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This page is composed of a 16-page hand-out distributed at the MDE public meeting on sludge which was held last August at the request of the St. Mary's County Solid Waste Advisory Committee. A table of contents has been added for your convenience.

EPA PART 503 RULE
RISK ASSESSMENT -- THE 14 EXPOSURE PATHWAYS
Hundreds of studies have been done on the issue of metals in sludge, detailing the amount taken up by various kinds of plants and the fate of the metals in the environment. These studies served as the basis for a comprehensive risk assessment of metals in sludge by the U.S. EPA, and the risk assessment in turn resulted in current federal regulatory standards (published in 40 CFR. Part 503) for the use and disposal of sewage sludge. The risk assessment considered every possible way in which the metals could conceivably affect the health of humans, animals, plants, and the environment (air, water, and soil). These are called the 14 pathways, shown below. The limits chosen in the Part 503 Rule protect health and the environment for all 14 pathways.

1. Sludge Soil Plant Human
   (To protect health of humans who eat crops or wild berries, mushrooms grown on sludged land)
2. Sludge Soil Plant Home Gardener
   (To protect health of gardeners who eat plants grown using sludge in their gardens)
3. Sludge Soil Child
   (To protect health of children who eat sludge direct from soil)
4. Sludge Soil Plant Animal Human
   (To protect health of humans who eat meat, eggs, dairy products from domestic or wild animals that eat plants grown on sludged land)
5. Sludge Soil Animal Human
   (To protect health of humans who eat meat from animals that eat sludge direct from soil)
6. Sludge Soil Plant Animal
   (To protect health of animals feeding on plants grown using sludge)
7. Sludge Soil Animal
   (To protect health of animals eating sludge direct from soil)
8. Sludge Soil Plant
   (To protect health of crops grown using sludge)
9. Sludge Soil Soil Biota
   (To protect health of earthworms living in sludged soil)
10. Sludge Soil Soil Biota Predator
    (To protect health of birds that eat worms in sludged soil)
11. Sludge Soil Airborne Dust Human
    (To protect health of tractor operators who apply sludge)
12. Sludge Soil Runoff Water Water Fish Human
    (To protect health of humans who eat fish living in waters near sludged land. and to protect water quality)
13. Sludge Soil Air Human
    (For land application and surface disposal, to protect humans who inhale vapors from sludge) Sludge Incineration Particulate Air Human
    (To protect health of humans living near sludge incinerator)
14. Sludge Soil Ground Water Human
    (For land application and surface disposal, to protect drinking water quality)

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EPA PART 503 RULE
Purpose -- To adequately protect human health and the environment from reasonably anticipated adverse pollutant effects.
What practices does the Part 503 Rule cover?

1. Land application of sewage sludge and septage.
2. Surface disposal of sewage sludge:
   1. In a sludge-only landfill.
   2. By other burial methods.
   3. By letting it remain on the surface for extended periods.
3. Incineration of sewage sludge.

What sludge disposal practice is not covered by Part 503?

-- Disposal in a municipal solid waste landfill (this is covered by EPA's Part 258 Rule on solid waste landfills).

What kinds of requirements are in the Part 503 Rule?

1. General Requirements
2. Pollutant Limits (metals)
3. Management Practices
4. Operational Standards
5. Monitoring
6. Recordkeeping
7. Reporting

The Part 503 Rule is self-implementing; i.e., the requirements must be met regardless of whether a permit has been issued.

All sewerage treatment plants must apply for a Part 503 permit from EPA unless the State's sludge program has been approved by EPA for delegation.

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EPA PART 503 RULE
GENERAL REQUIREMENTS

1. Any person who prepares sewage sludge shall ensure that the applicable requirements of 503 are met when sludge is land applied, placed on a surface disposal site, or burned in a sludge incinerator.
2. Sampling -- the sludge must be sampled and analyzed by EPA approved methods.
3. Any person who applies sewage sludge to the land must comply with the 503 requirements.
4. Must comply with cumulative metal loading rates if applicable.
5. If septage is land applied, the annual application rate must not be exceeded.
6. The person who prepares bulk sludge must inform the land applier of total nitrogen concentration in the sludge. so that a proper agronomic rate can be calculated for land application.
7. The land applier must obtain the following information:
   1. Has bulk sludge subject to cumulative metal loading rates been applied on the land since July 20, 1993?
   2. If so, remaining cumulative rate must be calculated.
8. The person who prepares bulk sludge must give the land applier information on metal concentrations in the sludge so that cumulative metal loading limits are complied with.
9. If bulk sludge is given from the person who prepares (the sludge generator) to another person who prepares (a separate treatment facility, such as a composter or pelletizer, etc.), the giver must inform the receiver of the metal concentrations in the sludge.
10. The land applier of bulk sludge must inform the land owner or lease holder of the land with information needed to comply with 50').
11. If bulk sludge is to be applied in a different state, the person who prepares the sludge (the generator) must provide detailed information to the receiving state.
12. The land applier of bulk sludge must provide written notice and information-nation to the permitting authority for the State before applying the sludge.

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EPA PART 503 RULE
METAL LIMITS
Table I -- Ceiling Concentrations
If the concentration of metals in the sludge (measured by dry weight) exceeds any of the values in this table, then the sludge may not be land applied:

Arsenic	75 mg/kg (ppm)
Cadmium	85 "
Copper	4300 "
Lead	840 "
Mercury	57 "
Molybdenum	75 "
Nickel	420 "
Selenium	100 "
Zinc	7500 "

Table 2 -- Cumulative Metal Loading Rates
If the concentration of metals in the sludge is less than Table I but more than Table 3, then the sludge may be land applied provided records are kept of the amount of metals added to the land from the sludge. Each subsequent time sludge is applied, the amount of metals added to the soil is recalculated to produce a cumulative amount added. If any of the cumulative amounts exceeds the values shown below, then no more sludge may be added to the land:

Arsenic	41 kg per hectare	(37 lbs. per acre)
Cadmium	39"	(35 ")
Copper	1500 "	(1339")
Lead	300 "	(268 ")
Mercury	17 "	(15 ")
Nickel	420 "	(375 ")
Selenium	100 "	(89 ")
Zinc	2800 "	(2500 ")

Table 2 -- PC Metal Concentrations
If the monthly averages of all of the metal concentrations in the sludge are less than those shown in the following table, then the cumulative loading rates (Table 2) do not apply, and cumulative loading rates do not need to be tracked:

Arsenic	41 mg/kg (ppm)
Cadmium	39 "
Copper	1500 "
Lead	300 "
Mercury	17 "
Nickel	420 "
Selenium	100 "
Zinc	2800 "

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EPA PART 503 RULE
ANNUAL LOADING RATES
Table 4 -- Annual Metal Loading Rates

This table applies only to a sludge product that is sold or given away, in a bag or container, such as compost. It does not apply if the sludge has metal concentrations lower than those shown in Table If the product's metal concentrations are greater than those shown in Table 3 but less than those shown in Table 1, then Table 4 applies. If this is the case, then the sludge product must be accompanied by a label stating how much of it may be applied per year. This amount is determined by dividing the metal application rates shown below by 1/1000 the metal concentrations in the sludge product. The lowest of the resulting application rates is the one that determines the annual application rate of the sludge product.

Arsenic	2.0 kg/hectare
Cadmium	1.9 "
Copper	75.0 "
Lead	15.0 "
Mercury	0.85 "
Nickel	21.0 "
Selenium	5.0 "
Zinc	140.0 "

Annual Application Rate for Septage --
There is an annual application rate for domestic septage, based on the following formula:

AAR= N ÷ 0.0026

where AAR is the annual application rate expressed in gallons per acre per year, and N is the amount of nitrogen in pounds per acre per year needed by the vegetation on site.

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EPA PART 503 RULE
MANAGEMENT PRACTICES FOR LAND APPLICATION

1. Bulk sewage sludge may not be land applied if it is likely to adversely affect a threatened or endangered species.
2. Bulk sludge may not be applied on land that is flooded, frozen, or snow-covered so that the sludge enters waters of the U.S., except as otherwise provided by permit.
3. For bulk sludge, a ten meter ('I.' ) ft) buffer zone is required to waters of U.S.
4. Bulk sludge must be applied at an agronomic rate, except for land reclamation sites.
5. A label or instruction sheet is required for sludge products (such as compost) that are sold or given away in bags or containers.

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EPA PART 503 RULE
OPERATIONAL STANDARDS -- PATHOGEN REDUCTION
There are two classes of pathogen reduction: Class A and Class B. Class A treatment is the equivalent of PFRP, and Class B is equivalent to PSRP.

Class B sludge may be applied to farms, forests, reclamation sites, or public contact sites provided that the following site restrictions are met:

1. Wait 14 months before harvesting food crops whose eaten parts are above ground and touch the sludge -- example: tomatoes, cucumbers, lettuce, etc. Please note that this does not apply to grains. In EPA's definitions@, "Food crops" are those eaten primarily by humans, "Feed crops" are those eaten primarily by animals, and "Fiber crops" are crops such as cotton and flax.
2. Wait 20 months before harvesting food crops whose eaten parts are below ground, provided that the sludge was not incorporated into the soil -- example: carrots, radishes, turnips.
3. Wait 38 months before harvesting food crops whose eaten parts are below ground, provided that the sludge was incorporated into the soil. -
4. Wait 30 days before harvesting food crops, feed crops, or fiber crops.
5. Wait 30 days before allowing animals to graze on the land.
6. Wait I year before harvesting turf, unless otherwise specified.
7. Restrict public access to land for I year if the land has a high potential for public exposure -- example: parks, ball fields, golf courses, turf farms, plant nurseries.
8. Restrict public access to land for 30 days if the land has a low potential for public exposure example: agricultural land, forests, or reclamation sites located in rural areas.
9. If septage is applied on farm land, forest, or a reclamation site, D of the above site restrictions apply unless the septage is lime stabilized. If the septage has been lime stabilized, the only site restrictions that apply are I thru 4 above.

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EPA PART 503 RULE
OPERATIONAL STANDARDS -- CLASS A & CLASS B STANDARDS
Class A pathogen reduction standards must be met if sludge is applied to a lawn or home garden, or if it is sold or given away in a bag or container.

Class A requirements --

There are 6 alternative ways to demonstrate that sludge meets Class A standards. All of them require bacteriological testing to document that either fecal coliforms are less than 1000 MPN per gram dry weight, or salmonella is less than 3 MPN per 4 grams dry weight. Generally. the pathogen reduction requirements must be met either prior to or at the same time as vector attraction reduction requirements. The most basic of the 6 alternatives is to demonstrate either the fecal coliform standard or salmonella standard shown above, and to demonstrate that the treatment process is a PFRP (Process to Further Reduce Pathogens) process.

Class B requirements --

There are 3 alternative ways of meeting Class B requirements:

1. Use a PSRP (Process to Significantly Reduce Pathogens) treatment method and use the site restrictions shown earlier.
2. Use a PSRP equivalent treatment method (as determined by the permitting authority) and use the site restrictions.
3. Take 7 samples at the time the sludge is used. The geometric mean of the samples must be either:
   1. Less than 2,000,000 MPN per gram dry weight for fecal coliform,
      
      or
      
      
   2. Less than 2,000,000 CFU per gram dry weight for fecal coliform.

In addition, the site restrictions must be used.


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EPA PART 503 RULE
OPERATIONAL STANDARDS -- VECTOR ATTRACTION REDUCTION
All land applied sludge must meet vector attraction reduction standards in addition to the metal limits and pathogen reduction standards. Only some of the vector attraction reduction standards must be met, depending on the type of sludge and its use. The following is a "menu" of the different ways to meet the vector attraction reduction standards, depending on the circumstances:

1. Reduce volatile solids by 38% or more.
2. If this can't be met, redigest a sample in a lab under specified conditions. If volatile solids have been further reduced by less than 17% after 40 days, the standard has been met. This method applies only to anaerobically digested sludge.
3. For aerobically digested sludge, if the 38% volatile solids can't be met, redigest a sample aerobically in a lab under specified conditions. If the further reduction is less than 15% after 30 days, the standard has been met.
4. For aerobically digested sludge. demonstrate that the specific oxygen uptake rate (SOUR) is equal to or less than a specified rate under specified conditions.
5. Aerobically treat the sludge for at least 14 days under specified elevated temperatures (avg > 45 C; min > 40 C).
6. Raise pH to > 12 by lime addition. two hours and II. 5 after 24 hours. Without adding more lime, pH must remain at least 12 for
7. Stabilized sludge is dried to at least 75% solids.
8. Unstabilized sludge is dried to at least 90% solids.
9. Sludge is subsurface injected into the soil.
10. Incorporate sludge into soil within 6 hours of spreading.
11. Cover with soil by end of each day (this is for disposal in a sludge-only landfill).
12. For septage, add enough lime to raise pH to 12 for 3O minutes.

Any one of Options 1-10 above can be used for bulk sludge applied to farmland, forest, or reclamation site. Any one of Options 1-8 can be used when bulk sludge is applied on a lawn or home garden (this must be Class A sludge). Any one of Options 1-8 can be used for sludge products sold in a bag (must also be Class A). Any one of Options I - 11 can be used for surface disposal of sludge. Any one of Options 9, 10, or 12 can be used for land application of septage.


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EPA PART 503 RULE
MONITORING REQUIREMENTS
The following table shows the frequency of sludge monitoring for metals, for bacteria (if required), and for vector attraction reduction when the sludge is land applied:

Amount of Sludge* in Metric Tons per Year	Frequency
0 to 290	Once per year
290 to 1500	Once per quarter
1500 to 15,000	Once per 60 days
15,000 or more	Once per month

*Amount of sludge means either the amount of bulk sludge applied to land, or the amount of sludge received by a second treatment facility for Class A standards. such as a com posting or pelletizing facility.

For land applied sludge, metals must be tested.

For land applied sludge, bacteria must be tested to qualify for Class A standards.

For land applied sludge, bacteria must be tested to qualify for Class B standards only if the treatment method is not a PSRP or equivalent method.

For land applied sludge, if any of vector attraction reduction Options 1 - 8 are chosen, the sludge must be tested to ensure it meets the applicable requirements.


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EPA PART 503 RULE
RECORDKEEPING REQUIREMENTS FOR GENERATORS

1. Exceptional Quality (EQ) Sludge --
   
   If sludge meets Class A standards, the metal concentration limits in Table 3, and any one of vector attraction reduction Options 1-8, it is called EQ sludge. There are no site restrictions required for EQ sludge, and cumulative metal loading, rates do not need to be tracked, calculated, and updated. EQ sludge may be sold for use on home lawns and gardens. The recordkeeping requirements for EQ sludge are the following, and all are for 5 years:
   1. Keep sample results for metals.
   2. Keep a specified signed certification statement attesting that all applicable standards have been tested for and met.
   3. Keep a description of how Class A standards have been met.
   4. A description of how the vector attraction reduction standard has been met.
   
   
2. Class B, Table 3 Sludge --
   
   This is sludge that meets the most stringent metal limits (Table 3), but meets only Class B pathogen reduction requirements. The recordkeeping requirements are for five years, as follows:
   1. Keep sample results for metals.
   2. Keep certification statement.
   3. Keep description of how Class B standards are met.
   4. Keep description of how vector attraction standard is met.
   
   
3. Table 2 Sludge --
   
   This is sludge whose metal concentrations fall in between Table 3 (the EQ limits) and Table 1 (the ceiling concentrations). Cumulative metal loading rates need to be calculated, tracked, and updated to comply with the cumulative metal loading limits shown in Table 2. The following records must be kept for 5 years:
   1. Keep sample results for metals.
   2. Keep certification statement.
   3. Keep description of how Class A or Class B standards are met.
   4. Keep description of how vector attraction standard is met.
   
   
4. Table 4 Sludge --
   
   This is sludge that is sold in bags or containers, and therefore must meet Class A standards. However, unlike EQ sludge, the metal concentrations are higher than the Table 3 limits. Therefore the metal limits in Table 4 apply. The following records must be kept for 5 years:
   1. the annual application rate,
   2. metal sample results,
   3. certification, and
   4. description of how Class A and vectors are met.

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EPA PART 503 RULE
REPORTING REQUIREMENTS FOR GENERATORS

Who must report?

1. Class I sludge management facilities. These include all sewage treatment plants required to have pretreatment, as well as any plant so designated by the EPA Regional Administrator because of the potential for its sludge or disposal practices to cause problems.
   
2. Treatment plants with a design flow of at least 1 MGD.
3. Treatment plants that serve a population of 10,000 or more.

What must be reported?

1. All the information in the recordkeeping requirements for generators. In addition, when 90% or more of the cumulative metal loading limits have been reached on a site, additional information about the site must be reported.

Who do the reports go to?

The reports must be sent to the permitting authority. The permitting authority is either EPA or a State with an EPA-approved sludge management program.

How often must reports be submitted?
Annually.

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EPA PART 503 RULE
MARYLAND'S PLANS

Delegation -- No final decision has been made on whether to seek delegation of the 503 Rule from EPA. However, planning for this has occurred and is still in progress.

Advantages (from State's viewpoint) -- State would control entire program; no potential conflicts with EPA.

Advantages (from generator's viewpoint) -- Would have just one set of rules to comply with. not two. One less layer of bureaucracy to answer to.

Disadvantages (from State's viewpoint) -- Would have more tasks to perform, would need more staff. No funding available from EPA. Cuts being made in State budget.

If Maryland becomes delegated, how would the plan work?

• Maryland's sludge regs would have to be changed to be compatible with 503.
• Discharge permits would require compliance with 503 regs, or Maryland's sludge regs after they've been changed.
• State permits for each site would still be required (this is a requirement of Maryland law).
• Water Mgt Admin would enforce requirements at treatment plants, Waste Mgt Admin would enforce requirements at application sites. How do Maryland regs and 503 regs differ?
• COMAR and State law require a separate permit for each site where sludge goes, unless sludge is treated by PFRP. 503 requires one permit for each treatment plant, not for each site where sludge is used.
• COMAR emphasizes management at field sites where sludge is applied. 503 emphasizes management at the treatment plants.
• Most permits issued under COMAR go to land appliers. The 503 permits would go to sludge generators and treaters.
• COMAR's field requirements are much more detailed and complex than 503. 503 requires testing for additional metals.
• COMAR's metal limits are more stringent than 503's, except for lead.

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COMPARISON OF SLUDGE METAL LIMITS (dry weight) FOR LAND APPLICATION

Parameter	MD Class 1 Limit Present	MD Class 1 Limit Intended	503 EQ Limit Table 3	503 Ceiling Limit Table 1
Arsenic	None	41 ppm	41 ppm	75 ppm
Cadmium	25 ppm	21 ppm ?	39 ppm	85 ppm
Chromium*	None	None	None	None
Copper	1000 ppm	1500 ppm	1500 ppm	4300 ppm
Lead	1000 ppm	300 ppm	300 ppm	840 ppm
Mercury	10 ppm	17 ppm	17 ppm	57 ppm
Molybdenum*	None	75 ppm ?	None	75 ppm
Nickel	200 ppm	420 ppm	420 ppm	420 ppm
Selenium*	None	100 ppm ?	100 ppm	100 ppm
Zinc	2500 ppm	2800 ppm	2800 ppm	7500 ppm
PCB's	10 ppm	10 ppm ?	None	None

*The EPA 503 limits for Chromium and Molybdenum were legally challenged. EPA originally adopted an 18 ppm limit for Molybdenum in Table 3; however, this was changed to 75 ppm following the legal challenge. The Chromium limits were originally set at 3000 ppm for Table 1, 3000 ppm for Table 2, 1200 ppm for Table 3, and 150 ppm for Table 4. These were challenged in court as too restrictive and without scientific basis. The court ordered EPA to reconsider the Chromium limits. Upon reconsideration, EPA discarded all limits for Chromium in land-applied (but not incinerated) sludge, since there was no risk-based rationale for those limits in land-applied sludge. Limits for Selenium in Table 3 were changed from 36 ppm to 100 ppm after initial publication of the regulation.



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EPA PART 503 RULE
TELEPHONE NUMBERS FOR QUESTIONS

EPA Region 3, Ann Carkhuff	(215) 566-5735 or (215) 814-5735 after July 1, 1998
Water Environment Federation	(703) 684-2400 or 1-800-666-0206
For Maryland's plans:
MDE Waste Mgt Admin, A.Hussain-Alhija	(410)631-3375
MDE Water Mgt Admin, Jeffrey Rein	(410) 631-3737

REFERENCES

40 CFR Part 503

"A Plain English Guide to the EPA Part 503 Biosolids Rule"
Published by EPA

"Land Application of Sewage Sludge -- A Guide for Land Appliers on the Requirements of the Federal Standards for the Use or Disposal of Sewage Sludge, 40 CFR Part 503"
Published by EPA

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