Standards for the Use or Disposal of Sewage Sludge

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 503

[FRL-4842-8]

Standards for the Use or Disposal of Sewage Sludge

AGENCY: U.S. Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: On November 25, 1992, pursuant to section 405 of the Clean

Water Act (CWA), EPA promulgated a regulation to protect public health

and the environment from reasonably anticipated adverse effects of

certain pollutants in sewage sludge (February 19, 1993). This

regulation established requirements for the final use or disposal of

sewage sludge when: (1) The sludge is applied to the land either to

condition the soil or to fertilize crops grown in the soil; (2) the

sludge is disposed on land by placing it in surface disposal sites; and

(3) the sludge is incinerated. Today's action amends this regulation

with respect to two aspects of the rule pending EPA's reconsideration

of certain issues. The issues under reevaluation concern the

appropriate pollutant limits for molybdenum in sewage sludge when land

applied and the requirement for certain sewage sludge incinerators to

monitor incinerator emissions continuously for total hydrocarbons

(THC).

EFFECTIVE DATE: February 19, 1994.

FOR FURTHER INFORMATION CONTACT: Alan Hais, Chief, Sludge Risk

Assessment Branch, Health and Ecological Criteria Division (4304),

Office of Science and Technology, U.S. Environmental Protection Agency,

401 M Street, SW., Washington, DC 20460, telephone (202) 260-5389.

SUPPLEMENTARY INFORMATION:

A. Authority

Today's rule is being promulgated under the authority of section

405 of the Clean Water Act (CWA). Section 405(d) requires EPA to

establish management practices and numerical limits adequate to protect

public health and the environment against reasonably anticipated

adverse effects of toxic pollutants in sewage sludge. Section 405(e)

prohibits any person from disposing of sludge from a publicly-owned

treatment works or other treatment works treating domestic sewage

except in compliance with the section 405 regulations.

B. Amendment of Pollutant Limits for Molybdenum When Land Applied

On November 25, 1992, the U.S. Environmental Protection Agency

promulgated, pursuant to section 405 of the Clean Water Act, Standards

for the Use or Disposal of Sewage Sludge (40 CFR part 503) published in

the Federal Register on February 19, 1993 (58 FR 9248). This regulation

establishes requirements for the final use or disposal of sewage sludge

that are codified at 40 CFR part 503. By letter dated May 25, 1993,

Climax Metals Company filed a petition with the Agency asking that EPA

reconsider the molybdenum pollutant limits for sewage sludge when it is

applied to the land and to stay the February 19, 1994, compliance date

for these pollutant limits pending reconsideration. Subsequently, on

June 25, 1993, Climax Metals Company, American Mining Congress, The

Chem-Met Company, Eastern Technologies, Inc., Gulf Coast Chemical,

Jamestown Chemical Company, Inc., Midland Research Labs, Inc., and

North Metals and Chemical Company, generators or users of molybdenum,

filed a petition with the United States Court of Appeals for the 10th

Circuit seeking review of the land application pollutant limits for

molybdenum in the part 503 Rule. This petition for review was

subsequently transferred to the D.C. Circuit.

The molybdenum cumulative pollutant loading rate (CPLR) promulgated

at Table 2 of Sec. 503.13 in the final part 503 rule is 18 kg of

molybdenum per hectare of land. The CPLR was determined from Pathway 6

of the land application risk assessment. Pathway 6 evaluates the amount

of a pollutant in sewage sludge that is protective of livestock and

wild animals that consume plants grown on sludge-amended soil. In the

case of molybdenum, the CPLR is designed to protect cattle from

molybdenosis. The major concern that Climax and others have brought to

the Agency's attention is related to the studies used to assess

exposure conditions and the exposure assumptions for the establishment

of the molybdenum CPLR for land application of sewage sludge. In

particular, Climax and others questioned the use of the data from the

Pierzynski and Jacobs (1986) study to determine the crop uptake slope

used in the Pathway 6 risk assessment. These interested parties state

that this approach results in an overprotective molybdenum limit

because the sludges used in the study were highly contaminated with

molybdenum (1500 mg molybdenum per kg of sewage sludge, while sewage

sludge usually contains 40 mg/kg) and because the Pierzynski and Jacobs

data were inappropriately weighted with data from only one other study

(Soon and Bates, 1985).

EPA has reviewed Climax's request and has evaluated additional data

and additional information submitted by Climax supporting a different

crop uptake slope for molybdenum. Based on this preliminary evaluation,

EPA is amending part 503 to delete the molybdenum pollutant limits in

Tables 2, 3, and 4 of Sec. 503.13 pending its reconsideration of

appropriate molybdenum pollutant limits. EPA's preliminary review of

the data indicates the appropriateness of reevaluation of the

cumulative pollutant loading rate for molybdenum established in Table 2

of Sec. 503.13 of the February 19, 1993 rule. Because the molybdenum

cumulative pollutant loading rate is used to develop the molybdenum

pollutant concentration limit and annual pollutant loading rate in

Tables 3 and 4 of Sec. 503.13, respectively, EPA is also amending these

tables to remove the molybdenum pollutant limits.

As noted, the molybdenum limits in Tables 2, 3 and 4 were

determined from a risk assessment of Pathway 6 and are designed to

protect animals consuming feed crops grown on sludge-amended soil from

molybdenosis. Specifically, EPA, using a mathematical algorithm,

calculated what quantity of molybdenum in sewage sludge per hectare of

land could be added to the soil without resulting in exceeding the

threshold in crops fed to domesticated animals that is associated with

molybdenosis. That calculation is dependent on three variables. These

are the threshold level of molybdenum in feed crops associated with

molybdenosis, the background level of molybdenum in feed crops and the

relationship between molybdenum added to the soil from sewage sludge

and the resulting level in feed crops.

EPA has reviewed the data it used to establish the molybdenum

limits, information submitted by Climax and others and additional

information the Agency has obtained. EPA has concluded that the

molybdenum limits are highly sensitive to how the molybdenum data base

used in the part 503 regulation was treated. An example illustrates why

the data are sensitive to the method used in the calculation. Assume

that two field studies are used to calculate the uptake of molybdenum

by feed crops grown on sludge-amended soil. One study shows low

molybdenum uptake levels while the second shows high uptake. If the

study with low molybdenum uptake levels includes only three data points

while the study showing high uptake contains 20 data points,

calculation of a single uptake value from the studies will differ

depending on how the data points in the individual studies are treated.

If all data points are weighted equally, then the results will be most

heavily influenced by the high uptake data points. Contrarily, if the

results are averaged for each study separately and then the studies,

rather than data points, weighted equally, the influence of the high

uptake data is mitigated.

Given the limited number of studies relied upon for the part 503

molybdenum limits and the resulting sensitivity of the results to the

method adopted for weighting data points in those studies, EPA

determined that it should reconsider these limits. A preliminary review

of additional field studies suggests that use of data from sewage

sludge that is highly contaminated by molybdenum may yield results that

could overpredict crop uptake and background molybdenum levels in feed

crops at the lower levels of molybdenum required by part 503. This

leads the Agency to conclude that the limits adopted in Tables 2, 3,

and 4 may be more restrictive than required to protect public health

and the environment because of both an inappropriately high background

molybdenum level in feed crops and molybdenum uptake rate. This

information has led the Agency to conclude that it should reevaluate

its determination of the molybdenum pollutant limits for land

application of sewage sludge.

EPA has concluded that amending its regulation to delete the

current land application molybdenum pollutant limits pending

reconsideration will not adversely affect public health and the

environment for the following reasons. First, EPA is not modifying the

ceiling concentration limit for molybdenum (75 milligrams per kilogram

of sewage sludge on a dry weight basis) in Table 1 of Sec. 503.13.

Sewage sludge that is land applied must have a molybdenum concentration

equal to or less than this limit. Sewage sludge that exceeds this level

cannot be land applied. Under a worst case scenario of 75 milligrams of

molybdenum per kilogram of dry sewage sludge, if sewage sludge is

applied at a rate of 10 metric tons of sewage sludge (dry weight basis)

per hectare of land annually, it would take 24 years to reach the

cumulative pollutant load of 18 kilograms per hectare for molybdenum--

the CPLR adopted in Table 2 of Sec. 503.13 in the final rule. Because

EPA plans to propose and promulgate a new molybdenum cumulative

pollutant loading rate in the near future, a new molybdenum pollutant

concentration limit and a new annual pollutant loading rate (APLR),

even if EPA concludes the same or lower limits are necessary to protect

public health and the environment, the likelihood that the molybdenum

in sewage sludge applied to the land during the time EPA reevaluates

the molybdenum CPLR would harm public health and the environment is

extremely low.

Similarly, under this worst case scenario, sewage sludge sold or

given away in a bag or other container for application to the land

(e.g., for use on lawns or home gardens) is limited to an annual

application rate of 12 dry metric tons per hectare. This application

rate is calculated based on the ceiling concentration of 75 mg

molybdenum per kg of dry sewage sludge and the annual pollutant loading

rate of 0.9 kg per hectare per 365 day period listed in Table 4 of

Sec. 503.13. Application rates above this amount would cause an

exceedence of the molybdenum annual pollutant loading rate. However,

the molybdenum pollutant limit on which the APLR is based is designed

to protect animals consuming forage grown on sludge amended soils from

molybdenum toxicity. The likelihood of cattle consuming feed crops

grown on a lawn or home garden is small. In the multi-pathway risk

assessment, the next most limiting pathway for molybdenum is Pathway 3,

the ingestion of pure sewage sludge by a toddler. Pathway 3 is a more

realistic concern for sewage sludge sold or given away in a bag or

other container. The pollutant limit for this pathway is 400 milligrams

of molybdenum per kilogram of dry sewage sludge, well above the ceiling

concentration limit of 75 mg molybdenum per kg of dry sewage sludge.

Because sewage sludge cannot be applied to the land if the molybdenum

concentration is greater than 75 mg molybdenum per kg of dry sewage

sludge, the toddler who may inadvertently ingest sewage sludge is

protected during the time the Agency reconsiders the molybdenum

pollutant limits. Therefore, today's amendments to the pollutant limits

in Tables 2, 3, and 4 of Sec. 503.13 will not threaten public health or

the environment for land application of either bulk sewage sludge sold

or sewage sludge sold or given away in a bag or other container.

C. Modification of the Applicability of the Continuous Emission

Monitoring Requirements for Total Hydrocarbons for Certain Incinerators

On July 17, 1993, Gloucester County Utilities, Stony Brook Regional

Sewerage Authority, Township of Wayne, Pequannock, Lincoln Park and

Fairfield Sewerage Authority, Somerset Raritan Valley Sewerage

Authority, Bayshore Regional Sewerage Authority, and the State of New

Jersey filed a petition with the D.C. Circuit seeking review of the

part 503 regulation. These petitioners challenged, among other things

the failure of the part 503 regulation to allow site-specific sewage

sludge incinerator emissions limits and the failure to allow State-

imposed emissions limitations, including monitoring and reporting

requirements, to replace the part 503 requirements. The petitioners

argue that the requirements to demonstrate compliance with a 100 ppm

total hydrocarbon (THC) operational standard through continuous

monitoring of THC emissions should be changed.

Currently, the State of New Jersey requires that the exit gas from

the petitioners' sewage sludge incinerators meet a 100 ppm carbon

monoxide (CO) limit corrected for zero percent moisture and to seven

percent oxygen. The State also requires the petitioners to monitor the

exit gas continuously for CO. For these reasons, the petitioners asked

for relief from the requirement to monitor THC continuously. To

demonstrate compliance with the 100 ppm THC operational standard, the

incinerator management practices in Sec. 503.45(a) require installation

of a continuous equipment THC monitor. In the petitioners' view,

installation of this instrument is not needed because any sewage sludge

incinerator complying with State of New Jersey 100 ppm emissions

limitation and continuous CO monitoring requirements will comply with

the 100 ppm THC operational standard.

EPA concluded that it is appropriate to reconsider its requirement

for the continuous monitoring of THC in the case of certain

incinerators. Based on a reassessment of information on THC emissions

and CO emissions from certain types of sewage sludge incinerators, EPA

has preliminary determined that incinerators that meet a 100 ppm CO

emission limitation will easily achieve a 100 ppm THC operational

standard. In these circumstances, EPA determined that requiring such

incinerators to install and maintain continuous THC monitors was unduly

burdensome and wasteful and would not result in increased environmental

benefits. Accordingly, EPA finds there is good cause to amend its

regulation, effective immediately, to authorize the demonstration of

compliance with the 100 ppm THC operational standard by meeting a 100

ppm CO limit and by monitoring the exit gas continuously for CO during

the interim period of reconsideration. Therefore, EPA is today issuing

a final rule amending the applicability provision of the part 503--

subpart E--Incineration to modify the applicability of certain

management practices, frequency of monitoring requirements and

recordkeeping requirements for sewage sludge incinerators meeting

certain conditions.

As a result of the amendment, the following requirements will not

apply to sewage sludge incinerators meeting defined conditions: the

management practice in Sec. 503.45(a); the frequency of monitoring

requirements for THC concentration in Sec. 503.46(b); and the

recordkeeping requirements for THC concentration in Sec. 503.47 (c) and

(n). The management practice in 503.45(a) requires the installation of

a continuous emissions monitor for total hydrocarbons. The monitoring

requirements of Sec. 503.46(b) concern THC concentration in the exit

gas. The recordkeeping requirements in Sec. 503.47 (c) and (n) deal

with the total hydrocarbons concentration in the exit gas from the

sewage sludge incinerator stack and with a calibration and maintenance

log for THC concentration in the exit gas.

The requirements outlined above do not apply to sewage sludge

incinerators in the following circumstances. The sewage sludge

incinerator must achieve a CO concentration in the exit gas of 100 ppm

(monthly average) or lower, corrected for zero percent moisture and to

seven percent oxygen. The incinerator owner/operator also must monitor

the exit gas continuously for CO, keep records on the CO emissions,

and, in certain cases, report the monthly average CO concentration

annually to the permitting authority.

EPA concluded there is good cause for taking today's action because

current data support the petitioners' assertion that the THC

concentration in the exit gas from the sewage sludge incinerators

described above will comply with the 100 ppm (monthly average) THC

operational standard in part 503 when the monthly average CO

concentration in the exit gas is equal to or less than 100 ppm.

D. Procedural Requirements

EPA has reviewed the two requests discussed above and concluded

that: (1) The molybdenum CPLR, pollutant concentration limit, and APLR

for land application should be reconsidered based on the new

information, and (2) the THC operational standard in Sec. 503.44(c)

will be achieved if a CO limit of 100 ppm is met. Accordingly, EPA is

today taking final action amending its part 503 regulation. EPA's

action amends the molybdenum pollutant limits for land application in

Tables 2, 3, and 4 of Sec. 503.13 and the applicability of various part

503 requirements related to THC in Sec. 503.45, Sec. 503.46, and

Sec. 503.47 for certain incinerators until such time as the Agency has

an opportunity to study these issues further. At the completion of the

studies, EPA will decide whether to propose new molybdenum pollutant

limits and whether further amendments to part 503 are needed concerning

the monitoring of CO to demonstrate compliance with the THC operational

standard in lieu of monitoring THC continuously.

Section 553 of the Administrative Procedures Act provides that when

an agency for good cause finds that notice and public procedure are

impracticable, unnecessary or contrary to the public interest, it may

first issue a rule without providing notice and comment. In addition,

the agency may make the rule effective immediately. EPA has concluded

here that it should both amend its part 503 regulation as described

without providing for notice and comment and make these changes

effective immediately.

1. Notice and Comment

By today's action, the Agency avoids the possibility that some

treatment works treating domestic sewage would be required to comply

with certain numerical limits for molybdenum in sewage sludge that is

land applied. The Agency has concluded at this juncture that these

limits may be too stringent and consequently should be reconsidered.

Given the pendency of the compliance deadline for the land application

requirements, it would be impracticable to provide notice and comment.

Further, the public interest would suffer to the extent that treatment

works treating domestic sewage incurred increased costs associated with

compliance with requirements that the Agency determines are not needed

to protect public health and the environment. Given the retention of

the ceiling limit on molybdenum in sewage sludge which may be applied

to the land, EPA has concluded that public health and the environment

will be adequately protected while the Agency is reconsidering what are

the appropriate molybdenum limits for Tables 2, 3 and 4 of Sec. 503.13.

Further, in the case of the amendments to the requirements for

sewage sludge incinerators, the Agency has similarly concluded that

notice and comment is impracticable and contrary to the public

interest. EPA has concluded that the public interest will suffer if

sewage sludge incinerators that achieve a 100 ppm CO level, as

demonstrated by continuous CO monitoring, are also required to install

THC monitors. Based on its evaluation, EPA has concluded that, if

incinerators are meeting a 100 ppm CO level, the likelihood is

substantial that such incinerators are well below the 100 ppm THC

operational standard. Given this information and the fact that the

obligation for many of these incinerators to achieve a 100 ppm or lower

CO standard and monitor continuously antedated the promulgation of the

100 ppm THC operational standard, EPA has concluded that the public

interest does not support installation of THC monitors for such

incinerators pending Agency reconsideration.

2. Effective Date

Under section 405 of the CWA, EPA's sewage sludge regulation must

require compliance with the regulation as expeditiously as practicable

but in no case later than 12 months after its publication, unless such

regulation requires construction of new pollution control facilities,

in which case the regulation must require compliance expeditiously, but

not later than two years from publication. The part 503 regulation was

effective on March 22, 1993. In the case of the molybdenum pollutant

limits and the continuous monitoring requirements for THC, the

regulation required compliance by February 19, 1994. Because of the

potential adverse effect on public interest noted above, the Agency has

determined there is good cause for making this regulation effective

immediately.

E. Regulatory Requirements

1. Executive Order 12866

Executive Order 12866 requires EPA to prepare an assessment of the

costs and benefits of any ``significant regulatory action.'' Because

the effect of today's rule is to modify current requirements and

provide additional flexibility to the regulated community, costs to the

regulated community should be reduced or at least remain unchanged.

Consequently, no assessment of costs and benefits is required.

2. Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act, 5 U.S.C. 601-612,

whenever an agency is required to publish a General Notice of

Rulemaking for any proposed or final rule, it must prepare and make

available for public comment a regulatory flexibility analysis that

describes the impact of the rule on small entities (i.e., small

businesses, small organizations, and small governmental jurisdictions).

No regulatory flexibility analysis is required, however, if the head of

the Agency certifies that the rule will not have a significant impact

on a substantial number of small entities.

This action to modify the part 503 regulation promulgated today is

deregulatory in nature and thus will only provide beneficial

opportunities for entities that may be affected by the rule.

Accordingly, I certify that this regulation will not have a significant

economic impact on a substantial number of small entities. This

regulation, therefore, does not require a regulatory flexibility

analysis.

3. Paperwork Reduction Act

There are no reporting, notification, or recordkeeping

(information) provisions in this rule. Such provisions, were they

included, would be submitted for approval to the Office of Management

and Budget (OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et

seq.

List of Subjects in 40 CFR Part 503

Environmental protection, Frequency of monitoring, Incineration,

Land application, Management practices, Pathogens, Pollutants,

Reporting and recordkeeping requirements, Sewage sludge, Surface

disposal and Vector attraction reduction.

Dated: February 18, 1994.

Carol M. Browner,

Administrator.

For the reasons set out in the preamble, part 503 of title 40 of

the Code of Federal Regulations is amended as set forth below:

1. The authority citation for part 503 continues to read as

follows:

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.).

2. Section 503.13 is amended by revising paragraphs (b)(2), (b)(3),

and (b)(4) to read as follows:

Sec. 503.13 Pollutant limits.

(b) * * *

(2) Cumulative pollutant loading rates.

Table 2 of Sec. 503.13.--Cumulative Pollutant Loading Rates

------------------------------------------------------------------------

Cumulative

pollutant

loading

Pollutant rate

(kilograms

per

hectare)

------------------------------------------------------------------------

Arsenic.................................................... 41

Cadmium.................................................... 39

Chromium................................................... 3000

Copper..................................................... 1500

Lead....................................................... 300

Mercury.................................................... 17

Nickel..................................................... 420

Selenium................................................... 100

Zinc....................................................... 2800

------------------------------------------------------------------------

(3) Pollutant concentrations.

Table 3 of Sec. 503.13.--Pollutant Concentrations

------------------------------------------------------------------------

Monthly

average

Pollutant concentrations

(milligrams

per kilogram)1

------------------------------------------------------------------------

Arsenic................................................. 41

Cadmium................................................. 39

Chromium................................................ 1200

Copper.................................................. 1500

Lead.................................................... 300

Mercury................................................. 17

Nickel.................................................. 420

Selenium................................................ 36

Zinc.................................................... 2800

------------------------------------------------------------------------

1Dry weight basis.

(4) Annual pollutant loading rates.

Table 4 of Sec. 503.13.--Annual Pollutant Loading Rates

------------------------------------------------------------------------

Annual

pollutant

loading rate

Pollutant (kilograms

per hectare

per 365 day

period)

------------------------------------------------------------------------

Arsenic................................................... 2.0

Cadmium................................................... 1.9

Chromium.................................................. 150

Copper.................................................... 75

Lead...................................................... 15

Mercury................................................... 0.85

Nickel.................................................... 21

Selenium.................................................. 5.0

Zinc...................................................... 140

------------------------------------------------------------------------

* * * * *

5. Section 503.40 is amended by adding paragraph (c) to read as

follows:

Sec. 503.40 Applicability.

* * * * *

(c) The management practice in Sec. 503.45(a), the frequency of

monitoring requirement for total hydrocarbon concentration in

Sec. 503.46(b) and the recordkeeping requirements for total hydrocarbon

concentration in Sec. 503.47(c) and (n) do not apply if the following

conditions are met:

(1) The exit gas from a sewage sludge incinerator stack is

monitored continuously for carbon monoxide.

(2) The monthly average concentration of carbon monoxide in the

exit gas from a sewage sludge incinerator stack, corrected for zero

percent moisture and to seven percent oxygen, does not exceed 100 parts

per million on a volumetric basis.

(3) The person who fires sewage sludge in a sewage sludge

incinerator retains the following information for five years:

(i) The carbon monoxide concentrations in the exit gas; and

(ii) A calibration and maintenance log for the instrument used to

measure the carbon monoxide concentration.

(4) 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 submit the monthly average carbon monoxide concentrations in

the exit gas to the permitting authority on February 19 of each year.

[FR Doc. 94-4372 Filed 2-24-94; 8:45 am]

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