Land Application

Land application is the spreading or spraying of biosolids onto the surface of the land or the injection of biosolids beneath the surface of the land to condition the soil or to fertilize crops grown in the soil. Land application has been practiced for decades and continues to be the most common method of using biosolids.

Biosolids that meet certain requirements are commonly referred to as being of exceptional quality. Although the phrase is not found in Part 503, exceptional quality (EQ) biosolids are biosolids or materials derived from biosolids that meet Part 503 requirements of the pollutant ceiling concentrations, one of the class A pathogen reduction alternatives and one of the vector attraction reduction alternatives. If a generator or other preparer is able to demonstrate that biosolids or material derived from biosolids meet the criteria of EQ biosolids, the biosolids are not subject to the general requirements and management practices in the land application subpart of Part 503.

General Requirements The application of biosolids to the land may involve several parties. Although not all of these parties need to receive a permit, all of them must comply with the appropriate land application subpart requirements. The first general requirement for the applier of bulk biosolids is that no person may apply biosolids to the land without meeting the requirements in Subpart B of Part 503. These requirements include, but are not limited to, management practices, certain vector attraction reduction options, and the class B site restrictions. The land applier should request information from the preparer of biosolids to ensure that treatment-related requirements have been met. This includes pollutant concentrations in biosolids, the class of pathogen reduction, and whether vector attraction reduction is achieved through treatment. The person who applies biosolids to the land must also provide the owner or leaseholder of the land on which the biosolids are applied notice and necessary information to comply with the land application requirements. Requirements that may apply to the owner or leaseholder of the land include the site restrictions for class B biosolids, such as prohibitions on harvesting certain types of crops, grazing animals for certain periods, and restricting public access for certain periods.

Pollutant Limits The first of three parameters that must be assessed to determine the overall quality of biosolids is the level of pollutants. To allow land application of biosolids of variable quality, Part 503 provides four sets of pollutant limits: pollutant ceiling concentration limits, pollutant concentration limits, cumulative pollutant loading rates, and annual pollutant loading rates. These pollutant limits are listed in Table 1.1.

Ceiling Concentration Limits All biosolids that are land applied, and both bulk biosolids and biosolids sold or given away in a bag or other container, have to meet the ceiling concentration limits. These limits are absolute values, which means that all samples of biosolids have to meet the limits.

Pollutant Concentration Limits Biosolids meeting the pollutant concentration limits (also known as exceptional quality pollutant concentration limits)

TABLE 1.1 Land Application Pollutant Limits

Pollutant

Ceiling Concentration Limits2' (mg/kg)

Pollutant Concentration

Limitsacd (mg/kg)

Cumulative Pollutant Loading Rates (kg/ha)

Annual Pollutant Loading Rates (kg/ha/365-day period)

Arsenic

75

41

41

2.0

Cadmium

85

39

39

1.9

Copper

4300

1500

1500

75

Lead

840

300

300

15

Mercury

57

17

17

0.85

Molybdenum

75

Nickel

420

420

420

21

Selenium

100

36

100

5

Zinc

7500

2800

2800

140

Applies to:

All biosolids

Bulk biosolids

Bulk biosolids

Biosolids sold

that are land

and biosolids

orgiven away in

applied

sold or given

a bag or other

away in a bag

container

or other

container

Source: U.S. EPA, 1994. a Dry weight basis. b Absolute values. c Monthly averages. d Exceptional quality biosolids.

Source: U.S. EPA, 1994. a Dry weight basis. b Absolute values. c Monthly averages. d Exceptional quality biosolids.

achieve one of three levels of quality necessary for exceptional quality status, hence can be sold or given away in bags or other containers. These limits must also be met when bulk biosolids are land applied. The limits are monthly averages (i.e., the arithmetic average of all measurements taken during the month).

Cumulative Pollutant Loading Rates The cumulative pollutant loading rates apply to bulk biosolids that meet ceiling concentration limits but do not meet pollutant concentration limits. These rates limit the amount of a pollutant that can be applied to an area of land in bulk biosolids for the life of the application site.

Annual Pollutant Loading Rates The annual pollutant loading rates apply to biosolids that meet ceiling concentration limits but do not meet pollutant concentration limits, and are to be sold or given away in a bag or other container for application to the land. Annual pollutant loading rates rather than cumulative pollutant loading rates are applied to these biosolids because biosolids sold or given away in a bag or other container are commonly used by homeowners, and it would be impractical to expect homeowners to track cumulative pollutant loadings. Design application rates of biosolids for land application based on nitrogen and pollutant concentration are described in Chapter 10.

Pathogen Reduction The second parameter in determining biosolids quality is the presence or absence of pathogens. Pathogens are disease-causing organisms such as Salmonella bacteria, enteric viruses, and viable helminth ova. The preparer of biosolids is responsible for monitoring and certifying that measures have been taken to reduce these types of pathogens in the biosolids they produce.

Part 503 contains two classes of pathogen reduction: classes A and B. Class A pathogen reduction alternatives render the biosolids virtually pathogen-free after treatment. Class B pathogen reduction alternatives reduce pathogens significantly. Land appliers who apply biosolids that are certified as class A have no restrictions relative to pathogens. Land application of class B bio-solids comes with it the following site restrictions, which are necessary to provide the same level of protection to public health and the environment as is provided by class A biosolids:

• Public access to land with a high potential for public exposure shall be restricted for one year after biosolids application.

• Public access to land with a low potential for public exposure shall be restricted for 30 days after biosolids application.

• Food crops, feed crops, or fiber crops shall not be harvested for 30 days after biosolids are applied.

• Food crops with harvested parts that touch the biosolids-soil mixture and are totally above the land surface (e.g., melons, cucumbers, squash) shall not be harvested for 14 months after application of biosolids.

• Food crops with harvested parts below the surface of the land (e.g., potatoes, carrots, radishes) shall not be harvested for 20 months after application when biosolids are not incorporated into the soil or remain on the soil surface for four or more months prior to incorporation into the soil.

• Food crops with harvested parts below the surface of the land (e.g., potatoes, carrots, radishes) shall not be harvested for 38 months if biosolids are incorporated into the soil within four months after application.

• Animals shall not be grazed on the site for 30 days after biosolids application.

• Turf shall not be harvested for one year after biosolids application if the turf is placed on land with a high potential for public exposure, or on a lawn, unless otherwise specified by the permitting authority.

Vector Attraction Reduction Attractiveness of biosolids to vectors is the third parameter of biosolids quality. Vectors are animals and insects, such as rodents, flies, and birds, that might be attracted to biosolids and therefore could transmit pathogenic organisms to humans or to domestic animals or livestock. One of the 10 options provided in Subpart D of Part 503 to reduce vector attractiveness must be met if biosolids are to be applied to the land. The 10 vector attraction reduction options, which are discussed in more detail at the end of this chapter, fall into two categories: treatment options (options 1 through 8) and barrier options (options 9 and 10). Treatment options are undertaken by the biosolids preparer. If any one of the treatment options is performed by the preparer, the land applier has no requirements relative to vector attraction reduction. If one of the treatment options is not performed by the preparer, the land applier is responsible for implementing and certifying compliance with either one of the barrier options, which use soil as a barrier between the biosolids and any vectors that might be present.

Management Practices Four management practices are specified for bulk biosolids that are applied to the land. The practices help ensure that biosolids are applied in a manner that is protective to human health and environment. The four management practices applicable to the land application of bulk nonexceptional quality biosolids are:

• Endangered species or critical habitat protection

• Application to flooded, frozen, or snow-covered land

• Distance to surface waters

• Agronomic application rate

Endangered Species or Critical Habitat Protection Application of bulk non-EQ biosolids is prohibited if it is likely to affect threatened or endangered species or their designated critical habitat. Any direct or indirect action that reduces the likelihood of survival and recovery of a threatened or endangered species is considered an adverse effect. Critical habitat is any place where a threatened or endangered species lives and grows during any stage of its life cycle. The U.S. Department of Interior, Fish and Wildlife Service (FWS) publishes a list of threatened or endangered species. To comply with this management practice, the land applier should consult with FWS to determine whether any threatened or endangered species or their designated critical habitats are present at the site.

Application to Flooded, Frozen, or Snow-Covered Land Part 503 does not prohibit the application of bulk non-EQ biosolids to flooded, frozen, or snow-covered land. It does allow that the permitting authority can withhold this permission. Part 503 does state that biosolids applied to these lands may not enter wetlands or other waters of the United States. Prior to applying biosol-ids to these lands, the land applier should ensure that proper runoff control measures, such as slope restrictions, berms, dikes, silt fences, and sediment basins, are in place.

Distance to Surface Waters Application of bulk non-EQ biosolids on agricultural land, forest, or a reclamation site that is within 10 m of any waters of the United States is prohibited unless otherwise specified by the permitting authority. The 10-m buffer zone serves as a barrier against biosolids entering water bodies.

Agronomic Application Rate Bulk non-EQ biosolids should be applied to a site only at a rate equal to or less than the agronomic rate for the site. The agronomic rate is the application rate that is designed to provide the amount of nitrogen needed by the crop or vegetation and thus to minimize the amount of nitrogen that passes to the groundwater and contaminates it. In some instances, the permitting authority may specifically authorize application to a reclamation site at a rate in excess of the agronomic rate, where there is no potential for nitrate to leach down to the groundwater. However, once a vegetation cover has been established, future application of biosolids should be limited to the agronomic rate of the vegetation grown.

Only one management practice applies to biosolids sold or given away in a bag or other container. A label or information sheet must be provided with the biosolids indicating the appropriate application rate for the quality of the biosolids.

Monitoring The person who prepares biosolids must monitor biosolids quality. As mentioned earlier, the land applier must obtain information from the preparer on the pollutant concentrations in the bulk non-EQ biosolids.

TABLE 1.2 Parameters To Be Monitored in Land-Applied Biosolids

Pollutants2 Pathogens

Vector Attraction Reduction

Arsenic Fecal coliform or Salmonella

Percent volatile solids reduction

Cadmium Enteric virusesb

Specific oxygen uptake rated

Copper Helminth ovab

pHe

Lead

Percent solidsf

Mercury

Molybdenum

Nickel

Selenium

Zinc

a Dry weight basis.

b Class options 3 and 4.

c Vector attraction reduction options 1, 2, and 3.

d Vection attraction reduction option 4.

e Vection attraction reduction option 6.

f Vector attraction reduction options 7 and 8.

TABLE 1.3 Monitoring Frequency for Land Application

Biosolids Quantity2

(dry metric tons/365-day period)

Frequencyb

0 to <290

Once per year

290 to <1500

Once per quarter (4 times/year)

1500 to <15,000

Once per 60 days (6 times/year)

15,000 or greater

Once per month (12 times/year)

a Bulk biosolids or biosolids sold or given away in a bag or other container. b After two years the permiting authority may reduce the frequency for pollutant concentrations and for the pathogen density rerquirements.

a Bulk biosolids or biosolids sold or given away in a bag or other container. b After two years the permiting authority may reduce the frequency for pollutant concentrations and for the pathogen density rerquirements.

Parameters that must be monitored are listed in Table 1.2. The frequency of monitoring is typically established by the permitting authority through individual permits on a case-by-case basis. However, to enhance the self-implementation of the regulation, Part 503 has established the monitoring frequency shown in Table 1.3.

Record Keeping Records must be kept to show compliance with pollutant concentration and loadings, pathogen reduction requirements, and management practices. These requirements are divided into responsibilities for the biosolids preparer and for the land applier. All preparers must keep records of biosolids quality regardless of whether the biosolids are EQ or non-EQ.

Record-keeping requirements for land appliers vary depending on biosol-ids quality. However, all appliers of bulk non-EQ biosolids must document implementation of applicable management practices. The land applier must also keep records tracking the cumulative pollutant loadings. When the site reaches 90% of its allowable cumulative pollutant loading, the land applier should notify the preparer annually until the site reaches 100%, and then no additional biosolids that are non-EQ for pollutants can be applied. When the bulk biosolids are non-EQ for pathogens, the applier must keep records on the implementation of class B site restrictions. When the bulk biosolids are non-EQ for vector attraction reduction, the applier must keep records documenting the implementation of the vector attraction reduction options 9 and 10 (discussed later in this chapter). Unless otherwise noted by the permitting authority, records must be kept for a minimum of five years.

Reporting Reporting requirements apply to wastewater treatment plants with a design flow of 4000 m3/day (1 mgd) and to plants with a service population of 10,000 people or more. Reporting requirements also apply to class I sludge management facilities, which are treatment plants that are required to have an approved pretreatment program.

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