.
(d) The requirements in this subpart
do not apply when a bulk material
derived from sewage sludge is applied
to the land if the sewage sludge from
which the bulk material is derived
meets the pollutant concentrations in
§ 503.13(b)(3), the Class A pathogen
requirements in § 503.32(a), and one of
the vector attraction reduction
requirements in §503.33 (b)(l) through
requirements in § 503.12 and the
management practices in § 503.14 do
not apply when sewage sludge is sold or
given away in a bag or other container
for application to the land if the sewage
sludge sold or given away in a bag or
other container for application to the
land meets the pollutant concentrations
in § 503.13(b)(3), the Class A pathogen
requirements in § 503.32(a), and one of
the vector attraction reduction
requirements in § 503.33 (b)(l) through
(e) Sewage sludge sold or given away
in a bag or other container for
application to the land. The general
(f) The general requirements in
§ 503.12 and the management practices
in § 503.14 do not apply when a
material derived from sewage sludge is
sold or given away in a bag or other
container for application to the land if
the derived material meets the pollutant
concentrations in § 503.13(b)(3), the
Class A pathogen requirements in
§ 503.32(a), and one of the vector
attraction reduction requirements in
§ 503.33 (b)(l) through (b)(8).
(g) The requirements in this subpart
do not apply when a material derived
from sewage sludge is sold or given
away in a bag or other container for
application to the land if the sewage
sludge from which the material is
derived meets the pollutant
concentrations in § 503.13(b)(3), the
Class A pathogen requirements in
§ 503.32(a), and one of the vector
attraction reduction requirements in
§ 503.33 (b)(l) through (b)(8).
§ 503.1 1 Special definitions.
(a) Agricultural land is land on which
a food crop, a feed crop, or a fiber crop
is grown. This includes range land and
land used as pasture.
(b) Agronomic rate is the whole
sludge application rate (dry weight
basis) designed:
(1) To provide the amount of nitrogen
needed by the food crop, feed crop, fiber
crop, cover crop, or vegetation grown on
the land; and
(2) To minimize the amount of
nitrogen in the sewage sludge that
passes below the root zone of the crop
or vegetation grown on the land to the
ground water.
(c) Annual pollutant loading rate is
the maximum amount of a pollutant that
can be applied to a unit area of land
during a 365 day period.
(d) Annual whole sludge application
rate is the maximum amount of sewage
sludge (dry weight basis) that can be
applied to a unit area of land during a
365 day period.
(e) Bulk sewage sludge is sewage
sludge that is not sold or given away in
a bag or other container for application
to the land.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9391
(f) Cumulative pollutant loading rate
is the maximum amount of an inorganic
pollutant that can be applied to an area
of land.,
(g) Forest is a tract of land thick with
trees and underbrush.
(h) Land application is the spraying or
spreading of sewage sludge onto the
land surface; the injection of sewage
sludge below the land surface; or the
incorporation of sewage sludge into the
soil so that the sewage sludge can either
condition the soil or fertilize crops or
vegetation grown in the soil.
(1) Monthly average is the arithmetic
mean of all measurements taken during
the month.
(j) Other container is either an open
or closed receptacle. This includes, but
is not limited to, a bucket, a box, a
carton, and a vehicle or trailer with a
load capacity of one metric ton or less.
(k) Pasture is land on which animals
feed directly on feed crops such as
legumes, grasses, grain stubble, or
stover.
(1) Public contact site is land with a
high potential for contact by the public.
This includes, but is not limited to,
public parks, ball fields, cemeteries,
plant nurseries, turf farms, and golf
courses.
(m) Range land is open land with
indigenous vegetation.
(n)Reclamation site is drastically
disturbed land that is reclaimed using
sewage sludge. This includes, but is not
limited to, strip mines and construction
sites.
§503.12 General requirements.
(a) No person shall apply sewage
sludge to the land except in accordance
with the requirements in this subpart.
(b) No person shall apply bulk sewage
sludge subject to the cumulative
pollutant loading rates in § 503.13(b)(2)
to agricultural land, forest, a public
contact site, or a reclamation site if any
of the cumulative pollutant loading
rates in § 503.13(b)(2) has been reached.
(c) No person shall apply domestic
septage to agricultural land, forest, or a
reclamation site during a 365 day period
if the annual application rate in
§ 503.13(c) has been reached during that
period.
(d) The person who prepares bulk
sewage sludge that is applied to
agricultural land, forest, a public contact
site, or a reclamation site shall provide
the person who applies the bulk sewage
sludge written notification of the
concentration of total nitrogen (as N on
a dry weight basis) in the bulk sewage
sludge.
(e)(l) The person who applies sewage
sludge to the land shall obtain
information needed to comply with the
requirements in this subpart.
(2)(i) Before bulk sewage sludge
subject to the cumulative pollutant
loading rates in § 503.13(b)(2) is applied
to the land, the person who proposes to
apply the bulk sewage sludge shall
contact the permitting authority for the
State in which the bulk sewage sludge
will be applied to determine whether
bulk sewage sludge subject to the
cumulative pollutant loading rates in
§ 503.13(b)(2) has been applied to the
site since July 20, 1993.
(ii) If bulk sewage sludge subject to
the cumulative pollutant loading rates
in § 503.13(b)(2) has not been applied to
the site since July 20,1993, the
cumulative amount for each pollutant
listed in Table 2 of § 503.13 may be
applied to the site in accordance with
§ 503.13(a)(2)(i).
(iii) If bulk sewage sludge subject to
the cumulative pollutant loading rates
in § 503.13(b)(2) has been applied to the
site since July 20, 1993, and the
cumulative amount of each pollutant
applied to the site in the bulk sewage
sludge since that date is known, the
cumulative amount of each pollutant
applied to the site shall be used to
determine the additional amount of
each pollutant that can be applied to the
site in accordance with § 503.13(a)(2)(i).
(iv) If bulk sewage sludge subject to
the cumulative pollutant loading rates
in § 503.13(b)(2) has been applied to the
site since July 20,1993, and the
cumulative amount of each pollutant
applied to the site in the bulk sewage
sludge since that date is not known, an
additional amount of each pollutant
shall not be applied to the site in
accordance with §503.13{a)(2)(i).
(f) When a person who prepares bulk
sewage sludge provides the bulk sewage
sludge to a person who applies the bulk
sewage sludge to the land, the person
who prepares the bulk sewage sludge
shall provide the person who applies
the sewage sludge notice and necessary
information to comply with the
requirements in this subpart.
(g) When a person who prepares
sewage sludge provides the sewage
sludge to another person who prepares
the sewage sludge, the person who
provides the sewage sludge shall
provide the person who receives the
sewage sludge notice and necessary
information to comply with the
requirements in this subpart.
(n) The person who applies bulk
sewage sludge to the land shall provide
the owner or lease holder of the land on
which the bulk sewage sludge is applied
notice and necessary information to
comply with the requirements in this
subpart.
(ij Any person who prepares bulk
sewage sludge that is applied to land in
a State other than the State in which the
bulk sewage sludge is prepared shall
provide written notice, prior to the
initial application of bulk sewage sludge
to the land application site by the
applier, to the permitting authority for
the State in which the bulk sewage
sludge is proposed to be applied. The
notice shall include:
(1) The location, by either street
address or latitude and longitude, of
each land application site.
(2) The approximate time period bulk
sewage sludge will be applied to the
site.
(3) The name, address, telephone
number, and National Pollutant
Discharge Elimination System permit
number (if appropriate) for the person
who prepares the bulk sewage sludge.
(4) The name, address, telephone
number, and National Pollutant
Discharge Elimination System permit
number (if appropriate) for the person
who will apply the bulk sewage sludge.
(j) Any person who applies bulk
sewage sludge subject to the cumulative
pollutant loading rates in §503.13(b)(2)
to the land shall provide written notice,
prior to the initial application of bulk
sewage sludge to a land application site
by the applier, to the permitting
authority for the State in which the bulk
sewage sludge will be applied and the
permitting authority shall retain and
provide access to the notice. The notice
shall include:
(1) The location, by either street
address or latitude and longitude, of the
land application site.
(2) The name, address, telephone
number, and National Pollutant
Discharge Elimination System permit
number (if appropriate) of the person
who will apply the bulk sewage sludge.
§503.13 Pollutant limits.
(a) Sewage sludge. (1) Bulk sewage
sludge or sewage sludge sold or given
away in a bag or other container shall
not be applied to the land if the
concentration of any pollutant in the
sewage sludge exceeds the ceiling
concentration for the pollutant in Table
1 of §503.13.
(2) If bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site, either:
(i) The cumulative loading rate for
each pollutant shall not exceed the
cumulative pollutant loading rate for the
pollutant in Table 2 of § 503.13; or
(ii) The concentration of each
pollutant in the sewage sludge shall not
exceed the concentration for the
pollutant in Table 3 of § 503.13.
(3) If bulk sewage sludge is applied to
a lawn or a home garden, the
concentration of each pollutant in the
-------
9392 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sowogo sludge shall not exceed the
concentration for the pollutant in Table
3 of §503.13.
(4) If sewage sludge is sold or given
away in a bag or other container for
application to the land, either:
(i) The concentration of each
pollutant in the sewage sludge shall not
exceed the concentration for the
pollutant in Table 3 of § 503.13; or
(ii) The product of the concentration
of each pollutant in the sewage sludge
and the annual whole sludge
application rate for the sewage sludge
shall not cause the annual pollutant
loading rate for the pollutant in Table 4
of § 503.13 to be exceeded. The
procedure used to determine the annual
whole sludge application rate is
presented in appendix A of this part.
(b) Pollutant concentrations and
loading rates—sewage sludge.
(1) Ceiling concentrations.
TABLE 1 OF §503.13.—CEILING
CONCENTRATIONS
TABLE 3 OF §503.13.—POLLUTANT
CONCENTRATIONS—Continued
Pollutant
Arsook:
Cadmium
Chromium
Coppor .«........*... . .... .
Mercury „..„..„,..,...,....,....
Molybdenum ....................
Ntekal
Selenium
2loe „.„..„ „
Celling concentration
(milligrams per kilo-
gram)1
75
85
3000
4300
840
57
75
420
100
7500
'Dry weight basis.
(2) Cumulative pollutant loading
rates.
TABLE 2 OF §503.13.—CUMULATIVE
POLLUTANT LOADING RATES
Pollutant
Arsonks
Cadmium
Chromium
Copper
Load „
Morcury ..................... ..,..
Motytxtonum
NtcXol ,^.™,..TO,,n
Setonium
23oc „
Cumulative pollutant
loading rate (kilograms
per hectare)
41
39
3000
1500
300
17
18
420
100
2800
(3) Pollutant concentrations.
TABLE 3 OF §503.13.—POLLUTANT
CONCENTRATIONS
Pollutant
Arsenic
Cadmium
Chromium ...„
Copper
Monthly average con-
centrations (milligrams
per kilogram) '
41
39
1200
1500
Pollutant
Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc
Monthly average con-
centrations (milligrams
per kilogram) 1
300
17
18
420
36
2800
1 Dry weight basis.
(4) Annual pollutant loading rates.
TABLE 4 OF §503.13.—ANNUAL
POLLUTANT LOADING RATES
Pollutant
Arsenic
Cadmium
Chromium
CoDoer . .
Lead
Mercury
Molybdenum
Nickel
Selenium ... .
Zinc
Annual pollutant loading
rate (kilograms per hec-
tare per 365 day period)
2.0
1 9
150
75
15
085
090
21
50
140
(c) Domestic septage.
The annual application rate for
domestic septage applied to agricultural
land, forest, or a reclamation site shall
not exceed the annual application rate
calculated using equation (1).
N
AAR= Eq. (1)
0.0026
Where:
AAR=Annual application rate in gallons per
acre per 365 day period.
N=Amount of nitrogen in pounds per acre
per 365 day period needed by the crop
or vegetation grown on the land.
§503.14 Management practices.
(a) Bulk sewage sludge shall not be
applied to the land if it is likely to
adversely affect a threatened or
endangered species listed under section
4 of the Endangered Species Act or its
designated critical habitat.
(b) Bulk sewage sludge shall not be
applied to agricultural land, forest, a
public contact site, or a reclamation site
that is flooded, frozen, or snow-covered
so that the bulk sewage sludge enters a
wetland or other waters of the United
States, as defined in 40 CFR 122.2,
except as provided in a permit issued
pursuant to section 402 or 404 of the
CWA.
(c) Bulk sewage sludge shall not be
applied to agricultural land, forest, or a
reclamation site that is 10 meters or less
from waters of the United States, as
defined in 40 CFR 122.2, unless
otherwise specified by the permitting
authority.
(d) Bulk sewage sludge shall be
applied to agricultural land, forest, a
public contact site, or a reclamation site
at a whole sludge application rate that
is equal to or less than the agronomic
rate for the bulk sewage sludge, unless,
in the case of a reclamation site,
otherwise specified by the permitting
authority.
(e) Either a label shall be affixed to the
bag or other container in which sewage
sludge that is sold or given away for
application to the land, or an
information sheet shall be provided to
the person who receives sewage sludge
sold or given away in an other container
for application to the land. The label or
information sheet shall contain the
following information:
(1) The name and address of the
person who prepared the sewage sludge
that is sold or given away in a bag or
other container for application to the
land.
(2) A statement that application of the
sewage sludge to the land is prohibited
except in accordance with the
instructions on the label or information
sheet.
(3) The annual whole sludge
application rate for the sewage sludge
that does not cause any of the annual
pollutant loading rates in Table 4 of
§ 503.13 to be exceeded.
§503.15 Operational standards—
pathogens and vector attraction reduction.
(a) Pathogens—sewage sludge.
(1) The Class A pathogen
requirements in § 503.32(a) or the Class
B pathogen requirements and site
restrictions in § 503.32(b) shall be met
when bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site.
(2) The Class A pathogen
requirements in § 503.32(a) shall be met
when bulk sewage sludge is applied to
a lawn or a home garden.
(3) The Class A pathogen
requirements in § 503.32(a) shall be met
when sewage sludge is sold or given
away in a bag or other container for
application to the land.
(b) Pathogens—domestic septage.
The requirements in either § 503.32
(c)(l) or (c)(2) shall be met when
domestic septage is applied to
agricultural land, forest, or a
reclamation site.
(c) Vector attraction reduction—
sewage sludge.
(1) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(10) shall be met when
bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9393
(2) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(8) shall be met when
bulk sewage sludge is applied to a lawn
or a home garden.
(3) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(8) shall be met when
sewage sludge is sold or given away in
a bag or other container for application
to the land.
(d) Vector attraction reduction—
domestic septage. The vector attraction
reduction requirements in
§ 503.33(b)(9), (b)(10), or (b)(12) shall be
met when domestic septage is applied to
agricultural land, forest, or a
reclamation site.
§ 503.16 Frequency of monitoring.
(a) Sewage sludge. (1) The frequency
of monitoring for the pollutants listed in
Table 1, Table 2, Table 3 and Table 4
of § 503.13; the pathogen density
requirements in § 503.32(a) and in
§ 503.32(b)(2) through (b)(4); and the
vector attraction reduction requirements
§ 503.33 (b)(l) through § 503.33(b)(8)
shall be the frequency in Table 1 of
§503.16.
TABLE. 1 OF §503.16.—FREQUENCY OF
MONITORING—LAND APPLICATION
Amount of sewage
sludge1 (metric tons per
365 day period)
Greater than zero but
less than 290.
Equal to or greater than
290 but less than
1,500.
Equal to or greater than
1,500 but less than
15,000.
Equal to or greater than
15,000.
Frequency
Once per year.
Once per quarter (four
times per year).
Once per 60 days (six
times per year).
Once per month (12
times per year).
1 Either the amount of bulk sewage sludge applied
to the land or the amount of sewage sludge received
by a person who prepares sewage sludge that is
sold or given away in a bag or other container for
application to the land (dry weight basis).
(2) After the sewage sludge has been
monitored for two years at the frequency
in Table 1 of § 503.16, the permitting
authority may reduce the frequency of
monitoring for pollutant concentrations
and for the pathogen density
requirements in § 503.32 [a)(5)(ii) and
(a)(5)(iii), but in no case shall the
frequency of monitoring be less than
once per year when sewage sludge is
applied to the land.
(b) Domestic septage. If either the
pathogen requirements in § 503.32(c){2)
or the vector attraction reduction
requirements in § 503.33(b)(12) are met
when domestic septage is applied to
agricultural land, forest, or a
reclamation site, each container of
domestic septage applied to the land
shall be monitored for compliance with
those requirements.
(Approved by the Office of Management and
Budget under control number 2040-0157)
§503.17 Recordkeeping.
(a) Sewage sludge. (1) The person who
prepares the sewage sludge in
§ 503.10(b)(l) or (e) shall develop the
following information and shall retain
the information for five years:
(i) The concentration of each
pollutant listed in Table 3 of § 503.13 in
the sewage sludge.
(ii) The following certification
statement:
"I certify, under penalty of law, that the
Class A pathogen requirements in § 503.32(a)
and the vector attraction reduction
requirement in [insert one of the vector
attraction reduction requirements in
§ 503.33(b)(l) through § 503.33(b)(8)] have
been met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the pathogen requirements
and vector attraction reduction requirements
have been met. I am aware that there are
significant penalties for false certification
including the possibility of fine and
imprisonment."
(iii) A description of how the Class A
pathogen requirements in § 503.32(a) are
met.
(iv) A description of how one of the
vector attraction reduction requirements
in § 503.33 (b)(l) through (b)(8) is met.
(2) The person who derives the
material in § 503.10 (c)(l) or (f) shall
develop the following information and
shall retain the information for five
years:
(i) The concentration of each
pollutant listed in Table 3 of § 503.13 in
the material.
(ii) The following certification
statement:
"I certify, under penalty of law, that the
Class A pathogen requirements in § 503.32(a)
and the vector attraction reduction
requirement in [insert one of the vector
attraction reduction requirements in § 503.33
(b)(l) through (b)(8)l have been met. This
determination has been made under my
direction and supervision in accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
pathogen requirements and the vector
attraction reduction requirements have been
met. I am aware that there are significant
penalties for false certification including the
possibility of fine and imprisonment."
(iii) A description of how the Class A
pathogen requirements in § 503.32(a) are
met.
(iv) A description of how one of the
vector attraction reduction requirements
in § 503.33 (b)(l) through (b)(8) is met.
(3) If the pollutant concentrations in
§ 503.13(b)(3), the Class A pathogen
requirements in § 503.32(a), and the
vector attraction reduction requirements
in either § 503.33 (b)(9) or (b)(10) are
met when bulk sewage sludge is applied
to agricultural land, forest, a public
contact site, or a reclamation site:
(i) The person who prepares the bulk
sewage sludge shall develop the
following information and shall retain
the information for five years.
(A) The concentration of each
pollutant listed in Table 3 of § 503.13 in
the bulk sewage sludge.
(B) The following certification
statement:
"I certify, under penalty of law, that the
pathogen requirements in § 503.32(a) have
been met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the pathogen requirements
have been met. I am aware that there are
significant penalties for false certification
including the possibility of fine and
imprisonment."
(C) A description of how the pathogen
requirements in § 503.32(a) are met.
(ii) The person who applies the bulk
sewage sludge shall develop the
following information and shall retain
the information for five years.
(A) The following certification
statement:
"I certify, under penalty of law, that the
management practices in § 503.14 and the
vector attraction reduction requirement in
[insert either § 503.33 (b)(9) or (b)(10)] have
been met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the management practices and
vector attraction reduction requirements have
been met. I am aware that there are
significant penalties for false certification
including fine and imprisonment."
(B) A description of how the
management practices in § 503.14 are
met for each site on which bulk sewage
sludge is applied.
(C) A description of how the vector
attraction reduction requirements in
either § 503.33(b)(9) or (b)(10) are met
for each site on which bulk sewage
sludge is applied.
(4) If the pollutant concentrations in
§ 503.13(b)(3) and the Class B pathogen
requirements in § 503.32(b) are met
when bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site:
(i) The person who prepares the bulk
sewage sludge shall develop the
following information and shall retain
the information for five years:
-------
9394 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(A) Tho concentration of each
pollutant listed in Table 3 of §503.13 in
the bulk sewage sludge.
(B) The following certification
statement:
"1 certify under, penalty of law, that the
Class B pathogen requirements in § 503.32(b)
and (ho vector attraction reduction
requirement in (insert one of the vector
attraction reduction requirements in § 503.33
(b)(l) through (b)(8) if one of those
requirements is mot] have been met. This
determination has boon made under my
direction and supervision In accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
Information used to determine that the
pathogen requirements [and vector attraction
reduction requirements if applicable] have
boon mot. I am aware that there are
significant penalties for false certification
Including the possibility of fine and
imprisonment."
(C) A description of how the Class B
pathogen requirements in § 503.32(b)
are mot.
(D) When one of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(8) is met, a description
of ho\v the vector attraction reduction
requirement is met.
lii) The person who applies the bulk
sewago sludge shall develop the
following information and shall retain
the information for five years.
(A) The following certification
statement:
"1 certify, under penalty of law, that the
management practices in § 503.14, the site
restrictions in § 503.32(b)(5), and the vector
attraction reduction requirements in [insert
cither §503.33 (b){9) or(b)(10), if one of those
requirements is met] have been met for each
silo on which bulk sewage sludge is applied.
This determination has been made under my
direction and supervision in accordance with
tho system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
management practices and site restrictions
{and the vector attraction reduction
requirements if applicable] have been met. I
am aware that there are significant penalties
for false certification including the
possibility of fine and imprisonment."
(B) A description of how the
management practices in § 503.14 are
met for each site on which bulk sewage
sludge is applied.
(C) A description of how the site
restrictions in § 503.32(b)(5) are met for
each site on which bulk sewage sludge
is applied.
(D) When the vector attraction
reduction requirement in either § 503.33
(b)(9) or (b)(10) is met, a description of
how the vector attraction reduction
requirement is met.
(5) If the requirements in
§ 503.13(a)(2)(i) are met when bulk
sowago sludge is applied to agricultural
land, forest, a public contact site, or a
reclamation site:
(i) The person who prepares the bulk
sewage sludge shall develop the
following information and shall retain
the information for five years.
(A) The concentration of each
pollutant listed in Table 1 of § 503.13 in
the bulk sewage sludge.
(B) The following certification
statement:
"I certify, under penalty of law, that the
pathogen requirements in [insert either
§ 503.32(a) or § 503.32(b)J and the vector
attraction reduction requirement in [insert
one of the vector attraction reduction
requirements in § 503.33 (b)(l) through (b)(8)
if one of those requirements is met] have
been met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the pathogen requirements
[and vector attraction reduction
requirements] have been met. I am aware that
there are significant penalties for false
certification including the possibility of fine
and imprisonment."
(C) A description of how the pathogen
requirements in either § 503.32 (a) or (b)
are met.'
(D) When one of the vector attraction
requirements in §503.33 (b)(l) through
(b)(8) is met, a description of how the
vector attraction requirement is met.
(ii) The person who applies the bulk
sewage sludge shall develop the
following information, retain the
information in § 503.17 (a)(5)(ii)(A)
through (a)(5)(ii)(G) indefinitely, and
retain the information in § 503.17
(a)(5)(ii)(H) through (a)(5)(ii)(M) for five
years.
(A) The location, by either street
address or latitude and longitude, of
each site on which bulk sewage sludge
is applied.
(B) The number of hectares in each
site on which bulk sewage sludge is
applied.
(C) The date and time bulk sewage
sludge is applied to each site.
(D) The cumulative amount of each
pollutant (i.e., kilograms) listed in Table
2 of § 503.13 in the bulk sewage sludge
applied to each site, including the
amount in §503.12(e)(2)(iii).
(E) The amount of sewage sludge (i.e.,
metric tons) applied to each site.
(F) The following certification
statement:
"I certify, under penalty of law, that the
requirements to obtain information in
§ 503.12(e)(2) have been met for each site on
which bulk sewage sludge is applied. This
determination has been made under my
direction and supervision in accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
requirements to obtain information have been
met. I am aware that there are significant
penalties for false certification including fine
and imprisonment."
(G) A description of how the
requirements to obtain information in
§ 503.12(e)(2) are met.
(H) The following certification
statement:
"I certify, under penalty of law, that the
management practices in § 503.14 have been
met for each site on which bulk sewage
sludge is applied. This determination has
been made under my direction and
supervision in accordance with the system
designed to ensure that qualified personnel
properly gather and evaluate the information
used to determine that the management
practices have been met. I am aware that
there are significant penalties for false
certification including fine and
imprisonment."
(I) A description of how the
management practices in § 503.14 are
met for each site on which bulk sewage
sludge is applied.
(J) The following certification
statement when the bulk sewage sludge
meets the Class B pathogen
requirements in § 503.32(b):
"I certify, under penalty of law, that the
site restrictions in § 503.32(b)(5) have been
met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the site restrictions have been
met. I am aware that there are significant
penalties for false certification including fine
and imprisonment."
(K) A description of how the site
restrictions in § 503.32(b)(5) are met for
each site on which Class B bulk sewage
sludge is applied.
(L) The following certification
statement when the vector attraction
reduction requirement in either § 503.33
(b)(9) or (b)(10) is met:
"I certify, under penalty of law, that the
vector attraction reduction requirement in
[insert either § 503.33(b)(9) or § 503.33(b)(10)]
has been met. This determination has been
made under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the vector attraction reduction
requirement has been met. I am aware that
there are significant penalties for false
certification including the possibility of fine
and imprisonment."
(M) If the vector attraction reduction
requirements in either § 503.33 (b)(9) or
(b)(10) are met, a description of how the
requirements are met.
(6) If the requirements in
§ 503.13(a)(4)(ii) are met when sewage
sludge is sold or given away in a bag or
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9395
other container for application to the
land, the person who, prepares the
sewage sludge that is sold or given away
in a bag or other container shall develop
the following information and shall
retain the information for five years:
(i) The annual whole sludge
application rate for the sewage sludge
that does not cause the annual pollutant
loading rates in Table 4 of § 503.13 to
be exceeded.
(ii) The concentration of each
pollutant listed in Table 4 of § 503.13 in
the sewage sludge.
(iii) The following certification
statement:
"I certify, under penalty of law, that the
management practice in § 503.14(e), the Class
A pathogen requirement in § 503.32(a), arid
the vector attraction reduction requirement
in [insert one of the vector attraction
reduction requirements in § 503.33 (b)(l)
through (b)(8)] have been met. This
determination has been made under my
direction and supervision in accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
management practice, pathogen
requirements, and vector attraction reduction
requirements have been met. I am aware that
there are significant penalties for false
certification including the possibility of fine
and imprisonment."
(iv) A description of how the Class A
pathogen requirements in § 503.32(a) are
met.
(v) A description of how one of the
vector attraction requirements in
§ 503.33 (b)(l) through (b)(8) is met.
(b) Domestic septage. When domestic
septage is applied to agricultural land,
forest, or a reclamation site, the person
who applies the domestic septage shall
develop the following information and
shall retain the information for five
years:
(1) The location, by either street
address or latitude and longitude, of
each site on which domestic septage is
applied.
(2) The number of acres in each site
on which domestic septage is applied.
(3) The date and time domestic
septage is applied to each site.
(4) The nitrogen requirement for the
crop or vegetation grown on each site ,
during a 365 day period.
(5) The rate, in gallons per acre per
365 day period, at which domestic
septage is applied to each site.
(6) The following certification
statement:
"I certify, under penalty of law, that the
pathogen requirements in [insert either
§ 503.32(c)(l) or § 503.32(c)(2)] and the vector
attraction reduction requirements in [insert
§ 503.33(b)(9), § 503.33(b)(10), or
§ 503.33(b)(12)] have been met. This
determination has been made under my
direction and supervision in accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
pathogen requirements and vector attraction
reduction requirements have been met. I am
aware that there are significant penalties for
false certification including the possibility of
fine and imprisonment."
(7) A description of how, the pathogen
requirements in either § 503.33 (c)(l) or
(c)(2) are met.
(8) A description of how the vector
attraction reduction requirements in
§503.33 (b){9), (b)(10), or (b)(12) are
met.
(Approved by the.Office of Management and
Budget under control number 2040-0157)
§503.18 Reporting.
(a) Class I sludge management
facilities, POTWs (as defined in 40 CFR
501.2) with a design flow rate equal to
or greater than one million gallons per
day, and POTWs that serve 10,000
people or more shall submit the
following information to the permitting
authority:
(1) The information in § 503.17(a),
except the information in § 503.17
(a)(3)(ii), (a)(4)(ii) and in (a)(5)(ii), for
the appropriate requirements on
February 19 of each year.
(2) The information in § 503.17
(a)(5)(ii)(A) through (a)(5)(ii)(G) on
[insert the month and day from the date
of publication of this rule] of each year
when 90 percent or more of any of the
cumulative pollutant loading rates in
Table 2 of § 503.13 is reached at a site.
(Approved by the Office of Management and
Budget under control number 2040-0157}
Subpart C—Surface Disposal
§503.20 Applicability.
(a) This subpart applies to any person
who prepares sewage sludge that is
placed on a surface disposal site, to the
owner/operator of a surface disposal
site, to sewage sludge placed on a
surface disposal site, and to a surface
disposal site.
(b) This subpart does not apply to
sewage sludge stored on the land or to
the land on which sewage sludge is
stored. It also does not apply to sewage
sludge that remains oh the land for
longer than two years^when the person
who prepares the sewage sludge
demonstrates that the, land on which the
sewage sludge remains is not an active
sewage sludge unit. The demonstration
shall include the following information,
which shall be retained by the person
who prepares the sewage sludge for the
period that the sewage sludge remains
on the land:
(1) The name and address of the
person who prepares the sewage sludge.
(2) The name and address of the
person who either owns the land or
leases the land.
(3) The location, by either street
address or latitude and longitude, of the
land.
(4) An explanation of why sewage
sludge needs to remain on the land for
longer than two years prior to final use
or disposal.
(5) The approximate time period
when the sewage sludge will be used or
disposed.
(c) This subpart does not apply to
sewage sludge treated on the land or to
the land on which sewage sludge is
treated.
§503.21 Special definitions.
(a) Active sewage sludge unit is a
sewage sludge unit that has not closed.
(b) Aquifer is a geologic formation,
group of geologic formations, or a
portion of a geologic formation capable
of yielding ground water to wells or
springs.
(c) Contaminate an aquifer means to
introduce a substance that causes the
maximum contaminant level for nitrate
in 40 CFR 141.11 to be exceeded in
ground water or that causes the existing
concentration of nitrate in ground water
to increase when the existing
concentration of nitrate in the ground
water exceeds the maximum
contaminant level for nitrate in 40 CFR
141.11.
(d) Cover is soil or other material used
to cover sewage sludge placed on an
active sewage sludge unit.
(e) Displacement is the relative
movement of any two sides of a fault
measured in any direction.
(f) Fault is a fracture or zone of
fractures in any materials along which
strata on one side are displaced with
respect to strata on the other side.
(g) Final cover is the last layer of soil
or other material placed on a sewage
sludge unit at closure.
(h) Holocene time is the most recent
epoch of the Quaternary period,
extending from the end of the
Pleistocene epoch to the present.
(i) Leachate collection system is a
system or device installed immediately
above a liner that is designed,
constructed, maintained, and operated
to collect and remove leachate from a
sewage sludge unit.
(j) Liner is soil or synthetic material
that has a hydraulic conductivity of
1x10 ~7 centimeters per second or less.
(k) Lower explosive limit for methane
gas is the lowest percentage of methane
gas in air, by volume, that piupagates a
flame at 25 degrees Celsius and
atmospheric pressure.
(1) Qualified ground-water scientist is
ah individual with a baccalaureate or
-------
9396 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
post-graduate degree in the natural
sciences or engineering who has
sufficient training and experience in
ground-water hydrology and related
fields, as may be demonstrated by State
registration, professional certification,
or completion of accredited university
programs, to make sound professional
Judgments regarding ground-water
monitoring, pollutant fate and transport,
and corrective action.
(m) Seismic impact zone is an area
that has a 10 percent or greater
probability that the horizontal ground
level acceleration of the rock in the area
exceeds 0.10 gravity once in 250 years.
(n) Sewage sludge unit is land on
which only sewage sludge is placed for
final disposal. This does not include
land on which sewage sludge is either
stored or treated. Land does not include
waters of the United States, as defined
in 40 CFR 122.2.
(o) Sewage sludge unit boundary is
the outermost perimeter of an active
sowogo sludge unit.
(p) Surface disposal site is an area of
land that contains one or more active
sowage sludge units.
(q) Unstable area is land subject to
natural or human-induced forces that
may damage the structural components
of an active sewage sludge unit. This
includes, but is not limited to, land on
which the soils are subject to mass
movement.
§503.22 General requirements.
(a) No person shall place sewage
sludge on an active sewage sludge unit
unless the requirements in this subpart
are met.
(b) An active sewage sludge unit
located within 60 meters of a fault that
has displacement in Holocene time;
located in an unstable area; or located
in a wetland, except as provided in a
permit issued pursuant to section 402 of
the CWA, shall close by [insert date one
year after the effective date of this Final
rule], unless, in the case of an active
sowage sludge unit located within 60
meters of a fault that has displacement
in Holocene time, otherwise specified
by the permitting authority.
(c) The owner/operator of an active
sewage sludge unit shall submit a
written closure and post closure plan to
the permitting authority 180 days prior
to the date that the active sewage sludge
unit closes. The plan shall describe how
the sewage sludge unit will be closed
and, at a minimum, shall include:
(1) A discussion of how the leachate
collection system will be operated and
maintained for three years after the
sowage sludge unit closes if the sewage
sludge unit has a liner and leachate
collection system.
(2) A description of the system used
to monitor for methane gas in the air in
any structures within the surface
disposal site and in the air at the
property line of the surface disposal
site, as required in § 503.24(j)(2).
(3) A discussion of how public access
to the surface disposal site will be
restricted for three years after the last
sewage sludge unit in the surface
disposal site closes.
(d) The owner of a surface disposal
site shall provide written notification to
the subsequent owner of the site that
sewage sludge was placed on the land.
§ 503.23 Pollutant limits (other than
domestic septage).
(a) Active sewage sludge unit without
a liner and leachate collection system.
(1) Except as provided in § 503.23
(a)(2) and (b), the concentration of each
pollutant listed in Table 1 of § 503.23 in
sewage sludge placed on an active
sewage sludge unit shall not exceed the
concentration for the pollutant in Table
1 of §503.23.
TABLE 1 OF §503.23.—POLLUTANT CON-
CENTRATIONS—ACTIVE SEWAGE SLUDGE
UNIT WITHOUT A LINER AND LEACHATE
COLLECTION
Pollutant
Arsenic
Chromium
Nickel
Concentration
(milligrams per
kilograms')
73
600
420
1 Dry weight basis.
(2) Except as provided in § 503.23(b),
the concentration of each pollutant
listed in Table 1 of § 503.23 in sewage
sludge placed on an active sewage
sludge unit whose boundary is less than
150 meters from the property line of the
surface disposal site shall not exceed
the concentration determined using the
following procedure.
(i) The actual distance from the active
sewage sludge unit boundary to the
property line of the surface disposal site
shall be determined.
(ii) The concentration of each
pollutant listed in Table 2 of § 503.23 in
the sewage sludge shall not exceed the
concentration in Table 2 of § 503.23 that
corresponds to the actual distance in
§ 503.23(a)(2)(i).
TABLE 2 OF § 503.23.—POLLUTANT CON-
CENTRATIONS—ACTIVE SEWAGE SLUDGE
UNIT WITHOUT A LINER AND LEACHATE
COLLECTION SYSTEM THAT HAS A UNIT
BOUNDARY TO PROPERTY LINE DIS-
TANCE LESS THAN 150 METERS
Unit boundary to
property line
Distance (meters)
0 to less than 25
25 to less than 50
50 to less than 75
75 to less than
100
100 to less than
125
125 to less than
150
Pollutant concentration '
Arsenic
(mo/kg)
30
34
39
46
53
62
Chro-
mium
(mg/kg)
200
220
260
300
360
450
Nickel
(ma/kg)
210
240
270
320
390
420
1 Dry weight basis.
(b) Active sewage sludge unit without
a liner and leachate collection system—
site-specific limits.
(1) At the time of permit application,
the owner/operator of a surface disposal
site may request site-specific pollutant
limits in accordance with § 503.23(b)(2)
for an active sewage sludge unit without
a liner and leachate collection system
when the existing values for site
parameters specified by the permitting
authority are different from the values
for those parameters used to develop the
pollutant limits in Table 1 of § 503.23
and when the permitting authority
determines that site-specific pollutant
limits are appropriate for the active
sewage sludge unit.
(2) The concentration of each
pollutant listed in Table 1 of § 503.23 in
sewage sludge placed on an active
sewage sludge unit without a liner and
leachate collection system shall not
exceed either the concentration for the
pollutant determined during a site-
specific assessment, as specified by the
permitting authority, or the existing
concentration of the pollutant in the
sewage sludge, whichever is lower.
§503.24 Management practices.
(a) Sewage sludge shall not be placed
on an active sewage sludge unit if it is
likely to adversely affect a threatened or
endangered species listed under section
4 of the Endangered Species Act or its
designated critical habitat.
(b) An active sewage sludge unit shall
not restrict the flow of a base flood.
(c) When a surface disposal site is
located in a seismic impact zone, an
active sewage sludge unit shall be
designed to withstand the 'aximum
recorded horizontal ground level
acceleration.
(d) An active sewage sludge unit shall
be located 60 meters or more from a
fault that has displacement in Holocene
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9397
time, unless otherwise specified by the
permitting authority.
(e) An active sewage sludge unit shall
not be located in an unstable area.
(f) An active sewage sludge unit shall
not be located in a wetland, except as
provided in a permit issued pursuant to
section 402 or 404 of the CWA.
(g)(l) Run-off from an active sewage
sludge unit shall be collected and shall
be disposed in accordance with
National Pollutant Discharge
Elimination System permit
requirements and any other applicable
requirements.
(2) The run-off collection system for
an active sewage sludge unit shall have
the capacity to handle run-off from a 24-
hour, 25-year storm event.
(h) The leachate collection system for
an active sewage sludge unit that has a
liner and leachate collection system
shall be operated and maintained during
the period the sewage sludge unit is
active and for three years after the
sewage sludge unit closes.
(i) Leachate from an active sewage
sludge unit that has a liner and leachate
collection system shall be collected and
shall be disposed in accordance with
the applicable requirements during the
period the sewage sludge unit is active
and for three years after the sewage
sludge unit closes.
(j)(l) When a cover is placed on an
active sewage sludge unit, the
concentration of methane gas in air in
any structure within the surface
disposal site shall not exceed 25 percent
of the lower explosive limit for methane
gas during the period that the sewage
sludge unit is active and the
concentration of methane gas in air at
the property line of the surface disposal
site shall not exceed the lower explosive
limit for methane gas during the period
that the sewage sludge unit is active.
(2) When a final cover is placed on a
sewage sludge unit at closure, the
concentration of methane gas in air in
any structure within the surface
disposal site shall not exceed 25 percent
of the lower explosive limit for methane
gas for three years after the sewage
sludge unit closes and the concentration
of methane gas in air at the property line
of the surface disposal site shall not
exceed the lower explosive limit for
methane gas for three years after the
sewage sludge unit closes, unless
otherwise specified by the permitting
authority.
(k) A food crop, a feed crop, or a fiber
crop shall not be grown on an active
sewage sludge unit, unless the owner/
operator of the surface disposal site
demonstrates to the permitting authority
that through management practices
public health and the environment are
protected from any reasonably
anticipated adverse effects of pollutants
in sewage sludge when crops are grown.
(1) Animals snail not be grazed on an
active sewage sludge unit, unless the
owner/operator of the surface disposal
site demonstrates to the permitting
authority that through management
practices public health and the
environment are protected from any
reasonably anticipated adverse effects of
pollutants in sewage sludge when
animals are grazed.
(m) Public access to a surface disposal
site shall be restricted for the period that
the surface disposal site contains an
active sewage sludge unit and for three
years after the last active sewage sludge
unit in the surface disposal site closes.
(n)(l) Sewage sludge placed on an
active sewage sludge unit shall not
contaminate an aquifer.
(2) Results of a ground-water
monitoring program developed by a
qualified ground-water scientist or a
certification by a qualified ground-water
scientist shall be used to demonstrate
that sewage sludge placed on an active
sewage sludge unit does not
contaminate an aquifer.
§503.25 Operational standards—
pathogens and vector attraction reduction.
(a) Pathogens—sewage sludge (other
than domestic septage). The Class A
pathogens requirements in § 503.32(a) or
one of the Class B pathogen
requirements in § 503.32 (b)(2) through
(b)(4) shall be met when sewage sludge
is placed on an active sewage sludge
unit, unless the vector attraction
reduction requirement in § 503.33(b)(ll)
is met.
(b) Vector attraction reduction—
sewage sludge (other than domestic
septage). One of the vector attraction
reduction requirements in § 503.33
(bXl) through (b)(ll) shall be met when
sewage sludge is placed on an active
sewage sludge unit.
(c) Vector attraction reduction—
domestic septage. One of the vector
attraction reduction requirement in
§ 503.33 (b)(9) through (b)(12) shall be
met when domestic septage is placed on
an active sewage sludge unit.
§ 503.26 Frequency of monitoring.
(a) Sewage sludge (other than
domestic septage).
(1) The frequency of monitoring for
the pollutants in Tables 1 and 2 of
§ 503.23; the pathogen density
requirements in § 503.32(a) and in
§ 503.32 (b)(2) through (b)(4); and the
vector attraction reduction requirements
in § 503.33 (b)(D through (b)(8) for
sewage sludge placed on an active
sewage sludge unit shall be the
frequency in Table 1 of § 503.26.
TABLE 1 OF §503.26.—FREQUENCY OF
MONITORING—SURFACE DISPOSAL
Amount of sewage
sludge1 (metric tons per
365 day period)
Greater than zero but
less than 290.
Equal to or greater than
290 but less than
1,500.
Equal to or greater than
1,500 but less than
15,000.
Equal to or greater than
15,000.
Frequency
Once per year.
Once per quarter (four
times per year).
Once per 60 days (six
times per year).
Once per month (12
times per year).
1 Amount of sewage sludge placed on an active
sewage sludge unit (dry weight basis).
(2) After the sewage sludge has been
monitored for two years at the frequency
in Table 1 of § 503.26, the permitting
authority may reduce the frequency of
monitoring for pollutant concentrations
and for the pathogen density
requirements in § 503.32 (a)(5)(ii) and
(a){5)(iii), but in no case shall the
frequency of monitoring be less than
once per year when sewage sludge is
placed on an active sewage sludge unit.
(b) Domestic septage. If the vector
attraction reduction requirements in
§ 503.33(b)(12) are met when domestic
septage is placed on an active sewage
sludge unit, each container of domestic
septage shall be monitored for
compliance with those requirements.
(c) Air. Air in structures within a
surface disposal site and at the property
line of the surface disposal site shall be
monitored continuously for methane gas
during the period that the surface
disposal site contains an active sewage
sludge unit on which the sewage sludge
is covered and for three years after a
sewage sludge unit closes when a final
cover is placed on the sewage sludge.
(Approved by the Office of Management and
Budget under control number 2040-0157)
§503.27 Recordkeeping.
(a) When sewage sludge (other than
domestic septage) is placed on an active
sewage sludge unit:
(1) The person who prepares the
sewage sludge shall develop the
following information and shall retain
the information for five years.
(i) The concentration of each
pollutant listed in Table 1 of § 503.23 in
the sewage sludge when the pollutant
concentrations in Table 1 of § 503.23 are
met.
(ii) The following certification
statement:
"I certify, under penalty of law, that the
pathogen requirements in [insert § 503.32(a),
§ 503.32(b)(2), § 503.32(b)(3), or § 503.32(b)(4)
when one of those requirements is met] and
the vector attraction reduction requirements
in [insert one of the vector attraction
-------
9398 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
reduction requirements in § 503.33(b)(l)
through §503.33(b)(8) when one of those
requirements Is met] have been met. This
determination has been made under my
direction and supervision In accordance with
(ho system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine the [pathogen
requirements and vector attraction reduction
requirements if appropriate] have been met.
1 am owaro that there are significant penalties
for falsa certification including the
possibility of fine and imprisonment."
(Hi) A description of how the
pathogen requirements in § 503.32 (a),
(b)(2), (b)(3), or (b)(4) are met when one
of those requirements is met.
(iv) A description of how one of the
vector attraction reduction requirements
in § 503.33 (b)(l) through (b)(8) is met
when one of those requirements is met.
(2) The owner/operator of the surface
disposal site, shall develop the
following information and shall retain
that information for five years.
(!) The concentration of each ,
pollutant listed in Table 2 of § 503.23 in
tho sowage sludge when the pollutant
concentrations in Table 2 of § 503.23 are
met or when site-specific pollutant
limits in §503.23(b) are met.
(ii) The following certification
statement:
"I certify, under penalty of law, that the
management practices in § 503.24 and the
vector attraction reduction requirement in
[Insert one of (ho requirements in § 503.33
(b)(9) through (b)(ll) if one of those
requirements Is met] have been met. This
determination has been made under my
direction and supervision in accordance with
Iho system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the
management practices [and the vector
attraction reduction requirements if
appropriate] have boon met. I am aware that
there nro significant penalties for false
certification including the possibility of fine
and Imprisonment."
(Hi) A description of how the
management practices in § 503.24 are
mot.
(iv) A description of how the vector
attraction reduction requirements in
§503.33 (b)(9) through (b)(ll) are met if
one of those requirements is met.
(b) When domestic septage is placed
on a surface disposal site:
(1) If the vector attraction reduction
requirements in § 503.33(b)(12) are met,
the person who places the domestic
soptngo on the surface disposal site shall
develop the following information and
shall retain the information for five
years:
(i) The following certification
statement:
"I certify, under penalty of law, that the
vector attraction reduction requirements in
§ 503.33(b)(12) have been met. This
determination has been made under my
direction and supervision in accordance with
the system designed to ensure that qualified
personnel properly gather and evaluate the
information used to determine that the vector
attraction requirements have been met. I am
aware that there are significant penalties for
false certification including the possibility of
fine and imprisonment."
(ii) A description of how the vector
attraction reduction requirements in
§ 503.33(b)(12) are met.
(2) The owner/operator of the surface
disposal site shall develop the following
information and shall retain that
information for five years:
(i) The following certification
statement:
"I certify, under penalty of law, that the
management practices in § 503.24 and the
vector attraction reduction requirements in
[insert § 503.33(b){9) through § 503.33(b)(ll)
when one of those requirements is met] have
been met. This determination has been made
under my direction and supervision in
accordance with the system designed to
ensure that qualified personnel properly
gather and evaluate the information used to
determine that the management practices
[and the vector attraction reduction
requirements if appropriate] have been met.
I am aware that there are significant penalties
for false certification including the
possibility of fine or imprisonment."
(ii) A description of how the
management practices in § 503.24 are
met.
(iii) A description how the vector
attraction reduction requirements in
§ 503.33(b)(9) through § 503.33(b)(ll)
are met if one of those requirements is
met.
(Approved by the Office of Management and
Budget under control number 2040-0157)
§503.28 Reporting.
Class I sludge management facilities,
POTWs (as defined in 40 CFR 501.2)
with a design flow rate equal to or
greater than one million gallons per day,
and POTWs that serve 10,000 people or
more shall submit the information in
§ 503.27(a) to the permitting authority
on February 19 of each year.
(Approved by the Office of Management and
Budget under control number 2040-0157)
Subpart D—Pathogens and Vector
Attraction Reduction
§503.30 Scope.
(a) This subpart contains the
requirements for a sewage sludge to be
classified either Class A or Class B with
respect to pathogens.
(b) This subpart contains the site
restrictions for land on which a Class B
sewage sludge is applied.
(c) This subpart contains the pathogen
requirements for domestic septage
applied to agricultural land, forest, or a
reclamation site.
(d) This subpart contains alternative
vector attraction reduction requirements
for sewage sludge that is applied to the
land or placed on a surface disposal site.
§503.31 Special definitions.
(a) Aerobic digestion is the
biochemical decomposition of organic
matter in sewage sludge into carbon
dioxide and water by microorganisms in
the presence of air.
(b) Anaerobic digestion is the
biochemical decomposition of organic
matter in sewage sludge into methane
gas and carbon dioxide by
microorganisms in the absence of air.
(c) Density of microorganisms is the
number of microorganisms per unit
mass of total solids (dry weight) in the
sewage sludge.
(d) Land with a high potential for
public exposure is land that the public
uses frequently. This includes, but is
not limited to, a public contact site and
a reclamation site located in a populated
area (e.g, a construction site located in
a city).
(e) Land with a low potential for
public exposure is land that the public
uses infrequently. This includes, but is
not limited to, agricultural land, forest,
and a reclamation site located in an
unpopulated area (e.g., a strip mine
located in a rural area).
(f) Pathogenic organisms are disease-
causing organisms. These include, but
are not limited to, certain bacteria,
protozoa, viruses, and viable helminth
ova.
(g) pH means the logarithm of the
reciprocal of the hydrogen ion
concentration.
(h) Specific oxygen uptake rate
(SOUR) is the mass of oxygen consumed
per unit time per unit mass of total
solids (dry weight basis) in the sewage
sludge.
(i) Total solids are the materials in
sewage sludge that remain as residue
when the sewage sludge is dried at 103
to 105 degrees Celsius.
(j) Unstabilized solids are organic
materials in sewage sludge that have not
been treated in either an aerobic or
anaerobic treatment process.
(k) Vector attraction is the
characteristic of sewage sludge that
attracts rodents, flies, mosquitos, or
other organisms capable of transporting
infectious agents.
(1) Volatile solids is the amount of the
total solids in sewage sludge lost when
the sewage sludge is combusted at 550
degrees Celsius in the presence of
excess air.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9399
§503.32 Pathogens.
(a) Sewage sludge—Class A. (1) The
requirement in § 503.32(a)(2) and the
requirements in either § 503.32(a)(3),
(a)(4), (a)(5), (a)(6), (a)(7), or (a)(8) shall
he met for a sewage sludge to be
classified Class A with respect to
pathogens.
(2) The Class A pathogen
requirements in § 503.32 (a)(3) through
(a)(8) shall be met either prior to
meeting or at the same time the vector
attraction reduction requirements in
§ 503.33, except the vector attraction
reduction requirements in § 503.33
(b)(6) through (b)(8), are met.
(3) Class A—Alternative 1. (i) Either
the density of fecal coliform in the
sewage sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella sp. bacteria in the sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
the time the sewage sludge is prepared
for sale or give away in a bag or other
container for application to the land; or
at the time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§ 593.10 (b), (c), (e), or (f).
(ii) The temperature of the sewage
sludge that is used or disposed shall be
maintained at a specific value for a
period of time.
(A) When the percent solids of the
sewage sludge is seven percent or
higher, the temperature of the sewage
sludge shall be 50 degrees Celsius or
higher; the time period shall be 20
minutes or longer; and the temperature
and time period shall be determined
using equation (2), except when small
particles of sewage sludge are heated by
either warmed gases or an immiscible
liquid.
D=
131,700,000
100.1400t
Eq. (2)
Where,
D=time in days.
t=temperature in degrees Celsius.
(B) When the percent solids of the
sewage sludge is seven percent or higher
and small particles of sewage sludge are
heated by either warmed gases or an
immiscible liquid, the temperature of
the sewage sludge shall be 50 degrees
Celsius or higher; the time period shall
be 15 seconds or longer; and the
temperature and time period shall be
determined using equation (2).
(C) When the percent solids of the
sewage sludge is less than seven percent
and the time period is at least 15
seconds, but less than 30 minutes, the
temperature and time period shall be
determined using equation (2).
(D) When the percent solids of the
sewage sludge is less than seven
percent; the temperature of the sewage
sludge is 50 degrees Celsius or higher;
and the time period is 30 minutes or
longer, the temperature and time period
shall be determined using equation (3).
50,070,000
D= Eq. (3)
•JQ0.1400I
Where,
D=time in days.
t=temperature in degrees Celsius.
(4) Class A—Alternative 2. (i) Either
the density of fecal coliform in the
sewage sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella sp. bacteria in the sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
the time the sewage sludge is prepared
for sale or give away in a bag or other
container for application to the land; or
at the time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§ 503.10 (b), (c), (e), or (f).
(ii) (A) The pH of the sewage sludge
that is used or disposed shall be raised
to above 12 and shall remain above 12
for 72 hours.
(B) The temperature of the sewage
sludge shall be above 52 degrees Celsius
for 12 hours or longer during the period
that the pH of the sewage sludge is
above 12.
(C) At the end of the 72 hour period
during which the pH of the sewage
sludge is above 12, the sewage sludge
shall be air dried to achieve a percent
solids in the sewage sludge greater than
50 percent.
(5) Class A—Alternative 3. (i) Either
the density of fecal coliform in the
sewage sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella sp. bacteria in sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
the time the sewage sludge is prepared
for sale or give away in a bag or other
container for application to the land; or
at the time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§ 503.10 (b), (c), (e), or (f).
(ii) (A) The sewage sludge shall be
analyzed prior to pathogen treatment to
determine whether the sewage sludge
contains enteric viruses.
(B) When the density of enteric
viruses in the sewage sludge prior to
pathogen treatment is less than one
Plaque-forming Unit per four grams of
total solids (dry weight basis), the
sewage sludge is Class A with respect to
enteric viruses until the next monitoring
episode for the sewage sludge.
(C) When the density of enteric
viruses in the sewage sludge prior to
pathogen treatment is equal to or greater
than one Plaque-forming Unit per four
grams of total solids (dry weight basis),
the sewage sludge is Class A with
respect to enteric viruses when the
density of enteric viruses in the sewage
sludge after pathogen treatment is less
than one Plaque-forming Unit per four
grams of total solids (dry weight basis)
and when the values or ranges of values
for the operating parameters for the
pathogen treatment process that
produces the sewage sludge that meets
the enteric virus density requirement
are documented.
(D) After the enteric virus reduction
in paragraph (a)(5)(ii)(C) of this section
is demonstrated for the pathogen
treatment process, the sewage sludge
continues to be Class A with respect to
enteric viruses when the values for the
pathogen treatment process operating
parameters are consistent with the
values or ranges of values documented
in paragraph (a)(5)(ii)(C) of this section.
(iii)(A) The sewage sludge shall be
analyzed prior to pathogen treatment to
determine whether the sewage sludge
contains viable helminth ova.
(B) When the density of viable
helminth ova in the sewage sludge prior
to pathogen treatment is less than one
per four grams of total solids (dry
weight basis), the sewage sludge is Class
A with respect to viable helminth ova
until the next monitoring episode for
the sewage sludge.
(C) When the density of viable
helminth ova in the sewage sludge prior
to pathogen treatment is equal to or
greater than one per four grams of total
solids (dry weight basis), the sewage
sludge is Class A with respect to viable
helminth ova when the density of viable
helminth ova in the sewage sludge after
pathogen treatment is less than one per
four grams of total solids (dry weight
basis) and when the values or ranges of
values for the operating parameters for
the pathogen treatment process that
produces the sewage sludge that meets
the viable helminth ova density
requirement are documented.
(D) After the viable helminth ova
reduction in paragraph (a)(5)(iii)(C) of
this section is demonstrated for the
pathogen treatment process, the sewage
-------
9400 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
sludge continues to be Class A with
respect to viable helminth ova when the
values for the pathogen treatment
process operating parameters are
consistent with the values or ranges of
values documented in paragraph
(a)(5)(iii)(C) of this section.
(6) Class A—Alternative 4. (i) Either
the density of fecal coliform in the
sowogo sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella sp. bacteria in the sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
the time the sewage sludge is prepared
for sale or give away in a bag or other
container for application to the land; or
at the time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§503.10 (fa), (c),(e), or (f).
(it) The density of enteric viruses in
the sewage sludge shall be less than one
Plaque-forming Unit per four grams of
total solids (dry weight basis) at the time
the sewage sludge is used or disposed;
at the time the sewage sludge is
prepared for sale or give away in a bag
or other container for application to the
land; or at the time the sewage sludge
or material derived from sewage sludge
is prepared to meet the requirements in
§503.10 (b), (c), (e), or (f), unless
otherwise specified by the permitting
authority.
(iii) The density of viable helminth
ova in the sewage sludge shall be less
than one per four grams of total solids
(dry weight basis) at the time the sewage
sludge is used or disposed; at the time
the sewage sludge is prepared for sale or
give away in a bag or other container for
application to the land; or at the time
the sewage sludge or material derived
from sewage sludge is prepared to meet
the requirements in § 503.10 (b), (c), (e),
or (f), unless otherwise specified by the
permitting authority.
(7) Class A—Alternative 5. (i) Either
the density of fecal coliform in the
sewage sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella, sp. bacteria in the sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
tho time the sewage sludge is prepared
for sale or given away in a bag or other
container for application to the land; or
at tho time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§503.10(b),(c),(e),or(f).
(ii) Sewage sludge that is used or
disposed shall be treated in one of the
Processes to Further Reduce Pathogens
described in appendix B of this part.
(8) Class A—Alternative 6. (i) Either
the density of fecal coliform in the
sewage sludge shall be less than 1000
Most Probable Number per gram of total
solids (dry weight basis), or the density
of Salmonella, sp. bacteria in the sewage
sludge shall be less than three Most
Probable Number per four grams of total
solids (dry weight basis) at the time the
sewage sludge is used or disposed; at
the time the sewage sludge is prepared
for sale or given away in a bag or other
container for application to the land; or
at the time the sewage sludge or
material derived from sewage sludge is
prepared to meet the requirements in
§593.10(b), (c),(e), or (f).
(ii) Sewage sludge that is used or
disposed shall be treated in a process
that is equivalent to a Process to Further
Reduce Pathogens, as determined by the
permitting authority.
(b) Sewage sludge—Class B. (l)(i) The
requirements in either § 503.32(b)(2),
(b)(3), or (b)(4) shall be met for a sewage
sludge to be classified Class B with
respect to pathogens.
(ii) The site restrictions in
§ 503.32(b)(5) shall be met when sewage
sludge that meets the Class B pathogen
requirements in § 503.32(b)(2), (b)(3), or
(b)(4) is applied to the land.
(2) Class B—Alternative 1.
(i) Seven samples of the sewage
sludge shall be collected at the time the
sewage sludge is used or disposed.
(ii) The geometric mean of the density
of fecal coliform in the samples
collected in paragraph (b)(2)(i) of this
section shall be less than either
2,000,000 Most Probable Number per
gram of total solids (dry weight basis) or
2,000,000 Colony Forming Units per
gram of total solids (dry weight basis).
(3) Class B—Alternative 2. Sewage
sludge that is used or disposed shall be
treated in one of the Processes to
Significantly Reduce Pathogens
described in appendix B of this part.
(4) Class B—Alternative 3. Sewage
sludge that is used or disposed shall be
treated in a process that is equivalent to
a Process to Significantly Reduce
Pathogens, as determined by the
permitting authority.
(5) Site Restrictions, (i) Food crops
with harvested parts that touch the
sewage sludge/soil mixture and are
totally above the land surface shall not
be harvested for 14 months after
application of sewage sludge.
(ii) Food crops with harvested parts
below the surface of the land shall not
be harvested for 20 months after
application of sewage sludge when the
sewage sludge remains on the land
surface for four months or longer prior
to incorporation into the soil.
(iii) Food crops with harvested parts
below the surface of the land shall not
be harvested for 38 months after
application of sewage sludge when the
sewage sludge remains on the land
surface for less than four months prior
to incorporation into the soil.
(iv) Food crops, feed crops, and fiber
crops shall not be harvested for 30 days
after application of sewage sludge.
(v) Animals shall not be allowed to
graze on the land for 30 days after
application of sewage sludge.
(vi) Turf grown on land where sewage
sludge is applied shall not be harvested
for one year after application of the
sewage sludge when the harvested turf
is placed on either land with a high
potential for public exposure or a lawn,
unless otherwise specified by the
permitting authority.
(vii) Public access to land with a high
potential for public exposure shall be
restricted for one year after application
of sewage sludge.
(viii) Public access to land with a low
potential for public exposure shall be
restricted for 30 days after application of
sewage sludge.
(c) Domestic septage. (1) The site
restrictions in § 503.32(b)(5) shall be
met when domestic septage is applied to
agricultural land, forest, or a
reclamation site; or
(2) The pH of domestic septage
applied to agricultural land, forest, or a
reclamation site shall be raised to 12 or
higher by alkali addition and, without
the addition of more alkali, shall remain
at 12 or higher for 30 minutes and the
site restrictions in § 503.32 (b)(5)(i)
through (b)(5)(iv) shall be met.
§ 503.33 Vector attraction reduction.
(a)(l) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(10) shall be met when
bulk sewage sludge is applied to
agricultural land, forest, a public contact
site, or a reclamation site.
(2) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(8) shall be met when
bulk sewage sludge is applied to a lawn
or a home garden.
(3) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(8) shall be met when
sewage sludge is sold or given away in
a bag or other container for application
to the land.
(4) One of the vector attraction
reduction requirements in § 503.33
(b)(l) through (b)(ll) shall be met when
sewage sludge (other than domestic
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9401
septage) is placed on an active sewage
sludge unit.
(5) One of the vector attraction
reduction requirements in § 503.33
(b)(9), (b)(10), or (b)(12) shall be met
when domestic septage is applied to
agricultural land, forest, or a
reclamation site and one of the vector
attraction reduction requirements in
§ 503.33 (b)(9) through (b)(12) shall be
met when domestic septage is placed on
an active sewage sludge unit.
(b)(l) The mass of volatile solids in
the sewage sludge shall be reduced by
a minimum of 38 percent (see
calculation procedures in
"Environmental Regulations and
Technology—Control of Pathogens and
Vector Attraction in Sewage Sludge",
EPA-625/R-92/013,1992, U.S.
Environmental Protection Agency,
Cincinnati, Ohio 45268).
(2) When the 38 percent volatile
solids reduction requirement in
§ 503.33(b)(l) cannot be met for an
anaerobically digested sewage sludge,
vector attraction reduction can be
demonstrated by digesting a portion of
the previously digested sewage sludge
anaerobically in the laboratory in a
bench-scale unit for 40 additional days
at a temperature between 30 and 37
degrees Celsius. When at the end of the
40 days, the volatile solids in the
sewage sludge at the beginning of that
period is reduced by less than 17
percent, vector attraction reduction is
achieved.
(3) When the 38 percent volatile
solids reduction requirement in
§ 503.33(b)(l) cannot be met for an
aerobically digested sewage sludge,
vector attraction reduction can be
demonstrated by digesting a portion of
the previously digested sewage sludge
that has a percent solids of two percent
or less aerobically in the laboratory in
a bench-scale unit for 30 additional days
at 20 degrees Celsius. When at the end
of the 30 days, the volatile solids in the
sewage sludge at the beginning of that
period is reduced by less than 15
percent, vector attraction reduction is
achieved.
(4) The specific oxygen uptake rate
(SOUR) for sewage sludge treated in an
aerobic process shall be equal to or less
than 1.5 milligrams of oxygen per hour
per gram of total solids (dry weight
basis) at a temperature of 20 degrees
Celsius.
(5) Sewage sludge shall be treated in
an aerobic process for 14 days or longer.
During that time, the temperature of the
sewage sludge shall be higher than 40
degrees Celsius and the average
temperature of the sewage sludge shall
be higher than 45 degrees Celsius.
(6) The pH of sewage sludge shall be
raised to 12 or higher by alkali addition
and, without the addition of more alkali,
shall remain at 12 or higher for two
hours and then at 11.5 or higher for an
additional 22 hours.
(7) The percent solids of sewage
sludge that does not contain
unstabilized solids generated in a
primary wastewater treatment process
shall be equal to or greater than 75
percent based on the moisture content
and total solids prior to mixing with
other materials.
(8) The percent solids of sewage
sludge that contains unstabilized solids
generated in a primary wastewater
treatment process shall be equal to or
greater than 90 percent based on the
moisture content and total solids prior
to mixing with other materials.
(9)(i) Sewage sludge shall be injected
below the surface of the land.
(ii) No significant amount of the
sewage sludge shall be present on the
land surface within one hour after the
sewage sludge is injected.
(iii) When the sewage sludge that is
injected below the surface of the land is
Class A with respect to pathogens, the
sewage sludge shall be injected below
the land surface within eight hours after
being discharged from the pathogen
treatment process.
(10) (i) Sewage sludge applied to the
land surface or placed on a surface
disposal site shall be incorporated into
the soil within six hours after
application to or placement on the land.
(ii) When sewage sludge that is
incorporated into the soil is Class A
with respect to pathogens, the sewage
sludge shall be applied to or placed on
the land within eight hours after being
discharged from the pathogen treatment
process.
(11) Sewage sludge placed on an
active sewage sludge unit shall be
covered with soil or other material at
the end of each operating day.
(12) The pH of domestic septage shall
be raised to 12 or higher by alkali
addition and, without the addition of
more alkali, shall remain at 12 or higher
for 30 minutes.
Subpart E—Incineration
§503.40 Applicability.
(a) This subpart applies to a person
who fires sewage sludge in a sewage
sludge incinerator, to a sewage sludge
incinerator, and to sewage sludge fired
in a sewage sludge incinerator.
(b) This subpart applies to the exit gas
from a sewage sludge incinerator stack.
§503.41 Special definitions.
(a) Air pollution control device is one
or more processes used to treat the exit
gas from a sewage sludge incinerator
stack.
(b) Auxiliary fuel is fuel used to
augment the fuel value of sewage
sludge. This includes, but is not limited
to, natural gas, fuel oil, coal, gas
generated during anaerobic digestion of
sewage sludge, and municipal solid
waste (not to exceed 30 percent of the
dry weight of sewage sludge and
auxiliary fuel together). Hazardous
wastes are not auxiliary fuel.
(c) Control efficiency is the mass of a
pollutant in the sewage sludge fed to an
incinerator minus the mass of that
pollutant in the exit gas from the
incinerator stack divided by the mass of
the pollutant in the sewage sludge fed
to the incinerator.
(d) Dispersion factor is the ratio of the
increase in the ground level ambient air
concentration for a pollutant at or
beyond the property line of the site
where the sewage sludge incinerator is
located to the mass emission rate for the
pollutant from the incinerator stack.
(e) Fluidized bed incinerator is an
enclosed device in which organic matter
and inorganic matter in sewage sludge
are combusted in a bed of particles
suspended in the combustion chamber
gas.
(f) Hourly average is the arithmetic
mean of all measurements, taken during
an hour. At least two measurements
must be taken during the hour.
(g) Incineration is the combustion of
organic matter and inorganic matter in
sewage sludge by high temperatures in
an enclosed device.
(h) Monthly average is the arithmetic
mean of the hourly averages for the
hours a sewage sludge incinerator
operates during the month.
(i) Risk specific concentration is the
allowable increase in the average daily
ground level ambient air concentration
for a pollutant from the incineration of
sewage sludge at or beyond the property
line of the site where the sewage sludge
incinerator is located.
(j) Sewage sludge feed rate is either
the average daily amount of sewage
sludge fired in all sewage sludge
incinerators within the property line of
the site where the sewage sludge
incinerators are located for the number
of days in a 365 day period that each
sewage sludge incinerator operates, or
the average daily design capacity for all
sewage sludge incinerators within the
property line of the site where the
sewage sludge incinerators are located.
(k) Sewage sludge incinerator is an
enclosed device in which only sewage
sludge and auxiliary fuel are fired.
(1) Stack height is the difference
between the elevation of the top of a
sewage sludge incinerator stack and the
-------
9402 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
elevation of the ground at the base of the
stack whon the difference is equal to or
loss than 65 meters. When the difference
is greater than 65 meters, stack height is
the creditable stack height determined
in accordance with 40 CFR 51.100 (ii).
(m) Total hydrocarbons means the
organic compounds in the exit gas from
a sewage sludge incinerator stack
measured using a flame ionization
detection instrument referenced to
propane.
(n) Wet electrostatic precipitator is an
air pollution control device that uses
both electrical forces and water to
remove pollutants in the exit gas from
a sewage sludge incinerator stack.
(o) Wet scrubber is an air pollution
control device that uses water to remove
pollutants in the exit gas from a sewage
sludge incinerator stack.
§503.42 General requirements.
No person shall fire sewage sludge in
a sewage sludge incinerator except in
compliance with the requirements in
this subpart.
§503.43 Pollutant limits.
(a) Firing of sewage sludge in a
sewage sludge incinerator shall not
violate the requirements in the National
Emission Standard for Beryllium in
subpart C of 40 CFR part 61.
(o) Firing of sewage sludge in a
sewage sludge incinerator shall not
violate the requirements in the National
Emission Standard for Mercury in
subpart E of 40 CFR part 61.
(cj Pollutant limit—lead.
(1) The daily concentration of lead in
sewage sludge fed to a sewage sludge
incinerator shall not exceed the
concentration calculated using Equation
(4).
0.1xNAAQSx86.400
DFx(l-CE)xSF
Eq. (4)
Whoro:
C=Dally concentration of lead in sewage
sludgo in milligrams per kilogram of
total solids (dry weight basis).
NAAQS»National Ambient Air Quality
Standard for lead in micrograms per
cubic motor.
DF«Dlspcrsion factor in micrograms per
cubic motor per gram per second.
CE»Sowogo sludgo incinerator control
efficiency for load in hundredths.
SF»Sowago sludgo food rate in metric tons
per day (dry weight basis).
(2)(i) When the sewage sludge stack
height is 65 meters or less, the actual
sewage sludge incinerator stack height
shall bo used in an air dispersion model
specified by the permitting authority to
determine the dispersion factor (DF) in
equation (4).
(ii) When the sewage sludge
incinerator stack height exceeds 65
meters, the creditable stack height shall
be determined in accordance with 40
CFR 51.100(ii) and the creditable stack
height shall be used in an air dispersion
model specified by the permitting
authority to determine the dispersion
factor (DF) in equation (4).
(3) The control efficiency (CE) in
equation (5) shall be determined from a
performance test of the sewage sludge
incinerator, as specified by the
permitting authority.
(d) Pollutant limit—arsenic,
cadmium, chromium, and nickel.
(1) The daily concentration for
arsenic, cadmium, chromium, and
nickel in sewage sludge fed to a sewage
sludge incinerator each shall not exceed
the concentration calculated using
equation (5).
TABLE 2 OF § 503.43.—RISK SPECIFIC
, CONCENTRATION—CHROMIUM
C=
RSCx86,400
DFx(l-CE)xSF
Eq. (5)
Where:
C=Daily concentration of arsenic,
cadmium, chromium, or nickel in
sewage sludge in milligrams per
kilogram of total solids (dry weight
basis).
CE=Sewage sludge incinerator control
efficiency for arsenic, cadmium,
chromium, or nickel in hundredths.
DF=Dispersion factor in micrograms per
cubic meter per gram per second.
RSC=Risk specific concentration in
micrograms per cubic meter. S
F=Sewage sludge feed rate in met.ric tons
per day (dry weight basis).
(2) The risk specific concentrations
for arsenic, cadmium, and nickel used
in equation (6) shall be obtained from
Table 1 of §503 .43.
TABLE 1 OF § 503.43.—RISK SPECIFIC
CONCENTRATION ARSENIC, CADMIUM,
AND NICKEL
Pollutant
Arsenic
Cadmium
Nickel
Risk specific
concentration
(micrograms per
cubic meter)
0.023
0.057
20
(3) The risk specific concentration for
chromium used in equation (5) shall be
obtained from Table 2 of § 503.43 or
shall be calculated using equation (6), as
specified by the permitting authority.
Type of Incinerator
Fluldized bed with wet scrubber .
Fluldlzed bed with wet scrubber
and wet electrostatic precipi-
tator
Other types with wet scrubber ....
Other types with wet scrubber
and wet electrostatic precipi-
tator
Risk specific con-
centration
(micrograms per
cubic meter)
0.65
023
0.064
0.016
RSC=
0.0085
Eq. (6)
Where:
RSC=risk specific concentration for
chromium in micrograms per cubic
meter used in equation (5).
r=decimal fraction of the hexavalent
chromium concentration in the total
chromium concentration measured in
the exit gas from the sewage sludge
incinerator stack in hundredths.
(4)(i) When the sewage sludge
incinerator stack height is equal to or
less than 65 meters, the actual sewage
sludge incinerator stack height shall be
used in an air dispersion model, as
specified by the permitting authority, to
determine the dispersion factor (DF) in
equation (5).
(ii) When the sewage sludge
incinerator stack height is greater than
65 meters, the creditable stack height
shall be determined in accordance with
40 CFR Sl.lOO(ii) and the creditable
stack height shall be used in an air
dispersion model, as specified by the
permitting authority, to determine the
dispersion factor (DF) in equation (5).
(5) The control efficiency (CE) in
equation (5) shall be determined from a
performance test of the sewage sludge
incinerator, as specified by the
permitting authority.
§ 503.44 Operational standard—total
hydrocarbons.
(a) The total hydrocarbons
concentration in the exit gas from a
sewage sludge incinerator shall be
corrected for zero percent moisture by
multiplying the measured total
hydrocarbons concentration by the
correction factor calculated using
equation (7).
Correction factor (per-
cent moisture)=
(1-X)
Eq. (7)
Where:
X=decimal fraction of the percent moisture
in the sewage sludge incinerator exit gas
in hundredths.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9403
(b) The total hydrocarbons
concentration in the exit gas from a
sewage sludge incinerator shall be
corrected to seven percent oxygen by
multiplying the measured total
hydrocarbons concentration by the
correction factor calculated using
equation (8).
Correction factor (ox-
ygen)=
14
(21—Y)
Eq. (8)
Where:
Y=Percent oxygen concentration in the
sewage sludge incinerator stack exit gas
(dry volume/dry volume).
(c) The monthly average
concentration for total hydrocarbons in
the exit gas from a sewage sludge
incinerator stack, corrected for zero
percent moisture using the correction
factor from equation (7) and to seven
percent oxygen using the correction
factor from equation (8), shall not
exceed 100 parts per million on a
volumetric basis when measured using
the instrument required by § 503.45(a).
§ 503.45 Management practices.
(a)(l) An instrument that measures
and records the total hydrocarbons
concentration in the sewage sludge
incinerator stack exit gas continuously
shall be installed, calibrated, operated,
and maintained for each sewage sludge
incinerator, as specified by the
permitting authority.
(2) The total hydrocarbons instrument
shall employ a flame ionization
detector; shall have a heated sampling
line maintained at a temperature of 150
degrees Celsius or higher at all times;
and shall be calibrated at least once
every 24-hour operating period using
propane.
(b) An instrument that measures and
records the oxygen concentration in the
sewage sludge incinerator stack exit gas
continuously shall be installed,
calibrated, operated, and maintained for
each sewage sludge incinerator, as
specified by the permitting authority.
(c) An instrument that measures and
records information used to determine
the moisture content in the sewage
sludge incinerator stack exit gas
continuously shall be installed,
calibrated, operated, and maintained for
each sewage sludge incinerator, as
specified by the permitting authority.
(d) An instrument that measures and
records combustion temperatures
continuously shall be installed,
calibrated, operated, and maintained for
each sewage sludge incinerator, as
specified by the permitting authority.
(e) The maximum combustion
temperature for a sewage sludge
incinerator shall be specified by the
permitting authority and shall be based
on information obtained during the
performance test of the sewage sludge
incinerator to determine pollutant
control efficiencies.
(f) The values for the operating
parameters for the sewage sludge
incinerator air pollution control device
shall be specified by the permitting
authority and shall be based on
information obtained during the
performance test of the sewage sludge
incinerator to determine pollutant
control efficiencies.
(g) Sewage sludge shall not be fired in
a sewage sludge incinerator if it is likely
to adversely affect a threatened or
endangered species listed under section
4 of the Endangered Species Act or its
designated critical habitat.
§503.46 Frequency of monitoring.
(a) Sewage sludge.
(1) The frequency of monitoring for
beryllium and mercury shall be
specified by the permitting authority.
(2) The frequency of monitoring for
arsenic, cadmium, chromium, lead, and
nickel in sewage sludge fed to a sewage
sludge incinerator shall be the
frequency in Table 1 of § 503.46.
TABLE 1 OF §503.46.—FREQUENCY OF
MONITORING—INCINERATION
Amount of sewage sludge1 (metric
tons per 365 day period)
Greater than zero but less than
290.
Equal to or greater than 290 but
less than 1,500.
Equal to or greater than 1,500 but
less than 15,000.
Equal to or greater than 15,000
Frequency
Once per year.
Once per quar-
ter (lour
times per
year).
Once per 60
days (six
times per
year).
Once per
month (12
times per
year).
1 Amount of sewage sludge fired in a sewage
sludge incinerator (dry weight basis).
(3) After the sewage sludge has been
monitored for two years at the frequency
in Table 1 of § 503.46, the permitting
authority may reduce the frequency of
monitoring for arsenic, cadmium,
chromium, lead, and nickel, but in no
case shall the frequency of monitoring
be less than once per year when sewage
sludge is fired in a sewage sludge
incinerator.
(b) Total hydrocarbons, oxygen
concentration, information to determine
moisture content, and combustion
temperatures.
The total hydrocarbons concentration
and oxygen concentration in the exit gas
from a sewage sludge incinerator stack,
the information used to measure
moisture content in the exit gas, and the
combustion temperatures for the sewage
sludge incinerator shall be monitored
continuously.
(c) Air pollution control device
operating parameters.
The frequency of monitoring for the
sewage sludge incinerator air pollution
control device operating parameters
shall be specified by the permitting
authority.
(Approved by the Office of Management and
Budget under control number 2040-0157)
§503.47 Recordkeeping.
(a) The person who fires sewage
sludge in a sewage sludge incinerator
shall develop the information in
§ 503.47(b) through § 503.47(n) and
shall retain that information for five
years.
(b) The concentration of lead, arsenic,
cadmium, chromium, and nickel in the
sewage sludge fed to the sewage sludge
incinerator.
(c) The total hydrocarbons
concentrations in the exit gas from the
sewage sludge incinerator stack.
(d) Information that indicates the
requirements in the National Emission
Standard for beryllium in subpart C of
40 CFR part 61 are met.
(e) Information that indicates the
requirements in the National Emission
Standard for mercury in subpart E of 40
CFR part 61 are met.
(f) The combustion temperatures,
including the maximum combustion
temperature, for the sewage sludge
incinerator.
(g) Values for the air pollution control
device operating parameters.
(h) The oxygen concentration and
information used to measure moisture
content in the exit gas from the sewage
sludge incinerator stack.
(i) The sewage sludge feed rate.
(j) The stack height for the sewage
sludge incinerator.
(k) The dispersion factor for the site
where the sewage sludge incinerator is
located.
(1) The control efficiency for lead,
arsenic, cadmium, chromium, and
nickel for each sewage sludge
incinerator.
(m) The risk specific concentration for
chromium calculated using equation (6),
if applicable.
(n) A calibration and maintenance log
for the instruments used to measure the
total hydrocarbons concentration and
oxygen concentration in the exit gas
from the sewage sludge incinerator
stack, the information needed to
determine moisture content in the exit
gas, and the combustion temperatures.
-------
9404 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
(Approved by tho Offico of Management and
Budget under control number 2040-0157)
§503.43 Reporting.
Class I sludge management facilities,
POTWs (as defined in 40 CFR 501.2)
with a design flow rate equal to or
greater than one million gallons per day,
and POTWs that serve a population of
10,000 people or greater shall submit
the information in § 503.47(b) through
§503.47(h) to the permitting authority
on February 19 of each year.
(Approved by tho Office of Management and
Budget under control number 2040-0157)
Appendix A to Part 503—Procedure to
Determine the Annual Whole Sludge
Application Rate for a Sewage Sludge
Section 503.13(a)(4)(ii) requires that the
product of tho concentration for each
pollutant listod in Table 4 of § 503.13 in
sewngo sludge sold or given away in a bag
or oilier container for application to the land
and tho annual whole sludge application rate
(AWSAR) for the sewage sludge not cause the
annual pollutant loading rate for the
pollutant in Table 4 of § 503.13 to be
exceeded. This appendix contains the
procedure used to determine the AWSAR for
a scwago sludge that does not cause the
annual pollutant loading rates in Table 4 of
S 503.13 to bo exceeded.
Tho relationship between the annual
pollutant loading rate (APLR) for a pollutant
and tho annual whole sludge application rate
(AWSAR) for la sewage sludge is shown in
equation (1).
APLR*CxAWSARx0.001 (1)
Where:
APLR"Annual pollutant loading rate in
kilograms per hectare per 365 day
period.
OPollutant concentration in milligrams,
per kilogram of total solids (dry weight
basis).
AWSAR=Annual whole sludge application
rate in metric tons per hectare per 365
day period (dry weight basis).
O.OOlaA conversion factor.
To determine tho AWSAR, equation (1) is
rearranged Into equation (2):
AWSAR*
APLR
CxO.OOl
(2)
The procedure used to determine the
AWSAR for a sewage sludge is presented
below.
Procedure:
1. Analyze a sample of the sewage sludge
to determine tho concentration for each of the
pollutants listod in Table 4 of § 503.13 in the
sewage sludge.
2. Using the pollutant concentrations from
Stop 1 and tho APLRs from Table 4 of
§503.13, calculate an AWSAR for each
pollutant using equation (2) above.
3. The AWSAR for the sewage sludge is the
lowest AWSAR calculated in Step 2.
Appendix B to Part 503—Pathogen
Treatment Processes
A. Processes to Significantly Reduce
Pathogens (PSRP)
1. Aerobic digestion—Sewage sludge is
agitated with air or oxygen to maintain
aerobic conditions for a specific mean cell
residence time at a specific temperature.
Values for the mean cell residence time and
temperature shall be between 40 days at 20
degrees Celsius and 60 days at 15 degrees
Celsius.
2. Air drying—Sewage sludge is dried on
sand beds or on paved or unpaved basins.
The sewage sludge dries for a minimum of
three months. During two of the three
months, the ambient average daily
temperature is above zero degrees Celsius.
3. Anaerobic digestion—Sewage sludge is
treated in the absence of air for a specific
mean cell residence time at a specific
temperature. Values for the mean cell
residence time and temperature shall be
between 15 days at 35 to 55 degrees Celsius
and 60 days at 20 degrees Celsius.
4. Composting—Using either the within-
vessel, static aerated pile, or windrow
composting methods, the temperature of the
sewage sludge is raised to 40 degrees Celsius
or higher and remains at 40 degrees Celsius
or higher for five days. For four hours during
the five days, the temperature in the compost
pile exceeds 55 degrees Celsius.
5. Lime stabilization—Sufficient lime is
added to the sewage sludge to raise the pH
of the sewage sludge to 12 after two hours of
contact.
B. Processes to Further Reduce Pathogens
(PFRP)
1. Composting—Using either the within-
vessel composting method or the static
aerated pile composting method, the
temperature of the sewage sludge is
maintained at 55 degrees Celsius or higher
for three days.
Using the windrow composting method,
the temperature of the sewage sludge is
maintained at 55 degrees or higher for 15
days or longer. During the period when the
compost is maintained at 55 degrees or
higher, there shall be a minimum of five
turnings of the windrow.
2. Heat drying—Sewage sludge is dried by
direct or indirect contact with hot gases to
reduce the moisture content of the sewage
sludge to 10 percent or lower. Either the
temperature of the sewage sludge particles
exceeds 80 degrees Celsius or the wet bulb
temperature of the gas in contact with the
sewage sludge as the sewage sludge leaves
the dryer exceeds 80 degrees Celsius.
3. Heat treatment—Liquid sewage sludge is
heated to a temperature of 180 degrees
Celsius or higher for 30 minutes.
4. Thermophilic aerobic digestion—Liquid
sewage sludge is agitated with air or oxygen
to maintain aerobic conditions and the mean
cell residence time of the sewage sludge is 10
days at 55 to 60 degrees Celsius.
5. Beta ray irradiation—Sewage sludge is
irradiated with beta rays from an accelerator
at dosages of at least 1.0 megarad at room
temperature (ca. 20 degrees Celsius).
6. Gamma ray irradiation—Sewage sludge
is irradiated with gamma rays from certain
isotopes, such as Cobalt 60 and Cesium 137,
at room temperature (ca. 20 degrees Celsius).
7. Pasteurization—The temperature of the
sewage sludge is maintained at 70 degrees
Celsius or higher for 30 minutes or longer.
[FR Doc. 93-2 Filed 2-18-93; 8:45 am]
BILLING CODE 6560-01-M
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 122,123, and 501
[FRL-4515-7]
National Pollutant Discharge
Elimination System Sewage Sludge
Permit Regulations; State Sludge
Management Program Requirements
AGENCY: Environmental Protection
Agency.
ACTION: Final rule; technical
amendment.
SUMMARY: Under existing regulations
that establish sewage sludge permitting
and State sewage sludge program
requirements, approximately 20,000
publicly owned treatment works and
other treatment works treating domestic
sewage are required to submit permit
applications within 120 days after the
promulgation of standards applicable to
their sewage sludge use or disposal
practice(s). The h'nal sewage sludge use
and disposal standards will be
published in the Federal Register on or
near the same date as this final rule. To
facilitate the management of these
applications, on May 27,1992, EPA
proposed to revise these rules to stagger
the submission of permit applications.
Additionally, EPA proposed to extend
the time period during which the initial
set of applications must be submitted
from 120 days to 180 days after
promulgation of the technical standards.
In response to comments received on
the May 27,1992, proposal, EPA is
issuing a final rule which requires
permit applications in phases and
extends the time period in which the
initial applications are due following
the publication of the final use or
disposal standards.
On July 28,1986, EPA promulgated
final regulations for application
requirements for facilities that discharge
only non-process wastewater, which
resulted in internal recodificatioh of
§ 122.21. Conforming changes were not
made to § 123.25(a)(4) which refers to
the relevant portions of section 122.
These technical corrections are being
made as part of this rule.
EFFECTIVE DATE: The effective date of
this final rule is March 22,1993.
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9405
ADDRESSES: The public record is located
at EPA Headquarters, Environmental
Protection Agency, room 220 NE., 401
M Street SW., Washington, DC 20460.
For access to the record, call (202) 260-
6599 between 9 a.m. and 3:30 p.m. for
an appointment.
FOR FURTHER INFORMATION CONTACT:
Pamela Mazakas, Permits Division (EN—
336), Environmental Protection Agency,
401 M Street SW., Washington, DC
20460, (202) 260-6599.
SUPPLEMENTARY INFORMATION:
I. Background
A. Water Quality Act of 1987
B. EPA's Sewage Sludge Management
Program
C. Discussion of May 27,1992, Proposed
Rule
II. Discussion of Today's Final Rule and
Response to Comments
A. General
B. Applicability
C. Permit Application Deadlines
D. Time Period for Compiling Application
Data
E. Compliance with the CWA and Part 503
F. State Programs and the Permitting
Authority
G. Technical Correction to Section 123.25
III. Regulatory Development Process
A. Executive Order 12291
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
Appendix A—List of Regional Sewage
Sludge Contacts
I. Background
Implementation of the Clean Water
Act (CWA) has increased the extent to
which wastewater is treated before
being discharged to surface waters. At
publicly owned treatment works
(POTWs), implementation of secondary
treatment requirements under the
National Pollutant Discharge
Elimination System (NPDES) program,
under section 402 of the CWA, has
improved effluent quality while
increasing the amount of sewage sludge
being generated. Proper management of
this growing amount of sewage sludge is
becoming increasingly important as
efforts to remove pollutants from
wastewater have become more effective.
Several options exist for dealing with
these vast quantities of sewage sludge.
One such option is beneficial use. The
Agency considers sewage sludge a
valuable resource since it contains
nutrients and has physical properties
that make it useful as a fertilizer and
soil conditioner. Sewage sludge has
been used for its beneficial qualities on
agricultural lands, in forests, for
landscaping projects, and to reclaim
strip-mined land. EPA will continue to
encourage such practices.
Regulation of the use or disposal of
sewage sludge is important, however,
because improper use or disposal can
adversely, affect surface water, ground
water, wetlands, and public health
through a variety of exposure pathways.
The multi-media nature of the risks and
exposure pathways requires a tightly
coordinated comprehensive approach
that protects public health and the
environment, helps ensure that solving
problems in one medium will not create
problems for another, and encourages
the beneficial use of sewage sludge.
A. Water Quality Act of 1987
Section 406 of the Water Quality Act
of 1987, which amended section 405 of
the CWA, established a comprehensive
program for reducing the risks to public
health and the environment from the
use or disposal of sewage sludge. The
1987 revisions to the CWA reiterated
EPA's obligation to promulgate
standards for sewage sludge that protect
public health and the environment from
reasonably anticipated adverse effects of
pollutants in sewage sludge during its
use or disposal. Furthermore, the 1987
amendments required that all NPDES
permits issued to POTWs and other
treatment works treating domestic
sewage contain conditions
implementing sewage sludge standards,
unless such conditions are included in
a permit issued under subtitle C of the
Solid Waste Disposal Act, part C of the
Safe Drinking Water Act, the Marine
Protection, Research and Sanctuaries
Act, the Clean Air Act, or under a State
program approved for administering a
section 405(f) sewage sludge permitting
program. The amendments also
provided that the Administrator may
issue separate permits that implement
the sewage sludge requirements to
treatment works treating domestic
sewage that are not subject to section
402 of the CWA or to any of the other
listed permit programs or approved
State programs. Moreover, the
amendments provided that the
standards for use or disposal are
enforceable directly against any user or
disposer of sewage sludge under section
405(e) of the CWA. In other words, a
treatment works treating domestic
sewage, as well as any user or disposer,
must comply with the standards by the
statutory compliance deadlines whether
or not a permit incorporating the
standards has been issued to the
treatment works treating domestic
sewage.
B. EPA's Sewage Sludge Management
Program
In response to the February 1987
amendments to the CWA, EPA: (1)
Reproposed regulations for State sludge
management programs (first proposed
on February 4,1986 (51 FR 4458)); and
(2) proposed revisions to the NPDES
program regulations to provide for
including sewage sludge requirements
in NPDES permits. This was done on
March 9,1988 (53 FR 7642). Final rules
were promulgated on May 2,1989 (54
FR 18716). These regulations establish
permit requirements and procedures, as
well as requirements for States wishing
to implement approved sewage sludge
management programs as either part of
their NPDES programs or under separate
authority. These regulations establish
the programmatic framework for
implementing the technical standards
for sewage sludge use or disposal.
Central to the sewage sludge
permitting program is the development
of standards that protect public health
and the environment from reasonably
anticipated adverse effects of pollutants
in sewage sludge that is used or
disposed. On February 6,1989 (54 FR
5746), EPA proposed standards for the
use or disposal of sewage sludge if the
sewage sludge is applied to the land,
distributed and marketed, placed in
sludge-only landfills (monofills) or
surface disposal sites, or fired in a
sewage sludge incinerator. These
standards will be codified at 40 CFR
part 503 and will be published in the
Federal Register on or near the same
date as today's final rule. Among other
things, part 503 will likely replace the
current part 257 for the disposal of
sewage sludge if the sewage sludge is
used or disposed in accordance with
part 503.
On November 9,1990 (55 FR 47210),
EPA published a notice regarding the
availability of information and data
collected during the National Sewage
Sludge Survey and the anticipated
impacts of this information on the
proposed part 503 standards. At that
time, EPA proposed a number of
changes to the part 503, regulation as a
result of the survey and as a
consequence of information and
comments provided by scientific peer
review panels and public comments on
the proposed part 503 rule. As noted
above, the final part 503 regulation will
be published in the Federal Register on
or near the same date as today's final
rule.
C. Discussion of May 27, 1992, Proposed
Rule
Under the current regulations,
publicly owned treatment works
(POTWs) and other treatment works
treating domestic sewage are required to
submit permit applications within 120
days after the promulgation of standards
(40 CFR part 503) applicable to their
sewage sludge use or disposal
-------
9406 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
praclice(s). EPA estimates that up to
20,000 permit applications may be
submitted to EPA at one time as a result
of the current requirements. To facilitate
tho management of these applications,
on May 27,1992, EPA proposed to
revise tho existing rules to stagger the
submission of permit applications. In
the first phase, EPA proposed to require
permit applications from treatment
works treating domestic sewage
required to have (or requesting) site-
specific limits in the initial period
following promulgation of part 503.
(These are primarily sewage sludge
incinerators.) The second phase would
require limited background information
from sludge-only treatment works
treating domestic sewage (that were not
addressed in the first phase). The last
phase would require treatment works
treating domestic sewage with NPDES
permits (that were not addressed in the
first phase) to submit sewage sludge
information during the NPDES permit
renewal process (i.e., over the five year
permit cycle). Additionally, EPA
proposed to extend the time period
during which the initial ("first phase")
set of applications must be submitted
from 120 days to 180 days after
promulgation of part 503.
//. Discussion of Today's Final Bule and
Response to Comments
A. General
In developing the final rule, EPA
carefully considered public comments
received on the May 27,1992, proposal.
In total, EPA received comments from
12 commonters. The majority of
comments were from POTWs and
municipalities. EPA also received
comments from one State agency, one
industry, and one environmental group.
EPA's response to comments will be
included as part of the preamble to this
final rule.
The proposed rule noted that
applications were due within a certain
period of time after the "promulgation"
of applicable sewage sludge use or
disposal standards. Since promulgation,
for regulatory purposes, is generally
synonymous with the date the rule is
published in the Federal Register, EPA
is clarifying the final regulations by
stating that permit applications are due
after tho "publication" of applicable
sewage sludge use or disposal
standards. This clarification is also
consistent with the CWA requirement
that compliance with part 503 be within
ono year (or two years if construction is
required) after "publication" of an
applicable sewage sludge use or
disposal standard.
B. Applicability
One commenter was uncertain about
who would be affected by today's rule.
Under the Federal program, all
treatment works treating domestic
sewage must apply for a permit. The
May 27,1992, proposal did not address
who had to apply for a permit because
this was not being^changed. The
proposal merely addressed the timing
for submittal of permit applications. The
final regulations addressing sewage
sludge, which were promulgated in May
1989, addressed the scope of the
permitting program in detail (54 FR
18725-18732). That discussion is
summarized briefly below.
All treatment works treating domestic
sewage must apply for a permit. A
treatment works treating domestic
sewage is defined in §§ 122.2 and 501.2
as "a POTW or any other sewage sludge
or waste water treatment devices or
systems, regardless of ownership
(including federal facilities), used in the
storage, treatment, recycling, and
reclamation of municipal or domestic
sewage, including land dedicated for the
disposal of sewage sludge. This
definition does not include septic tanks
or similar devices." For purposes of this
definition, domestic sewage means
"waste and waste water from humans or
household operations that are
discharged to or otherwise enter a
treatment works."
In summary, as explained in the
preamble to the May 2,1989,
regulations, the definition of treatment
works treating domestic sewage
includes facilities that generate sewage
sludge or otherwise effectively control
the quality of sewage sludge or the
manner in which it is disposed. (Note
that land application is not considered
disposal since the sewage sludge is
being beneficially reused.) Under this
definition, "treatment works treating
domestic sewage" consequently
encompasses facilities that may process
sewage sludge as would a generator, but
that are separate from the generator's
facilities. Thus, commercial sewage
sludge handlers (like commercial
composting operations) that process
sewage sludge from POTWs for sale or
give-away are included in the definition
since they alter the quality of sewage
sludge. However, commercial handlers
that only distribute or land apply the
sewage sludge without changing the
quality are not automatically considered
treatment works treating domestic
sewage and are not required to submit
permit applications unless specifically
requested to do so by the permitting
authority (54 FR 18726). (The permitting
authority will be the EPA Regional
Office or a State with an approved
sewage sludge program.)
Also included in this definition is any
treatment works which treats, in whole
or in part, human-generated or
household type wastes (domestic wastes
or domestic sewage) as part of its
wastewater treatment. This includes
industrial treatment works that treat
site-generated domestic wastes along
with process or other wastes generated
at the site. It does not, however, apply
to sludges which are hazardous wastes,
that are covered under subtitle C of
RCRA. While industrial treatment works
treating site-generated domestic wastes
can be considered treatment works
treating domestic sewage under the
definition, EPA did not propose to
address these facilities in the first round
of part 503 and such facilities would
not, therefore, be required automatically
to submit permit applications after the
first round of part 503 is published. EPA
can, however, individually request
permit applications and issue these
facilities permits on a case-by-case basis
when necessary to protect public health
and the environment (54 FR 18726-
18728). When technical standards are
promulgated that do apply to these
facilities, they will have to comply with
the permit application requirements of
today's rule. The extent to which
industrial treatment works that treat
domestic wastes generated off-site are
covered by the part 503 rule, is
addressed in the part 503 rulemaking,
published in the Federal Register on or
near the same date as today's final rule.
If part 503 applies to these facilities,
they will be required to submit permit
applications according to the deadlines
established in today's final rule.
Treatment works treating domestic
sewage also include owners or operators
of disposal facilities such as sewage
sludge incinerators, monofills, and
surface disposal sites. These facilities
must also apply for a permit. Monofills
and surface disposal sites are "lands
dedicated to the disposal of sewage
sludge" (54 FR 18726). Facilities that
send the sewage sludge they generate to
a treatment or disposal facility must also
submit a permit application. The
permitting authority has the flexibility
to cover both the generator and the
treatment/disposal facility in one permit
or separate permits (including covering
one or both under general permits).
Under the Federal program, the
definition of treatment works treating
domestic sewage does not extend
automatically to land where sewage
sludge is beneficially used, such as farm
land and home gardens (54 FR 18726),
Thus, permits would not be required for
such site owners (except in an unusual
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9407
situation where the site-owner was
designated as a treatment works treating
domestic sewage by EPA under
§ 122.1(b)(4)). EPA cannot envision a
situation where it would issue a permit
to a home gardener who uses sewage
sludge products as a fertilizer or soil
conditioner.
Another commenter was concerned
about how this rule affects those
facilities that send sewage sludge to
municipal solid waste landfills
(MSWLFs). These landfills are regulated
under the part 258 regulations
promulgated jointly under RCRA and
the CWA (56 FR 50978). Part 258
establishes minimum criteria for
MSWLFs, including location
restrictions, facility design and
operating criteria, groundwater
monitoring requirements, corrective
action requirements, financial assurance
requirements, and closure and post-
closure care requirements.
Requirements differ for new and
existing MSWLFs. Regulations for
permitting MSWLFs will be contained
in a separate rulemaking.
This commenter also pointed out that
the CWA does not allow the issuance of
a RCRA Subtitle D permit to operate as
an adequate substitute for NPDES
sewage sludge permit conditions for the
sewage sludge generator. EPA generally
agrees that a MSWLF's permit would
not, in most circumstances satisfy the
CWA requirements for the generator's
permit to include conditions to
implement the sewage sludge
regulations. The actual MSWLF will
continue to be covered under part 258
and will not be required to apply for a
permit under the part 122, 123, or 501
permitting regulations. However, EPA
expects sewage sludge generators who
send their sewage sludge to MSWLFs to
have some sewage sludge requirements
in their NPDES permits. These facilities
must submit permit applications in
accordance with today's final rule. Part
503 proposed to address requirements
for sewage sludge going to MSWLFs, but
the Agency decided that it was not
feasible to develop pollutant-specific
limits for this sewage sludge.
Consequently, EPA established, in the
case of sewage sludge co-disposed with
municipal solid waste, a performance
standard under section 405(d)(3) of the
CWA. EPA determined that the
requirements established in part 258
(e.g., liners and leachate systems) will
ensure that pollutants are not released
into the environment and that public
health and the environment are
adequately protected.
Part 503 proposed to require that the
generating facilities ensure that their
sewage sludge meets the part 258
requirements and that the sewage sludge
only be sent to State-permitted MSWLFs
(54 FR 5794). In other words, each
treatment works treating domestic
sewage must ensure that the sewage
sludge it sends to a MSWLF for disposal
is not hazardous (§ 258.20) and does not
violate the prohibition on disposal of
liquids in landfills (§ 258.28).
Furthermore, sewage sludge that is used
as cover for a MSWLF must be suitable
for that purpose (§ 258.21). Facilities
that send their sewage sludge to
MSWLFs must apply for permits in
accordance with today's final rule.
C. Permit Application Deadlines
Prior to the promulgation of today's
rule, any POTW with an existing NPDES
permit had to submit permit application
information when its next application
for NPDES permit renewal was due, or
within 120 days of publication of an
applicable sewage sludge standard,
whichever came first (§§ 122.21(c)(2)(i)
and 501.15(d)(l)(ii)(A)). The preamble
discussion to the May 2,1989, notice
(54 FR 18737), made it clear that all
POTWs covered by the part 503
regulation had to submit permit
applications within this 120-day period.
Under §§ 122.21(c)(2)(ii) and
501.15(d)(l)(ii)(B), any other existing
treatment works treating domestic
sewage, not subject to the NPDES
program (i.e., a "sludge-only facility"),
had to also submit the permit
application information within 120 days
of publication of an applicable sewage
sludge standard or when requested by
the Director. For treatment works
treating domestic sewage commencing
operation after an applicable part 503
standard was published,
§§ 122.21(c)(2)(iii) and
501.15(d)(l)(ii)(C) required that permit
applications be submitted at least 180
days prior to the date proposed for
commencing operations.
These application deadlines would
have meant that approximately 16,000
POTWs and an estimated three to five
thousand other treatment works treating
domestic sewage would have had to
submit application information within
120 days after publication of part 503.
EPA did not intend to reopen existing
permits immediately or issue new
permits to all facilities who sent in the
permit application information within
this 120-day period. Rather, EPA's
original intent was to use the
information to identify priorities for
permit modification or issuance. The
May 27,1992, proposal noted that
several changes have occurred since
promulgation of the permit
requirements that make this approach
less necessary and less practical.
First, EPA is working to enhance the
direct enforceability of the part 503
standards. Section 405(e) of the CWA
states that it will be unlawful for anyone
to dispose of sewage sludge except in
accordance with the regulations.
Second, as a result of the National
Sewage Sludge Survey, as well as peer
review and public comment on the
proposed part 503 rulemaking, EPA has
improved knowledge of the prevalence
and relative risks of different sewage
sludge use or disposal practices.
Consequently, the Agency is better
equipped to direct permitting activities
to those treatment works treating
domestic sewage that require priority
attention.
Third, EPA is concerned about
effectively using limited resources.
Completing an initial screening of up to
20,000 applications would be a
monumental task and the Agency does
not believe it to be feasible within a
short time period. Further, much of the
information submitted within 120 days
of when part 503 is published may be
outdated by the time work can actually
begin in evaluating the information and
developing permits. Consequently,
treatment works treating domestic
sewage would likely need to submit
new/updated information.
Several comments were received on
the discussion of this new approach in
the May 27,1992, proposal. One
commenter was concerned with how the
self-implementing nature of part 503
would influence reporting, record
keeping and enforcement. The
monitoring, record keeping and
reporting requirements expected to be
established in part 503 will become
effective within several months after the
rule is published. (Note that part 503
will be published in the Federal
Register on or near the same date as
today's final rule.) These requirements
will provide the baseline data from
which compliance evaluations will be
performed and, where required, upon
which enforcement actions will be
taken. Part 503 is expected to require
the submittal of information necessary
to ascertain compliance and the rule
will outline the minimum requirements
for data collection by the regulated
facilities. These data are then required
to be reported to the EPA after the
effective date of part 503 at the
frequency specified in the regulation.
This will be true even in the absence of
a permit. Therefore, inclusion of
monitoring, record keeping, and
reporting requirements in part 503
enhances the self-implementation or
direct enforceability of part 503.
Permits, when issued, will also include
monitoring, record keeping, and
-------
9408 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
reporting requirements that, in
appropriate circumstances, may be more
comprehensive than part 503.
Other commenters were concerned
about the reliance on the self-
implementing provisions of part 503
and suggested this should not be a
substitute for a strong permitting
program, EPA agrees and will rely
largely on the self-implementing nature
of part 503 until permits can be issued.
The CWA requires the Agency to
include requirements to implement the
part 503 standards in NPDES permits
issued to treatment works treating
domestic sewage. Furthermore, the
Agency has the authority to issue
permits to facilities without NPDES
permits under section 405(f)(2) of the
CWA. In addition, the Agency believes
that permits are necessary for several
other reasons. For sludge-only facilities,
permits are an effective means of
bringing newly-regulated facilities into
the program. Permits add certainty to
each party's obligations by spelling
them out in a single document. Permits
also facilitate compliance by specifying
requirements, denoting how compliance
will bo measured, and providing a time
for questions/challenges to be addressed
through the permit issuance and public
comment process rather than through an
enforcement action. Additionally, a
permit can provide a partial "permit as
a shield" defense for compliance with
the permit (§ 122.25(a) (2)). The process
for public participation, which is a part
of every permit, is also an important
goal of the CWA and it helps to build
public acceptance of the beneficial use
of sewage sludge. Permits can allow
consideration of site-specific factors to
adjust national standards in appropriate
instances (for incinerators, some
standards must be set through a permit).
Furthermore, permits clarify
relationships between additional parties
and the permittee's responsibilities
when other parties are involved. Lastly,
permit "boilerplate" provisions
supplement the technical standards by
establishing general duties for
permittees and identifying additional
specificity. For example, the boilerplate
will contain provisions addressing the
following; The duty to notify the
permitting authority of changes in use
or disposal practices; a reopener clause
allowing the permit to be reopened
when new technical standards are
promulgated; a duty to report
noncompliance and mitigate adverse
environmental consequences of
noncompliance; a duty of proper
operation and maintenance; and
detailed monitoring and reporting
requirements.
One commenter requested that EPA
include information on the interim
program in the final rule, suggesting that
if this program had been fully carried
out, EPA would not experience the
anticipated rush of permit applications
soon after part 503 is published and
hence, the regulations would not need
to be changed. In response to this
suggestion, EPA believes that it made it
clear in the May 2,1989, regulations
that even if a permittee had sewage
sludge limits in a permit when an
applicable sewage sludge use or
disposal standard was published, the
permittee must apply for a new permit
within 120 days of that standard's
publication (54 FR 18737). In addition,
permitting authorities would have
received new information from each
facility, since they would be looking for
specific information to ensure
compliance with the technical standards
of part 503. (Although the interim
program requires the placement of
sewage sludge requirements in permits,
the requirements could not possibly be
the same as the requirements which will
be promulgated under part 503 later this
year.) Section 122.44 (c) (4) specifically
states that permits issued to treatment
works treating domestic sewage must
include a reopener clause to include
applicable standards for sewage sludge
use or disposal. As noted in the
proposed rule, today's final rule does
not delay compliance with the part 503
standards—it merely requires permit
applications to be submitted in phases.
Another commenter suggested that
applications only be submitted when
requested by EPA. EPA does not believe
this is the best approach to requiring
permit applications. The Clean Water
Act generally envisions implementation
of the sewage sludge program through
permits. Since EPA contemplates the
eventual permitting of all treatment
works treating domestic sewage, the
Agency prefers that the submittal of
permit applications be triggered
automatically rather than through
individual letters sent to all treatment
works treating domestic sewage. For
those needing site-specific requirements
to implement part 503, requiring permit
applications within a reasonable time
after part 503 will facilitate compliance
with the statutory deadlines.
One commenter thought that it would
be unwise to delay the submittal of
permit applications if it meant that the
development of "management plans"
would also be delayed. (Because the
proposed regulations did not discuss
"management plans," we assume this
refers to "land application plans" under
§§ 122.21(d)(3)(ii) and 501.15(a)(2)(ix).)
Instead, the commenter suggested that
all treatment works treating domestic
sewage that will be required to apply for
a permit, develop and keep on file a
"management plan" within one year of
promulgation of part 503. The
commenter suggested that if a State
intended to apply for authorization,
such a requirement would expedite and
facilitate a smooth transition in issuing
permits. Furthermore, the commenter
suggested that EPA require notice from
all treatment works treating domestic
sewage when their plans were complete.
EPA does not agree that it is necessary
to require treatment works treating
domestic sewage to develop land
application plans prior to submitting a
permit application. Rather, EPA
intended the plan to be submitted with
the permit application and be subject to
permit issuance procedures—including
the public notice and comment
procedures. By accommodating
applicants that have not yet identified
all land application sites, the land
application plans are meant to fill the
gap in the permit so that permit
modifications are not necessary each
time a new land application site is
chosen. Therefore, EPA believes it is
inappropriate to require the
development of such plans until permit
applications are filed. EPA
recommends, however, that if a
treatment works treating domestic
sewage knows that it will need to do a
land application plan, then it should
begin developing the plan well in
advance of filing the permit application.
As for State programs, nothing
prohibits States from requiring these
plans sooner than when permit
applications are due. Furthermore, EPA
would encourage States intending to
submit programs for approval to
establish State requirements that would
make the transition process easier.
In light of the discussion above, and
in response to comments received on
the proposed rule, EPA is adopting the
proposed approach to phase in permit
application submittals as articulated
below.
1. The First Phase
In the first phase, EPA proposed to
focus on all treatment works treating
domestic sewage required to have (or
requesting) site-specific pollutant limits
as provided in part 503. This first phase
includes several types of treatment
works treating domestic sewage but
targets, in particular, sewage sludge
incinerators.
The proposal stated that focusing on
sewage sludge incinerators first is
appropriate because available data
indicate that, of the most common use
or disposal practices, these facilities
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9409
pose the greatest risk to public health.
Several commenters objected to this
statement and requested to see
supporting data. This statement was
based upon the data developed for the
February 6,1989, proposed part 503
regulations. The supporting document,
"Human Health Risk Assessment for
Municipal Sludge Disposal: Benefits of
Alternative Regulatory Options," is
available for review as part of the docket
to this rule. Appointments to review
this document at EPA Headquarters can
be made by calling Pamela Mazakas at
202/260-6599. This document may also
be purchased through the National
Technical Information Service (NTIS) at
a cost of $43.00 plus shipping and
handling (NTIS #PB89-136626). This
information showed that incineration
was associated with the largest number
of cancer cases and lead-associated
adverse health effects of the use or
disposal practices evaluated at that time
(54 FR 5782). It is important to note that
none of the use or disposal practices
were found to be a significant risk.
Further, the final part 503 standards are
designed to provide an equivalent level
of protection from all use or disposal
practices regulated under that rule.
Other commenters asked for
clarification of what is considered a
treatment works treating domestic
sewage that is required to have (or able
to request) site-specific limits. One
commenter specifically requested how
EPA would classify, for purposes of
seeking site-specific limits, storage
lagoons and injection of sewage sludge
into the soil at a dedicated site on which
no crops are grown. Although EPA
appreciates the complexity of these
issues, the availability of site-specific
limits is determined under part 503 and
these issues will be addressed in the
preamble to part 503. (Note that part 503
will be published in the Federal
Register on or near the same date as
today's final rule.) As discussed below,
today's rule lengthens the time during
which permit applications may be
submitted after part 503 is published.
Permit applicants should have ample
time after part 503 is published to
determine whether site-specific limits
are required or desired.
Under the proposal, EPA noted that
requests for site-specific limits would be
considered after this first round of
permit applications only for good cause.
One commenter disagreed and
suggested that requests for site-specific
limits should be available any time data
supported them. To set permitting
priorities and control the permit
application process, EPA has
determined that it is appropriate to limit
the availability of site-specific requests.
If available data support site-specific
limits, the request should be made when
such data are discovered. If additional
data are discovered after the initial 180-
day period after part 503 is published,
then good cause may exist for
consideration of site-specific limits.
Other examples of good cause include
instances when a treatment works
treating domestic sewage changes its
surface disposal site or switches from
one practice to another (e.g., surface
disposal to incineration).
One commenter raised the issue of
defining "existing" facilities. Unlike the
NPDES program, permits are not
necessary for either existing or new
facilities to operate. Furthermore, the
technical standards are the same for
new and "existing" treatment works
treating domestic sewage. Existing
facilities and new facilities will be
responsible for ensuring compliance
with part 503 within one year after part
503 is published (or two years if
construction is required).
The only real difference between new
and existing facilities is when they have
to apply for permits. An existing facility
must apply for a permit according to
today's rule—within 180 days for a
facility required to have or requesting
site-specific requirements, at the time of
its next NPDES permit renewal (for a
facility with an NPDES permit), or, for
a sludge-only facility, it must submit
limited data within one year and a
complete application within 180 days
from when requested by the permitting
authority. EPA is retaining existing
requirements for new facilities which
must apply for a permit 180 days prior
to beginning operation. This provision
also applies to new "sludge-only"
facilities who must submit full permit
applications 180 days prior to beginning
operation.
The commenter mentioned that it had
a facility under construction now which
should be complete at about the same
time as the publication of part 503. For
purposes of today's rule, EPA will
consider new treatment works treating
domestic sewage as those which began
construction after the publication of an
applicable sewage sludge use or
disposal standard. For this reason, the
commenter's facility would be
considered an existing facility and
would be required to submit its
application within 180 days for site-
specific requirements, at the time of its
next NPDES permit renewal, or it must
submit limited data within one year and
complete applications within 180 days
from when requested by the permitting
authority, as appropriate.
One commenter suggested that EPA at
least require permit applications within
120 days for land application of sewage
sludge that does not meet the "super
clean" sewage sludge criteria
anticipated in the part 503 rule (55 FR
47259). EPA does not agree with the
suggestion to require permit
applications within 120 days of when
part 503 is published for land
application unless sewage sludge meets
"super clean" criteria. EPA expects that
the direct enforceability of the part 503
standards together with associated
record keeping and reporting
requirements will provide protection.
The standards for land application of
sewage sludge which is not "super
clean" will be as protective as the
standards for land application of "super
clean" sewage sludge. Furthermore, if
the permitting authority anticipates a
problem, it has the authority to request
permit applications sooner than the
time frames established under today's
final rule.
For the reasons stated above, EPA is
adopting the proposed requirement for
treatment works treating domestic
sewage required to have (or requesting)
site-specific limits to submit permit
applications within 180 days of when
part 503 is published §§ 122.21(c)(2)(i)
and 501.15(d)(l)(ii) (A). (See discussion
below for further information on the
extension of the time period from 120
days to 180 days.) (Note that part 503
will be published in the Federal
Register on or near the same date as
today's final rule.)
2. The Second Phase
Instead of requiring an immediate
submittal of a complete application
from sludge-only treatment works
treating domestic sewage, EPA proposed
that they submit limited background
information within one year of
publication of an applicable sewage
sludge use or disposal standard. (To the
extent these treatment works treating
domestic sewage were required to have,
or wanted to request, site-specific limits,
EPA proposed that they come forward
during the first phase and submit permit
applications within 180 days of
publication of an applicable sewage
sludge use or disposal standard.)
EPA proposed that these sludge-only
treatment works treating domestic
sewage submit the following
information to the Director:
(1) Name, mailing address and
location of the treatment works treating
domestic sewage;
(2) The operator's name, address,
telephone number, ownership status,
and status as Federal, State, private,
public or other entity;
(3) A description of the sewage sludge
use or disposal practices (including,
-------
9410 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
whore applicable, the location of any
sitos where sewage sludge is transferred
for treatment, use, or disposal, as well
os tho name of the applicator or other
contractor who applies the sewage
sludge to land if different from the
treatment works treating domestic
sowogo, and the name of any
distributors if the sewage sludge is sold
or given away in a bag or similar
enclosure for application to the land, if
different from the treatment works
treating domestic sewage);
(4) Annual amount of sewage sludge
gonorated, treated, used or disposed (dry
weight basis); and
(5) The most recent data the treatment
works treating domestic sewage may
have on the quality of the sewage
sludge.
Some treatment works treating
domestic sewage are not currently
subject to the existing NPDES program
for effluent discharges (i.e., they are
sludge-only facilities). EPA will use this
second phase to create an inventory of
these sludge-only treatment works
treating domestic sewage and to set
permitting priorities.
One commenter suggested that the
limited information being submitted by
sludge-only treatment works treating
domestic sewage is inadequate to set
priorities and that, at a minimum, they
ought to be required to submit sewage
sludge quality data. EPA agrees that
sowaga sludge quality data are
important and proposed in
§§122.21(c)(2)(iii)(E)and
501.15(d)(l)(ii)(C)(5) that existing data
be submitted. EPA believes this
provision is adequate since the
proposed part 503 regulation had self-
implementing monitoring and record
keeping requirements which would
generate data on sludge quality. If, as
anticipated, these monitoring and
record keeping requirements are in the
final rule, they will be effective soon
alter part 503 is published and,
therefore, all treatment works treating
domestic sewage should be generating
now data, which would be available
data required under
§§122.21(c)(2)(iii)(E)and
501.15(d)(l)(ii)(C)(5). EPA believes that
receiving these data from "sludge-only"
treatment works treating domestic
sewage will provide adequate
information to establish permitting
priorities.
EPA believes that it is appropriate to
only require limited data from "sludge-
only" treatment works treating domestic
sowago. As noted above, this data will
servo to inventory the sludge-only
facilities as well as provide the
permitting authority with information to
sat permitting priorities. Additionally,
the permitting authority maintains the
ability to require any treatment works
treating domestic sewage to submit full
permit applications at any time if it
determines a permit is necessary to
protect public health and the
environment. One commenter was not
sure how the permitting authority
would be able to require complete
applications from sludge-only treatment
works treating domestic sewage.
Sections 122.21(c)(2)(iv) and
501.15(d)(l)(ii)(D) of today's final rule
state that the permitting authority
maintains the ability to require permit
applications sooner than the times
defined in the rule—for any treatment
works treating domestic sewage. One
commenter thought these provisions
were inconsistent with the provision
requiring only limited data from sludge-
only treatment treating domestic
sewage. The limited data submitted by
the sludge-only treatment works treating
domestic sewage is only preliminary
data. This limited information will
allow the permitting authority to set
permitting priorities. If the permitting
authority determines that the sludge-
only facility needs to submit a full
permit application, it may request a full
application either after reviewing the
limited data, or prior to the one year
deadline for the submission of the
limited data if necessary. It would not
be necessary for the sludge-only facility
to be in noncompliance before the
permitting authority can request it to
submit a full application. As noted
earlier, the facility may become one of
the permitting authority's priorities
either by the nature of its practice or by
the fact that other facilities already have
permits.
To clarify when sludge-only facilities
must submit their limited data, EPA is
considering the ultimate use or disposal
of a generator's sewage sludge to be the
generator's use or disposal practice—
even if the sewage sludge use or
disposal is carried out by someone else.
Therefore, sludge-only treatment works
treating domestic sewage will have to
submit their information within one
year after publication of part 503 if the
sewage sludge they generate is
ultimately land applied, incinerated in
a sewage sludge incinerator, placed in a
surface disposal site, or disposed in a
MSWLF. For example, if a sludge-only
treatment works treating domestic
sewage generates sewage sludge and
sends that sewage sludge to someone
else's sewage sludge incinerator, the
generating treatment works treating
domestic sewage will still have to
submit its information within one year
after publication of part 503. (In this
case, the incinerator will also be
considered a treatment works treating
domestic sewage and will be required to
submit permit application information
as well.)
A few commenters were concerned
about how sludge-only treatment works
treating domestic sewage will know to
submit information. The sewage sludge
implementation regulations have been
in existence since 1989. EPA has held
numerous workshops in an attempt to
reach most of the regulated community.
EPA will continue its efforts to identify
and notify sludge-only permittees of
their obligations. Realizing that sludge-
only facilities are not part of the existing
NPDES program, EPA will be working
with trade associations and other
organizations to distribute information
on the regulations to this group.
Furthermore, many States already
regulate sludge-only facilities and EPA
intends to work closely with State
agencies to ensure that such facilities
are notified of their requirements under
the Federal program.
In light of the above discussion, EPA
is adopting the proposed changes to
require sludge-only treatment works
treating domestic sewage (not required
to have or requesting site-specific limits)
to submit limited data within one year
after publication of part 503
(§§ 122.21(c)(2)(iii) and
501.15(d)(l)(ii)(C)). (Note that part 503
will be published in the Federal
Register on or near the same date as
today's final rule.)
3. The Third Phase
The third phase consists of treatment
works treating domestic sewage with
NPDES permits not addressed under the
first phase. The proposal required that
these treatment works treating domestic
sewage submit the application
information in accordance with NPDES
permit renewal procedures. Such
procedures require permit applications
at least 180 days before the NPDES
permit is due to expire. Thus, permit
applications would be submitted over
the course of a five year permit cycle.
In the interim period, before permits are
issued to these facilities, the part 503
standards will be directly enforceable,
providing protection to public health
and the environment. Furthermore, if
EPA determines that it is necessary to
require sewage sludge application
information and to reopen a permit
before renewal, it may do so at its
discretion under the authority of 40 CFR
122.62(a) (3) and (7) to protect public
health or the environment.
Several commenters wanted
clarification for situations where an
NPDES permit has been
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9411
administratively continued (or
extended). Today's rule requires NPDES
permittees (not required to have or
seeking site-specific limits) to submit
sewage sludge data at the time of their
next NPDES permit renewal
applications. NPDES permittees,
however, should have been submitting
general information on sewage sludge
with their permit applications since
1989 when part 122 was revised to
require this (54 FR 18716). Therefore,
the permitting authority should already
have basic sewage sludge information
from any NPDES permittee who filed a
permit application after 1989, and
sewage sludge requirements should be
included in the NPDES permit. Such
permittees do not have to automatically
resubmit new data during the term of an
administratively continued permit until
the next permit application is due. EPA,
however, expects the permitting
authority to use its authority to ask for
additional sewage sludge information,
which may be necessary to ensure
compliance with part 503, sooner than
the next regularly scheduled application
deadline under § 122.21(c)(2)(iv).
Likewise, for any facilities which may
be operating under a permit that was
administratively continued prior to
1989, sewage sludge data would not be
required to be submitted until the next
NPDES permit application is due.
Again, the permitting authority should
use its discretion to ensure that
adequate information is included in the
permit application process and to
expeditiously incorporate part 503
requirements into reissued permits.
One commenter was concerned that
permit applications with sewage sludge
information would not be submitted for
up to 6 or 8 years because of the backlog
in permit issuance. Another commenter
suggested that if States fail to seek
program approval, it would take EPA "a
decade or two to do the job which must
surely exceed that envisioned by
Congress." The Agency agrees that it
will not be possible to issue all permits
immediately given limited resources.
EPA believes that sewage sludge
management remains a local concern
that should be handled at the State and
local level. Until States obtain program
approval, EPA will do its best to ensure
that the sewage sludge program is being
implemented in a manner that takes into
account the risks posed by sewage
sludge use or disposal. It is important to
note that the Agency will also continue
to encourage and assist States to assume
responsibility for implementing the
sewage sludge program. The CWA
requires compliance with part 503
within one year after its publication (or
two years if construction is required),
regardless of what is embodied in an
NPDES permit. Thus, EPA's ability to
enforce compliance with the standards
is not wholly dependent upon issuance
of permits.
EPA is adopting the proposed
language to require that permit
applications from these treatment works
treating domestic sewage be submitted
in accordance with NPDES permit
renewal procedures. Such procedures
require permit applications at least 180
days before the NPDES permit is due to
expire. (Sections 122.21(c)(2)(ii) and
D. Time Period for Compiling
Application Data
EPA proposed to focus the application
requirements on those treatment works
treating domestic sewage required to
have (or requesting) site-specific
pollutant limits. Today's final rule has
the same focus. Because 120 days may
be insufficient to generate the necessary
information for site-specific permits,
EPA proposed to extend the time period
to 180 days after publication of part 503.
Two commenters noted that they
appreciated the increase from 120 days
to 180 days but stated that they did not
believe 180 days would be sufficient
either. Similarly, one commenter
suggested that EPA require the
submission of all information except the
site-specific analysis (unless already
completed) within the 180-day period.
This commenter suggested applicants be
required to submit a rationale for the
need for additional time to complete the
site-specific analysis and a schedule for
completing the analysis during the 180-
day period but that the actual analysis
could be submitted later. The Agency
believes that part 503 will be explicit
enough so that facilities will be able to
gather the necessary information. EPA is
driven by the compliance deadlines
required by Congress in the CWA. EPA
believes that the 180-day period
established in today's rule strikes a
balance between Congress's compliance
date and EPA's need to receive complete
information in permit applications for
those facilities whose standards need to
be established on a site-specific basis.
One commenter objected to the
extension from 120 to 180 days for site-
specific applications and wanted to see
more clarification on which applicants .
fall into this group and the potential risk
they pose. As noted earlier in this
preamble, determining which facilities
are required to have (or able to request)
site-specific limit.,, is an issue that will
be determined in the part 503 rule.
Therefore, this will be discussed in the
preamble which accompanies that rule.
Furthermore, now that the Agency has
a better understanding of the likely part
503 requirements, the Agency has
determined that 120 days is too
restrictive and that 180 days is more
appropriate. For example, sewage
sludge incinerators may need to submit
air dispersion data and conduct control
efficiency tests (trial burns) that could
take a considerable period of time to
complete. EPA believes the 180-day
deadline will foster the submittal of
complete and accurate applications.
EPA is adopting the changes as
proposed to extend the time period from
120 days to 180 days after part 503 is
published for treatment works treating
domestic sewage to submit permit
applications.
For consistency, EPA also proposed to
modify § 122.1(b)(4). This provision
states that a user or disposer of sewage
sludge designated as a treatment works
treating domestic sewage must submit a
permit application within 120 days of
being notified by the Regional
Administrator that a permit is required.
EPA proposed to extend this time
period from 120 days to 180 days after
a treatment works treating domestic
sewage is notified that a permit is
required. EPA received no comments on
this change and it is being adopted as
proposed.
For a summary of the general changes
to the existing requirements for when
permit applications have to be
submitted (under parts 122,123, and
501) made by today's rule, see Table II-
1.
TABLE 11-1.—SUMMARY OF GENERAL
CHANGES MADE BY TODAY'S FINAL RULE
Facilities required
to have (or re-
questing) site-
specific limits:
NPDES permit-
tees.
Non-NPDES
permittees
("sludge-
only").
Old require-
ments
Submit sew-
age sludge
application
information
within 120
days after
part 503
promulga-
tion.
Submit sew- .
age sludge
application
information
within 120
days after
part 503
promulga-
tion.
New require-
ments
Submit sew-
age sludge
application
Information
within 160
days after
part 503
publica-
tion *t
Submit sew-
age sludge
application
information
within 180
days after
part 503
publica-
tion *t
-------
9412 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
TABLE 11-1.—SUMMAHY OF GENERAL
CHANGES MADE BY TODAY'S FINAL
RULE—Continued
Facilities not ro-
qtiltod to have
(or requesting)
itta-spociflc Hm-
llsiNPDES per-
mitloos.
Non-NPDES
po (mitloos
fsJudgo-
onry").
Old require-
ments
Submit sew-
age sludge
application
Informatton
within 120
days after
part 503
promulga-
tion.
Submit sew-
age sludge
application
Information
within 120
days after
part 503
promulga-
tion.
New require-
ments
Submit sew-
age sludge
application
Information
at the time
of next
NPDES per-
mit renewal
application t
Submit limited
sewage
sludge Infor-
mation with-
in 1 year
after part
503 publica-
tion t
•Applicant may request site-specific pollutant limits
later upon a showing of good cause.
tTho permitting authority may request that permit
applications be submitted earlier than the times set
forth (n this table. Permit applications are due 180
days after the permitting authority makes such a
request
E. Compliance With the CWA and Part
503
Sovoral commenters expressed
concerns over the part 503 compliance
deadlines (one year after publication or
two years after publication if
construction is required). EPA has no
authority to provide additional time for
compliance since these deadlines were
specifically sot by Congress in section
405(d)(2)(D) of the Clean Water Act.
F. State Programs and the Permitting
Authority
For consistency, EPA proposed to
include the above changes to the
permitting procedures into 40 CFR
123.25(a)(4) by cross-referencing the
part 122 provisions being amended
today. This means that States which
sock approval of a modification to their
NPDES programs to regulate sewage
sludge use or disposal would be
expected to have comparable
regulations as part of their programs.
EPA received no comments on the
proposed change and it is being adopted
nsproposcd.
EPA will be responsible for issuing
permits that implement the sewage
sludgo use or disposal standards, unless
those standards are implemented
through certain other Federal permits or
permits issued by a State with an EPA-
approved sewage sludge management
program. Because no States have
received EPA approval of their State
sewage sludge management programs
yet, EPA will be the permitting
authority initially and all application
information must be submitted directly
to the appropriate EPA Regional offices,
unless notified otherwise by the
Regional office. (Appendix A lists the
addresses for the EPA Regional offices
and the States within each Region.)
One commenter was confused about
where permit applications are to be sent
in "approved States." In States with
approved sewage sludge programs, the
permit application information is
submitted to the State agency which has
been approved by EPA to administer the
federal sewage sludge program in lieu of
EPA. Treatment works treating domestic
sewage should note that a State can
have an approved sewage sludge
program even if it does not have an
approved NPDES program. Similarly,
just because a State has an approved
NPDES program, does not mean it has
an approved sewage sludge program as
well. Questions about the current status
of State program approvals at any
particular time should be directed to
EPA Regional offices.
Currently there are no States with
formally approved sewage sludge
programs, although several are operating
under Memoranda of Agreement with
the EPA Regional Offices for interim
sewage sludge programs. Once the part
503 regulations are final, the interim
programs will no longer be effective and
all sewage sludge data should be
submitted to the Regional EPA Office,
until a State receives formal sewage
sludge program approval. In States with
approved NPDES programs, the part of
the permit application containing
sewage sludge data must be sent to EPA,
while the rest of the permit information
is sent to the State, unless otherwise
directed by the EPA Regional office. To
clarify this further, the ending phrase of
§ 122.21(c)(2)(ii) has been modified to
instruct treatment works treating
domestic sewage with NPDES permits to
submit sewage sludge data "at the time
of their next NPDES permit renewal
application" instead of "with their next
NPDES permit renewal application."
Several commenters requested
clarification on the interaction between
the Federal program and State
programs—specifically addressing
permits, enforcement and reporting. The
Federal program will not supersede or
replace a State program. Rather, until a
State receives formal program approval,
the regulated community may be subject
to both the State and Federal programs.
This could mean that a treatment works
treating domestic sewage could be
required to obtain two permits, conduct
monitoring, and report results—both
under the Federal and State programs.
The Federal permit may include more
stringent requirements than a State
permit, and vice versa. Section 122.l(f)
allows States to have sewage sludge
requirements that are different from, or
more stringent than, those in the Federal
regulations. The State will continue to
enforce its requirements and EPA will
enforce the Federal requirements. In
States with approved sewage sludge
programs, the States will be primarily
responsible for enforcement while EPA
will maintain enforcement and
oversight authority.
Although in the short term treatment
works treating domestic sewage may be
subject to two separate programs, EPA is
working to assist States in their
applications to take on Federally
approved programs so the requirements
can be rolled into one program instead
of two.
G. Technical Correction to § 123.25
On July 28,1986, EPA promulgated
final regulations for application
requirements for facilities that discharge
only non-process wastewater. At 51 FR
26991, EPA redesignated § 122.21(h)-(o)
as (i)-(p) and added a new § 122.21(h).
Conforming changes were not made to
§ 123.25(a)(4) which refers to relevant
portions of section 122. These technical
corrections are being made as part of
today's rule.
III. Regulatory Development Process
A. Executive Order 12291
Under Executive Order 12291, EPA
must judge whether a regulation is
major and, therefore, subject to the
requirement of a Regulatory Impact
Analysis. A major rule is defined as a
regulation that is likely to result in:
(1) An annual effect on the economy
of $100 million or more;
(2) A major increase in the costs or
prices for consumers, individual
industries, Federal, State and local
government agencies, or geographic
regions; or
(3) A significant adverse effect on
competition, employment, investment,
productivity, innovation, or on the
ability of United States-based
enterprises to compete with foreign-
based enterprises in domestic or export
markets.
Today's final rule imposes no new
criteria but rather lessens the burden for
submitting permit applications. Instead
of requiring the submission of all permit
applications within 120 days after the
publication of part 503, the submission
of applications is to be done in phases.
This avoids the potential for a treatment
works treating domestic sewage to have
to submit two applications because
information became outdated before a
permit could be written. Therefore, this
final rule does not constitute a major
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
9413
rulemaking. These regulations were
submitted to the Office of Management
and Budget (OMB) for review.
B. Paperwork Reduction Act
The information collection
requirements contained in this rule
were detailed in Information Collection
Request 226.10. These requirements
have been approved by the Office of
Management and Budget (OMB) under
the provisions of the Paperwork
Reduction Act, 44 U.S.C. 3501 et seq.
and are currently assigned OMB control
number 2040-0086.
Public reporting burden for this
collection of information is estimated at
four to five hours per response, with an
average burden of 4.83 hours per
response, including time for reviewing
instructions, searching existing data
sources, gathering and maintaining the
data needed, and completing and
reviewing the collection of information.
Send comments regarding the burden
estimate or any other aspect of this
collection of information, including
suggestions for reducing the burden, to
Chief, Information Policy Branch, PM-
223Y, U.S. Environmental Protection
Agency, 401 M Street, SW., Washington,
DC 20460; and to the Office of
Management and Budget, Washington,
DC 20503, marked "Attention: Desk
Officer for EPA."
C. Regulatory Flexibility Act
Under the Regulatory Flexibility Act,
5 U.S.C. 601 et seq., EPA is required to
prepare a Regulatory Flexibility
Analysis to assess the impact of its rules
on small entities. No Regulatory
Flexibility Analysis is required,
however, where the head of the agency
certifies that the rule will not have a
significant economic impact on a
substantial number of small entities.
Today's final rule most directly affects
treatment works that use or dispose of
sewage sludge that are already required
to obtain permits under existing Federal
or State programs. Today's rule merely
changes existing regulations to provide
for the submittal of permit applications
in phases. In most cases, small facilities
will have additional time to submit their
applications. Accordingly, I hereby
certify pursuant to 5 U.S.C. 605(b) that
these amendments will not have a
significant impact on a substantial
number of small entities.
List of Subjects
40 CFR Part 122
Administrative practice and
procedure, Confidential business
information, Reporting and
recordkeeping requirements, Sewage
disposal, Waste treatment and disposal,
Water pollution control.
40 CFR 123
Confidential business information,
Hazardous materials, Reporting and
recordkeeping requirements, Sewage
disposal, Waste treatment and disposal,
Water pollution control, Penalties.
40 CFR 501
Confidential business information,
Environmental protection, Reporting
and recordkeeping requirements,
Publicly owned treatment works,
Sewage disposal, Waste treatment and
disposal.
Dated: November 25,1992.
F. Henry Habicht II,
Acting Administrator.
For the reasons set out in the
preamble, parts 122,123, and 501 of
title 40, chapter I of the Code of Federal
Regulations are amended as follows:
PART 122—EPA ADMINISTERED
PERMIT PROGRAMS: THE NATIONAL
POLLUTANT DISCHARGE
ELIMINATION SYSTEM
1. The authority citation for part 122
continues to read as follows:
Authority: The Clean Water Act, 33 U.S.C.
1251 et seq.
2. Section 122.1 is amended by
adding an OMB control number to the
end of the section and by revising the
second sentence of paragraph (b)(4) to
read as follows:
§ 122.1 Purpose and scope.
*****
(b)* * *
(4) * * * Any person designated as a
"treatment works treating domestic
sewage" shall submit an application for
a permit under § 122.21 within 180 days
of being notified by the Regional
Administrator that a permit is required.
(Approved by the Office of Management and
Budget under OMB control number 2040-
0086.)
3. Section 122.21 is amended by
redesignating paragraphs (c)(2) (i), (ii),
and (iii) as (c)(2) (ii), (iii), and (v)
respectively and revising newly
redesignated paragraphs (c)(2) (ii) and
(iii); and adding new paragraphs (c)(2)(i)
and (c)(2)(iv) to read as follows:
§ 122.21 Application for a permit
(applicable to State programs, see §123.25).
*****
(c)* * *
(2) Permits under section 405(f) of
CWA. (i) Any existing "treatment works
treating domestic sewage" required to
have, or requesting site-specific
pollutant limits as provided in 40 CFR
part 503, must submit the permit
application information required by
paragraph (d)(3)(ii) of this section
within 180 days after publication of a
standard applicable to its sewage sludge
use or disposal practice(s). After this
180 day period, "treatment works
treating domestic sewage" may only
apply for site-specific pollutant limits
for good cause and such requests must
be made within 180 days of becoming
aware that good cause exists.
(ii) Any treatment works treating
domestic sewage" with a currently
effective NPDES permit, not addressed
under paragraph (c)(2)(i) of this section,
must submit the application information
required by paragraph (d)(3)(ii) of this
section at the time of its next NPDES
permit renewal application. Such
information must be submitted in
accordance with paragraph (d) of this
section.
(iii) Any other existing "treatment
works treating domestic sewage" not
addressed under paragraphs (c)(2) (i) or
(ii) of this section must submit the
information listed in paragraphs
(c)(2)(iii) (AHE) of this section, to the
Director within 1 year after publication
of a standard applicable to its sewage
sludge use or disposal practice(s). The
Director shall determine when such
"treatment works treating domestic
sewage" must apply for a permit.
(A) Name, mailing address and
location of the "treatment works treating
domestic sewage;"
(B) The operator's name, address,
telephone number, ownership status,
and status as Federal, State, private,
public or other entity;
(C) A description of the sewage sludge
use or disposal practices (including,
where applicable, the location of any
sites where sewage sludge is transferred
for treatment, use, or disposal, as well
as the name of the applicator or other
contractor who applies the sewage
sludge to land, if different from the
"treatment works treating domestic
sewage," and the name of any
distributors if the sewage sludge is sold
or given away in a bag or similar
enclosure for application to the land, if
different from the "treatment works
treating domestic sewage");
(D) Annual amount of sewage sludge
generated, treated, used or disposed (dry
weight basis); and
(E) The most recent data the
"treatment works treating domestic
sewage" may have on the quality of the
sewage sludge.
(iv) Notwithstanding paragraphs (c)(2)
(i), (ii), or (iii) of this section, the
-------
9414 Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations
Director may require permit
applications from any "treatment works
treating domestic sewage" at any time if
the Director determines that a permit is
necessary to protect public health and
the environment from any potential
adverse effects that may occur from
toxic pollutants in sewage sludge.
PART 123—STATE PROGRAM
REQUIREMENTS
4. The authority citation for part 123.
continues to read as follows:
Authority: Clean Water Act, 33 U.S.C. 1251
etseq.
5. Section 123.25 is amended by
revising paragraph (a)(4) to read as
follows:
§123.25 Requirements for permitting.
(a)* * *
(4) §122.21 (a)-(b), (c)(2), (e)-(k), and
(mHp)—(Application for a permit);
PART 501—STATE SLUDGE
MANAGEMENT PROGRAM
REGULATIONS
6. The authority citation for part 501
continues to read as follows:
Authority: Cloan Water Act, 33 U.S.C. 1251
et seq.
7. Section 501.15 is amended by
rodosicnating paragraphs (d)(l)(ii) (A),
(B) and (C) as paragraphs (d)(l)(ii) (B),
(C) and (E) respectively and revising
newly designated paragraphs (d)(l)(ii)
(B) and (C); and adding new paragraphs
(d)(l)(ii)(A) and (d)(l)(ii)(D) to read as
follows:
§501.15 Requirements for permitting.
*****
(d) * - *
CD* * *
(ii) (A) Any existing "treatment works
treating domestic sewage" required to
have (or requesting) site-specific
pollutant limits as provided under 40
CFR part 503, must submit the permit
application information required by
paragraph (a) (2) of this section within
180 days after publication of a standard
applicable to its sewage sludge use or
disposal practice(s). After this 180-day
period, "treatment works treating
domestic sewage" may only apply for
site-specific pollutant limits for good
cause and such requests must be made
within 180 days of becoming aware that
good cause exists.
(B) Any "treatment works treating
domestic sewage" with a currently
effective NPDES permit, not addressed
under paragraph (d)(l)(ii)(A) of this
section, must submit the application
information required by paragraph (a)(2)
of this section when the next
application for NPDES permit renewal
is due.
(C) Any other existing "treatment
works treating domestic sewage" not
addressed under paragraphs (d)(l)(ii)
(A) or (B) of this section must submit
the information listed in paragraphs
(d)(l)(ii)(C)(3)-(5) of this section, to the
Director within one year after
publication of a standard applicable to
its sewage sludge use or disposal
practice(s). The Director shall determine
when such "treatment works treating
domestic sewage" must apply for a
permit.
(1) Name, mailing address and
location of the "treatment works treating
domestic sewage";
(2) The operator's name, address,
telephone number, ownership status,
and status as Federal, State, private,
public or other entity;
(3) A description of the sewage sludge
use or disposal practices (including,
where applicable, the location of any
sites where sewage sludge is transferred
for treatment, use, or disposal, as well
as the name of the applicator or other
contractor who applies the sewage
sludge to land if different from the
"treatment works treating domestic
sewage," and the name of any
distributors if the sewage sludge is sold
or given away in a bag or similar
enclosure for application to the land, if
different from the "treatment works
treating domestic sewage");
(4) Annual amount of sewage sludge
generated, treated, used or disposed (dry
weight basis); and
(5) The most recent data the
"treatment works treating domestic
sewage" may have on the quality of the
sewage sludge.
(D) Notwithstanding paragraphs
(d)(l)(ii) (A), (B), or (C) of this section,
the Director may require permit
applications from any "treatment works
treating domestic sewage" at any time if
the Director determines that a permit is
necessary to protect public health and
the environment from any potential
adverse effects that may occur from
toxic pollutants in sewage sludge.
*****
Editorial Note: This appendix will not
appear in the Code of Federal Regulations.
Appendix A—List of Regional Sewage
Sludge Contacts
Region 1
(Maine, New Hampshire, Vermont,
Connecticut, Massachusetts, Rhode Island)
Thelma Hamilton, Municipal Evaluation
Section (WMC), Water Management Division,
U.S. EPA—Region I, JFK Federal Building,
Boston, MA 02203, Phone: (617) 565-3569.
Region 2
(New York, New Jersey, Puerto Rico, Virgin
Islands)
Alia Roufaeal, Water Management
Division, U.S. EPA—Region II, 26 Federal
Plaza, room 837, New York, NY 10278,
Phone: (212) 264-8663.
Region 3
(Delaware, Virginia, West Virginia, District of
Columbia, Maryland, Pennsylvania)
Ann Carkhuff, Permits Enforcement
Branch, Water Management Division
(3WM55), U.S. EPA—Region III, 841
Chestnut Street, Philadelphia, PA 19107,
Phone: (215) 597-9406.
Region 4
(Alabama, Florida, Georgia, Kentucky,
Mississippi, Tennessee, North Carolina,
South Carolina)
Vince Miller, Municipal Facilities Branch,
Water Management Division, U.S. EPA—
Region IV, 345 Courtland Street, Atlanta, GA
30365, Phone: (404) 347-2391.
Region 5
(Indiana, Illinois, Michigan, Wisconsin,
Ohio, Minnesota)
John Colletti, Water Quality Branch, Water
Division (5WQP-16J), U.S. EPA—Region V,
77 West Jackson Boulevard, Chicago, IL
60604-3590, Phone: (312) 886-6106.
Region 6
(Arkansas, Louisiana, New Mexico,
Oklahoma, Texas)
Stephanie Kordzi, Water Management
Division (6-WPM), U.S. EPA—Region VI,
1445 Ross Avenue, 12th Floor, suite 1200,
Dallas, TX 75202-2733, Phone: (214) 655-
7520.
Region 7
(Iowa, Kansas, Missouri, Nebraska)
John Dunn, Water Compliance Branch,
Water Management Division, U.S. EPA—
Region VII, 726 Minnesota Avenue, Kansas
City, KS 66101, Phone: (913) 551-7594.
Region 8
(Wyoming, Utah, North Dakota, South
Dakota, Colorado, Montana)
Bob Brobst, NPDES Branch (8WM-C),
Water Management Division, U.S. EPA—
Region VIII, 999-18th Street, Denver Place—
suite 500, Denver, CO 80202-2405, Phone:
(303) 293-1627.
Region 9
(California, Nevada, Arizona, Hawaii, Guam,
American Samoa, North Mariana Islands,
Pacific Trust Territories)
Lauren Fondahl, Pretreatment Section (W-
5-2), Water Management Division, U.S.
EPA—Region IX, 75 Hawthorne Street, San
Francisco, CA 94105, Phone: (415) 744-1909.
Region 10
(Oregon, Washington, Idaho, Alaska)
Technology/Standards Questions:
Dick Hetherington, Water Permits Section
(WD-134), Water Management Division, U.S.
EPA—Region X, 1200 6th Avenue, Seattle,
WA 98101, Phone: (206) 553-1941.
Permit Questions:
-------
Federal Register / Vol. 58, No. 32 / Friday, February 19, 1993 / Rules and Regulations 9415
Laura Felten, Water Permits Section (WD-
134), Water Management Division, U.S.
EPA—Region X, 1200 6th Avenue, Seattle,
WA 98101, Phone: (206) 553-1647.
[FR Doc. 93-3 Filed 2-18-93; 8:45 am]
BILLING CODE 6560-50-M
U.S. GOVERNMENT PRINTING OFFICE: 1993—
34.6-51*!
-------
-------
-------
-------
-------
------- |