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United States Environmental Protection Agency 
Determination of Class A Biosolid.

Alternatives for Meeting Class "A" Pathogen Requirements

Alternative 1: Thermally treated biosolids
Biosolids must be subject to one of the following four (4) time-temperature regimes:

• 7 percent solid or greater biosolids must be heated to 50 degrees Celsius of higher for 20 minutes or longer.
• 7 percent solid or greater biosolids in the form of small particles and heated by contact with either warmed gases or immiscible liquid must be heated to 50 degrees Celsius or higher for 15 seconds or longer.
• Biosolids less than 7 percent solid must be heated for at least 15 seconds but less than 30 minutes using the following equation:

D=131,700,000/10^{0.14 t}

• Biosolids less than 7 percent solid must be heated to 50 degrees Celsius of higher with at least 30 minutes of longer contact time.

Alternative 2: Biosolids treated in a high pH-high temperature process
Biosolids must meet specific pH, temperature, and air-drying requirements.

• Biosolid pH must be elevated greater than 12 (measured a 25 degrees Celsius) for 72 hours or longer
• Biosolids temperature must be maintained above 52 degrees Celsius for at least 12 hours during the period that the pH is greater than 12
• Biosolids must be air dried to over 50 percent solids after the 72 hour period of elevated pH
• All pathogen requirements must be met.

Alternative 3: Biosolids treated in other known processes
The alternative mandates comprehensive monitoring of the biosolids for enteric viruses and viable helminth ova until the process has shown adequate reduction of pathogens. Enteric viruses must have been shown to be present prior to treatment to show the effectiveness of the treatment process. Test requirements include:

• Having been shown to be present before treatment, less than one plaque forming unit per 4 grams of total solids (by dry weight) in treated biosolids be present.
• Helminth ova must also be less than 1 unit per 4 grams of dry biosolid.
  All pathogen requirements must be met.

Alternative 4: Biosolids treated in other unknown processes
This alternative is used when:

• A biosolids treatment process is unknown, or
• the biosolids were treated in a process with less stringent requirements than are called for in a Class "A" alternative,
• All pathogen requirements must be met.

Alternative 5: Biosolids treated in a PFRP
Biosolids are considered Class A if they are treated in one of the following ways:

Composting.   In-vessel or aerated pile composting must maintain biosolids at 55 degrees Celsius or higher for 3 days, or windrow compost biosolids must maintain 55 degrees Celsius for 20 days or longer and must be turned at least 5 times.

• Heat Drying.   Biosolids are heated with hot gases to raise percent solids to 90 percent or higher. Temperatures must exceed 80 degrees Celsius.
• Heat Treatment.   Liquid biosolids are heated above 180 degrees Celsius for 30 minutes.
• Thermophilic Aerobic Digestion.   Aerobic conditions must be maintained while the holding time of 10 days is maintained at 55-60 degrees Celsius.
• Beta Ray Irradiation.   Beta rays are used from an accelerator at a minimum of 1.0 megarad at 20 degrees Celsius.
• Gamma Ray Irradiation.   Certain isotopes gamma rays at 20 degrees Celsius used for irradiation.
• Pasteurization.   Biosolids are maintained at 70 degrees Celsius or above for 30 minutes or longer.

Alternative 6: Biosolids Treated in a Process Equivalent to a PFRP
If biosolids are treated in a process determined to be equivalent to a PFRP process by the authority issuing permits, and meets all pathogen requirements

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PATHOGEN REQUIREMENTS FOR ALL CLASS "A" ALTERNATIVES

• Fecal coliform densities must be less than 1,000 most probable number (MPN) per gram of total dry solids, or
• Salmonella sp. bacteria must be less than 3 MPN per 4 grams of total dry solids.
• Either of these requirements must be met at one of the following times.
  when biosolids are used or disposed;
• when the biosolids are prepared for sale or give-away in a bag or other container for land application; or
• when the biosolids or derived materials are prepared to meet the requirements for EQ biosolids.

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Alternatives for Meeting Class "B" Pathogen Requirements

Alternative 1: Monitoring Indicator Organisms
Testing for fecal coliforms is used as an indicator for all pathogens and is done prior to the biosolids use or disposal. Less than 2 million Most Probable number (MPN) OR

Colony Forming Units (CFU) per gram of dry biosolid is required to qualify as a Class B biosolid. EPA suggest that seven test samples be taken over a 2 week period because the testing procedures lack precision and the biosolids lack uniformity. Multiple samples should ensure a representable sampling of the biosolids.

Alternative 2: Biosolids Treated with a PSRP
Biosolids must be treated by one of the five (5) Processes to Significantly Reduce Pathogens (PSRP).

• Aerobic Digestion. Biosolids are kept under aerobic conditions for a specific time ranging between 40 days at 20 degrees Celsius and 60 days at 15 degrees Celsius.
• Air Drying. Biosolids are air dried on pads (sand or paved) for a minimum of 3 months, with at least 2 of the months having an ambient average daily temperature above 0 degrees Celsius.
• Anaerobic Digestion. Biosolids are kept under anaerobic conditions for a specified time and under a specific temperature ranging between 15 days at 35-55 degrees Celsius and 60 days at 20 degrees Celsius.
• Composting. Using any of three methods of composting (in-vessel, static aerated pile, or windrowed), the temperature is raised to 40 degrees Celsius or higher and maintained for 5 days, 4 hours of which, the temperature of the pile must rise above 55 degrees Celsius.
• Lime Stabilization. Enough lime is added to the biosolids to raise the pH of the biosolids to 12 after 2 hours of contact.

Alternative 3: Biosolids Treated in a Process Equivalent to a PSRP
The biosolids must be treated in a process equal to a PSRP as determined by the permitting authority. Authority is given to the permitting authority by the EPA to determine what is "equivalent."

 

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Site Restrictions for Land Applied Class B Biosolids

Crops that Touch Biosolids
Food crops that have harvested parts that touch the mixture of soil and biosolids and are totally above the soil surface, cannot be harvested for 14 months after biosolid application.

Crops Embedded in the Soil
Food crops that have harvested parts growing in the soil where biosolids were applied and left on the surface for 4 months or longer before being incorporated into the soil, cannot be harvested for 20 months after biosolid application.

Food crops that have harvested parts growing in the soil where biosolids were applied and left on the surface less than 4 months before being incorporated into the soil, cannot be harvested for 38 months after biosolid application.

Feed Crops, Fiber Crops, and Food Crops that Do Not Touch the Soil
Food crops that do not touch the soil/biosolids mixture, feed and fiber crops cannot be harvested for 39 days after biosolid application.

Animal Grazing
Animals cannot graze on land treated with biosolids for at least 30 days after application of biosolids.

Turf Growing
Unless specified by the permitting authority, turf grown with a biosolids treatment cannot be harvested for 1 year after biosolid application when being use on a lawn or other area with a high potential for public access.

Public Access
Public access to land with a high potential for expose to the public is restricted for 1 year from the application of biosolids.

Public access to land with a low potential for expose to the public is restricted for 30 days from the application of biosolids.

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Land Application Management Practice Requirements

For EQ Biosolids
There are no restrictions. (Unless established by EPA or the State permitting authority on a case-by-case basis for bulk biosolids to protect public health and the environment.)

For PC and CPLR Biosolids
These types of biosolids cannot be applied to flooded, frozen, or snow-covered agricultural land, forests, public contact sites, or reclamation sites in such a way that the biosolids enter a wetland or other waters of the United States (as defined in 40 CFR Part 122.2, which generally includes tidal waters, interstate and intrastate waters, tributaries, the territorial sea, and wetlands adjacent to these waters), except as provided in a permit issued pursuant top Section 402 (NPDES Permit) or Section 404 (Dredge and Fill Permit) of the Clean Water Act, as amended.

These types of biosolids cannot be applied to agricultural land, forests, or reclamation sites that are 10 meters or less from U.S. waters, unless otherwise specified by the permitting authority.

If applied to agricultural land, forests, or public contact sites, these types of biosolids must be applied at a rate that is equal to or less than the agronomic rate for nitrogen for the crop to be grown. Biosolids applied to reclamation sites may exceed the agronomic rate for nitrogen as specified by the permitting authority.

These types of biosolids must not harm or contribute to the harm of a threatened or endangered species or result in the destruction or adverse modification of the species' critical habitat when applied to the land. Threatened or endangered species and their critical habitats are listed in Section 4 of the Endangered Species Act. Critical habitat is defined as any place where a threatened or endangered species lives and grows during any stage of its life cycle. Any direct of indirect action (or result of any direct or indirect action) in a critical habitat that diminishes the likelihood of survival and recovery of a listed species is considered destruction or adverse modification of a critical habitat.

For APLR Biosolids
A label must be affixed to the bag or other container, or an information sheet must be provided to the person who receives APLR biosolids in other containers. At a minimum, the label or information sheet must contain the following information:

• the name and address of the person who prepares the biosolids for sale or give-a-way in a bag or other container;
• a statement that prohibits application of the biosolids to the land except in accordance with the instructions on the label or information sheet.
• an Annual Whole Sludge (biosolids) Application Rate (see Part 503 for more information) that does not cause the APLRs to be exceeded, and;
  the nitrogen content.

There is NO federal labeling requirements for EQ biosolids sold or given away in a bag or other container.

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General Requirements for the Land Application of Biosolids

For EQ Biosolids

None (unless set by EPA or State permitting authority on a case-by-case basis for bulk biosolids to protect public health and the environment.)

For PC and CPLR Biosolids

The preparer* must notify and provide information necessary to comply with the Part 503 land application requirements to the person who applies bulk biosolids to the land.

The preparer who provides biosolids to another person who further prepares the biosolids for application to the land must provide this person with notification and information necessary to comply with the Part 503 land application requirements.

The preparer must provide written notification of the total nitrogen concentration (as N on a dry-weight basis) in bulk biosolids to the applier of the biosolids to agricultural land, forests, public contact sites, or reclamation sites.

The applier of biosolids must obtain information necessary to comply with the Part 503 land application requirements, apply biosolids to the land in accordance with the Part 503 land application requirements, and provide notice and necessary information to the owner or leaseholder of the land on which biosolids are applied.

Out of State Use

The preparer must provide written notification (prior to the initial application of the bulk biosolids by the applier) to the permitting authority in the State where biosolids are proposed to be land applied when bulk biosolids are generated in one State and transferred to another State for application to the land. The notification must include:

·         the location (either street address of latitude and longitude) of each land application site;

·         the approximate time period the bulk biosolids will be applied to the site;

·         the name, address, telephone number, and National Pollutant Discharge Elimination System (NPDES) permit number for both the preparer and the applier of the bulk biosolids; and

·         additional information or permits in both States, if required by the permitting authority.

Additional Requirements for CPLR Biosolids

The preparer must notify the permitting authority in the State where bulk biosolids are to be applied prior to the initial application of the biosolids. This is a one-time notice requirement for each land application site each time there is a new supplier. The notice must include:

·         the location (either street address of latitude and longitude) of the land application site; and

·         the name, address, telephone number, and NPDES permit number (if appropriate) of the person who will apply the bulk biosolids.

The applier must obtain records (if available) from the previous applier, landowner, or permitting authority that indicate the amount of each CPLR pollutant in biosolids that have been applied to the site since July 20, 1993. In addition:

·         when these records are available, the applier must use this information to determine that additional amount of each pollutant that can be applied to the site in accordance with the CPLRs in Table 2;

·         the applier must keep the previous records and also record the additional amount of each pollutant he or she is applying to the site; and

·         when records of past known CPLR applications since July 20, 1993, are not available, biosolids meeting CPLRs cannot be applied to that site. However, EQ or PC biosolids could be applied.

If biosolids meeting CPLRs have not been applied to the site in excess of the limit since July 20, 1993, the CPLR limit for each pollutant in Table 2 will determine the maximum amount of pollutant that can be applied in biosolids if:

·         all applicable management practices are followed; and

·         the applier keeps a record of the amount of each pollutant in biosolids applied to any given site.

The applier must not apply additional biosolids under the cumulative pollutant-loading concept to a site where any of the CPLRs have been reached.

 

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SOURCE: A Plain English Guide to the EPA Part 503 Biosolids Rule.

Title 40 of the Code of Federal Regulation, Part 503

 

HOW BIOSOLIDS ARE REGULATED

Effective on March 22, 1993, 40 CFR Part 503 initiated regulation on the use or disposal of sewage sludge, or biosolids. This regulation was developed to protect public health and the environment from any reasonably anticipated adverse effects of certain pollutants that might be present in sewage biosolids.

The regulations outline a hierarchy of different residuals based on how the residual solids are handled and processed at the treatment facility and/or at subsequent processing facilities. The three main points of Part 503 are pathogen kill, specific metals concentrations, and vector attraction reduction. For the purpose this document, biosolids will be broken up into two categories: Exceptional Quality and Non-Exceptional Quality. Common processes of each type are listed in Table 1.

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TABLE 1:

Common Processes by Category of Product

Exceptional Quality	Non-Exceptional Quality
(Class A Disinfection)	(Class A or B Disinfection)
N-Viro Soil Composting Pelletization Lime Sterilization	Anaerobic Digested Aerobic Digested Lime Treatment Zimpro

 

Pathogen Reduction/Destruction

Part 503 differentiates between Class A and Class B disinfection of sewage sludge, with Class A being far superior (2000 times more stringent) to Class B in its pathogen destruction. Class A technologies have shown that they reduce pathogens below detectable levels. Alternatives for Class A disinfection can be found at Class A Pathogen Kill Alternatives. EQ biosolids are not governed by additional regulations.

Some Class A and all Class B processes must adhere to strict management practices and in addition to the general requirements. For example, in the case of Class B biosolids food crops with harvested parts below the surface of the land can not be harvested for 36 months, and public access to land with a high potential for public exposure is restricted for 1 year after application of Class B biosolids. These additional restrictions on Class B biosolids are meant to protect human health and the environment from the increased levels of pathogens found in Class B material compared to Class A pathogen disinfection levels. There is no level of disinfection required for biosolids that are land filled, putting workers at greater risk.

Regulated Metals Concentrations

There are ten heavy metals concentrations that are regulated in Part 503. These metals must meet different concentration requirements in order to be classified to a specific category of biosolid (EQ, PC, or CPLR). Refer to Table 2 below for a full listing of the different required levels for each classification (Tables 1-3 of Part 503). The lowest levels of metals concentrations are required for Exceptional Quality biosolids, but only ceiling limits must be met by Non-EQ biosolids that meet at least Class B disinfection. These concentration levels were arrived at only after a 10 year risk assessment by scientists with USEPA and USDA using the most limiting pathway, ingestion by a small child, and demonstrate undeniable, scientific evidence of acceptable levels. Concentrations levels for disposal options include only Arsenic, Cadmium and Nickel, and are based on the distance between the active biosolids unit boundary and the property line of the surface disposal site.

TABLE 2:

Pollutant Limits

*Bagged biosolids are sold or given away in bags or other containers.
Molybdenum concentrations are currently being reconsidered by USEPA
Source: A Plain English Guide to the EPA Part 503 Biosolids Rule.

The Part 503 rule relies heavily on the fact that it is a self implementing rule. Enforcement of Part 503 can be an uphill battle due to the resources necessary to deal with such a wide ranging rule affecting everyone from municipalities to individual farmers.

The degree to which vectors, such as flies and rodents, are attracted to biosolids is referred to as a biosolids vector attraction. Methods to reduce vector attraction are outlined and defined in Part 503 and can be found in Table 3 below. Part 503 never directly addresses the odor or stability of a biosolid because it was viewed as subjective during the writing of the rule. Vector attraction reduction (VAR) is an attempt by EPA to address stability. Exceptional Quality biosolids must satisfy one of the first eight methods for vector attraction reduction (Table 3), whereas Non-Exceptional Quality biosolids are required to meet any one reduction in vector attraction. Biosolids that are disposed of in a landfill are not required to meet any method of VAR.

TABLE 3:
Ways to Accomplish Vector Attraction Reduction

*Option 1: Meet 38% reduction in volatile solids content.
Option 2: Demonstrate VAR with additional anaerobic digestion in a bench-scale unit.
Option 3: Demonstrate VAR with additional aerobic digestion in a bench-scale unit.
Option 4: Meet specific oxygen uptake rate for aerobically digested biosolids.
Option 5: Use aerobic processes at greater than 40 degrees C for 14 days or longer.
*Option 6: Alkali addition under specific conditions.
Option 7: Dry biosolids with no unstabilized solids to at least 75% solids.
Option 8: Dry biosolids with unstabilized solids to at least 90% solids.

Option 9: Inject biosolids beneath the soil surface.
Option 10: Incorporate biosolids into the soil within 6 hours of application to or placement on the land.
Option 11: Cover biosolids placed on a surface disposal site with soil or other material at the end of each operating day. (Note: Only for surface disposal.)
Option 12: Alkaline treatment of domestic septage to pH 12 or above for 30 minutes without adding more alkaline material.

NOTE: One of the first eight options must be met in order to qualify as Exceptional Quality (EQ).

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