National Academies Press: OpenBook

Biosolids Applied to Land: Advancing Standards and Practices (2002)

Chapter: 2 Biosolids Management

« Previous: 1 Introduction
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

2
Biosolids Management

Wastewater treatment necessarily produces two end products: effluent and sewage sludge. All wastewater generated in homes, businesses, industries, and other venues that is conveyed to wastewater treatment plants is treated to allow effluent discharge back into the surface and groundwaters of the United States. Sewage sludge is likewise treated in the wastewater process, generally through aerobic or anaerobic microbial activity for specified time periods and temperatures. Both effluent and sewage sludge require treatment to ensure that their release into the environment is protective of human health and the environment as required by the Clean Water Act (CWA). Sewage sludge is defined as the solid, semi-solid, or liquid residue generated during the treatment of domestic sewage in a treatment works, and biosolids are defined in this report as sewage sludge that has been treated to meet standards for land application under Part 503 of the CWA or any other equivalent land-application standards.

Of the nation’s estimated 263 million people in 1996, 190 million of them or 72% contributed wastewater directly through a sewerage system to approximately 16,000 publicly owned treatment works (POTW) (EPA 2000a). The remaining 73 million people discharged wastewater to some form of on-site treatment system or holding tank, more than half of which also is ultimately discharged to a POTW (Razvi 2000). Each person discharging human waste to a wastewater treatment system produces approximately 47 dry pounds (21 kilograms) of sewage sludge each year (EPA 1993). As the population of the

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

United States increases, the percentage of the population directly discharging to POTWs is projected to increase to 88% by 2016 (EPA 2000a). The ability to effectively treat and return wastewater and sewage sludge to the environment in a protective manner is of paramount importance from both a public-health and an environmental perspective. In partial recognition of this fact, Congress passed the CWA of 1972 and the federal government has contributed $61.1 billion in grants and $16.1 billion in low-interest loans to municipal and local governments between 1972 and 1999 for capital construction costs to provide necessary support for wastewater and sewage-sludge treatment and disposition of biosolids (EPA 2000a). Approximately 40% of that amount has been used for sewage sludge treatment and disposition of biosolids (Peavy et al. 1985). Sewage sludge is generated in several treatment processes that generally include primary (from primary clarification) and secondary (from secondary clarification) sewage sludge. The general process of treating wastewater and sewage sludge is illustrated in Figures 2–1 and 2–2.

EPA is responsible under Section 405 of the CWA to promulgate regulations for sewage sludge use or disposal. The CWA Amendments of 1987 added special provisions that required EPA to identify toxic pollutants and set sewage-sludge standards that are “adequate to protect public health and the environment from any reasonably anticipated adverse effect of each pollutant” (emphasis added). Recognizing that sewage-sludge production will continue to increase and that sewage sludge possesses many potential beneficial properties for agricultural production, federal and state agencies have long advocated the recycling of it as biosolids through land application (EPA 1981, 1984, 1991). The other primary options for sewage sludge disposition are to bury it in a landfill or to incinerate it. Although these latter options possess inherent risks and environmental difficulties, these options are beyond the scope of this report (see Chapter 1).

Of the 16,000 POTWs in the United States, approximately 8,650 generate sewage sludge that must be used or disposed of at least annually (Wisconsin Department of Natural Resources, unpublished data, 2001). Based on data from 37 states, approximately 5,900 of these sewage sludge generators (68%) either land apply or publicly distribute over 3.4 million dry tons of biosolids each year (see also End Use Practice section of this chapter). Most of this recycling use is conducted without public opposition and with no documented adverse health effects. However, recent allegations of adverse health effects have received media and congressional attention. Chapter 3 assesses the epidemiological evidence and approach for health effects associated with biosolids production and application, but does not systematically investigate these allegations. Rather, the report examines the process by which the regulations were established and determines whether advances in risk-assessment methods warrant a revisiting of the process.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

FIGURE 2–1 The process schematic delineating water and wastewater treatment along with the sewage sludge stream.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

FIGURE 2–2 Sewage sludge treatment alternatives.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

This chapter briefly examines the development of the Part 503 rule, certain related issues, and what EPA has done to implement the rule since promulgation. It also reviews how states implement the rule, whether or not they have explicit delegated authority from EPA. An examination of biosolids regulations and practices in Europe is then used to compare and contrast these practices. An overview of the acceptable pathogen treatment controls and land application site restrictions, is presented, as well as associated methods for stabilization to reduce the attraction to vectors, such as rodents. Issues are raised that relate to the verification of the efficacy of treatment. Finally, this chapter examines end-use practices in the United States, biosolids quality achieved, data on nonregulated pollutants, risk-management practices inherent to land application of biosolids (primarily Class B) and to the risk-assessment process, and compliance and enforcement strategies and action taken by EPA or states.

FEDERAL BIOSOLIDS REGULATIONS AND CURRENT STATE OF PROGRAM

History

The current biosolids standards became effective in Part 503 of Chapter 40 of the Code of Federal Regulations (40 CFR 503) on March 22, 1993 (EPA 1993). More specifically, the regulations are established as General Requirements, Pollutant Limits, Management Practices, Operational Standards, Frequency of Monitoring Requirements, Record Keeping, and Reporting. The requirements apply to each of the three major methods of ultimate disposition of sewage sludge or biosolids: recycling and public distribution, burial in a municipal solid-waste landfill or a surface disposal site, or incineration. Enforceable standards are established for all three options, but this report focuses only on land application and public distribution. The standards were developed over more than 10 years and received both public and private input. From September 13, 1979, until 40 CFR 503 was published, standards for the land application of biosolids were set in 40 CFR Part 257 (EPA 1979). Research focusing on the beneficial micro- and macronutrients present in treated sewage sludge had been conducted at numerous universities before the publication of the 1979 regulations (e.g., Keeney et al. 1975). Indeed, Wisconsin statutes specifically encouraged the responsible recycling of biosolids through use on agricultural land beginning in 1973 (Wisconsin Statutes Assembly Bill 128, 1973).

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Because POTWs typically have industrial contributors to their wastewater collection systems, wastewater pretreatment regulations became effective through 40 CFR Part 403 on June 26, 1978, with a stated objective to

  1. prevent the introduction of pollutants into POTWs which will interfere with the operation of a POTW, including interference with its use or disposal of municipal biosolids;

  2. prevent the introduction of pollutants into POTWs which will pass through the treatment works or otherwise be incompatible with such works; and

  3. improve opportunities to recycle and reclaim municipal and industrial wastewaters and biosolids (EPA 1999a).

These regulations to control pollution dramatically reduced the concentrations of selected pollutants discharged to applicable sewerage systems and therefore also the concentrations in the resultant biosolids (see also Characterization of Biosolids section).

Federal Policy

EPA has had a long-standing policy of promoting the beneficial use of biosolids, and a regulatory mandate to review and revise related regulations periodically as new research warrants. In January 1981, EPA published a statement of federal policy and guidance with the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) for the proper management and necessary controls of land application of biosolids for the production of fruits and vegetables. EPA (1984) further formalized its policy of promoting beneficial use and developing a comprehensive regulatory approach as mandated by the CWA in the Federal Register on June 12, 1984. EPA again clarified that position through the publication of an interagency policy, which with six other federal agencies promoted the beneficial use of biosolids in the Federal Register on July 18, 1991 (EPA 1991).

Section 402 of the CWA sets provisions for permitting discharges, including sewage sludge, to waters of the United States. As authorized by the CWA, the National Pollutant Discharge Elimination System (NPDES) permit program has been in place since 1972 and regulates point sources of water pollution, such as pollutants discharged from pipes or ditches. Many states consider the land application of biosolids to be a point-source discharge to groundwater and regulate this practice under the permit program. Individual homes that are connected to a municipal system, use a septic system, or do not

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

have a surface discharge do not need an NPDES permit; however, industrial, municipal, and other facilities must obtain permits if their discharges go directly to surface waters. In most cases, the NPDES permit program is administered by authorized states. Chapter 40 of CFR 501 was published in 1989 to set a regulatory framework for states seeking delegated authority to implement a biosolids program under permits in compliance with Section 402. At present, there are five states that have received delegation (Oklahoma, Utah, Texas, Wisconsin, and South Dakota) and about 20 that are seeking such authority. Conversely, 44 states have received delegated implementation authority for the NPDES effluent permit program (EPA 1999a). Notably, delegation for the effluent permit program is funded, and delegation for and implementation of the biosolids program is not.

Proposed Regulation

40 CFR 503 was published for public comments on February 6, 1989. EPA’s original risk assessment (see Chapter 5 for further information) defined the at-risk population as the most exposed individual (MEI). The MEI is a person who is maximally exposed to a pollutant in biosolids for a lifetime. EPA conducted an aggregate public-health risk assessment that estimated the risk from land application of biosolids in the absence of any regulation. That aggregate assessment found that the risk would be less than one cancer case per year and that approximately 1,000 persons would exceed a threshold lead concentration and 500 would experience some lead-related health effects. With the final regulation in place, the resultant risk was predicted to be less than one cancer case, less than one person exceeding a threshold blood lead level, and less than one person experiencing adverse lead effects (EPA 1993). In addition, this risk would present itself only at such time as all assumptions in the risk assessment were fulfilled.

The Cooperative State Research Service Technical Committee W-170, composed of university researchers, organized a Peer Review Committee (PRC) from academia, EPA, environmental groups, and units of state and local government to provide expert and extensive comments to EPA on the proposed rule (Cooperative State Research Service Technical Committee W-170 1989). Two critical points were raised during the public comment period by the PRC: (1) The MEI was modeled with multiple layers of conservative exposures that could not exist in reality, and this contradicted the notion of reasonably anticipated adverse effects; and (2) the research for metal uptake was based on metal salts and pot studies in greenhouses rather than field research. They also recommended a risk-based approach to pathogens. Al-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

though EPA had an official policy to promote beneficial use of biosolids, the proposed regulation would have substantially curtailed such use, thus encouraging increased surface disposal and incineration.

As a result of this extensive peer review, EPA initiated additional research and substantially modified the risk assessment and ultimately the regulation. For example, EPA decided to use a highly exposed individual (HEI) rather than an MEI in the risk assessment. The HEI is a person who remains for an extended period at or adjacent to the site where maximum exposure occurs. The HEI represented a more reasonable case of exposure and still provided multiple safety factors of protection (EPA 1993, 1995a).

Final Regulations

There are three major categories of requirements establishing biosolids quality and site-management criteria for land application. Each of these categories is further divided into two sections. When biosolids meet the strictest section in all three categories, it is considered exceptional quality (EQ). Management-practice requirements establish site restrictions and limit application rates on agricultural land for the remaining non-EQ biosolids. The three requirement categories that establish biosolids quality are as follow:

  • Pollutant concentrations versus ceiling concentrations.

  • Class A pathogen criteria versus Class B pathogen criteria that include management practices.

  • Process-control criteria to reduce attraction to vectors versus physical barriers from vectors.

Biosolids that meet the requirements to be deemed EQ can be publicly distributed without further regulation under 40 CFR 503. (If biosolids do not meet the pollutant concentration limits and the other requirements, they can still be publicly distributed as long as an information sheet is included that specifies a maximum annual application rate.) It is further stipulated that biosolids must be land applied at an “agronomic rate” to not exceed the nitrogen requirements for the crop grown. This stipulation is to avoid loss from the root zone to the groundwater and to avoid excessive nitrogen buildup that may ultimately run off to surface water.

The Part 503 federal regulations for pathogen and vector attraction control are and have been technologically based instead of risk based. That is in part due to unreliable pathogen assays and insufficient and variable data with respect to the fate and transport of pathogens in the natural environment (see Chapter 6 for more details).

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Pollutant Concentrations

Specific pollutant concentrations were derived for nine metals (EPA 1995a). The risk assessment examined 14 pathways of exposure and a maximum cumulative loading rate was determined for the most limiting pathway for each pollutant. These values are shown in column 2 of Table 2–1.

Assumptions were then made that a site was used for 100 consecutive years at a loading rate of 10 MT/hectare per year. Next, a back calculation was used to determine a maximum concentration in the biosolids that would not allow the maximum cumulative loading rate to be attained. The pollutant concentration limits are intended to define biosolids that can be land applied without requiring the applier to track cumulative pollutant loadings. The methods used by EPA to identify the pollutant concentration limits are described in Chapter 5. That concentration became the pollutant concentration limit in all but two cases (see below). The current pollutant concentration limits are shown in column 3 of Table 2–1.

A National Sewage Sludge Survey (NSSS) was conducted by EPA (1990) for the purpose of gathering needed data on sewage sludge quality in the nation. The ceiling limit was set at the 99th percentile level found in the NSSS or the risk-based number, whichever was greater. The current ceiling limit concentrations are shown in column 1 of Table 2–1. The risk-derived number became the ceiling limit only for chromium (which was later deleted from regulation; see discussion later in this chapter), selenium, and nickel.1 In those cases, the 99th percentile value became the pollutant concentration limit. Currently, both the ceiling concentration and pollutant concentration limits are risk based for nickel and selenium.

Thus, land-applied biosolids that contain chemical concentrations less than those shown in column 3 of Table 2–1 do not need to track cumulative loadings to sites, because it is assumed that loadings will never approach the limits shown in column 2. If land-applied biosolids have any chemical concentrations between the values of column 3 and column 1, then cumulative loading records must be kept for any such bulk application.

It is important to note that when biosolids are sold or given away in a bag or container that weighs less than 1 MT, it must meet the strictest standards for pathogen and vector control but does not need to meet the pollutant concentration limits shown in column 3 of Table 2–1. As noted previously, if it does not meet the column 3 limits, an information sheet must be supplied

1  

The risk-based number and 99th percentile level found in the NSSS were the same for nickel.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–1 Pollutant Concentration Limits and Loading Rates for Land Application in the United States

Pollutant

(1) Ceiling Concentration Limit (mg/kg)a

(2) Cumulative Loading Rate Limit (kg/ha)a

(3) Pollutant Concentration Limit (mg/kg)a

(4) Annual Pollutant Loading Rate for Distributed Biosolids Exceeding Column 3 (kg/ha/y)a

Arsenic

75

41

41

2.0

Cadmium

85

39

39

1.9

Copper

4,300

1,500

1,500

75

Lead

840

300

300

15

Mercury

57

17

17

0.85

Molybdenum

75

-

-

-

Nickel

420

420

420

21

Selenium

100

100

100

5

Zinc

7,500

2,800

2,800

140

Applies to:

All biosolids that are land applied

Bulk biosolids

Bulk or baggedb biosolids

Baggedb biosolids where at least one element does not meet column 3

aDry weight basis.

bBagged biosolids are sold or given away in a bag or container containing less than 1 metric ton (MT).

Abbreviations: mg, milligram; kg, kilogram; ha, hectare; y, year.

Source: Adapted from 40 CFR, Part 503.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

or instructions printed on the bag that prescribe loading rates that will not exceed annual loading rates shown in column 4. Because of the perceived infrequent use of this exception and the difficulty with tracking its use, the committee concluded that it would be simpler to require that all biosolids sold or given away be EQ.

Pathogen Control

Biosolids are divided into Class A and Class B on this basis of their pathogen content and control. Class A biosolids must undergo more extensive treatment than Class B biosolids (described below) to reduce pathogens, including bacteria, enteric viruses, and viable helminth ova, to below detectable amounts. Once these goals are achieved, Class A biosolids can be land applied without any pathogen-related restrictions at the site. Biosolids having the least further restrictions on land application are those meeting the Class A pathogen requirements, the vector control requirements, and the high-quality pollutant concentration limits for metals. If all these requirements are met, the biosolids can be used with no more restrictions than any other fertilizer or soil-amendment product.

The Class B pathogen requirements were developed from the 1979 40 CFR 257 regulations for processes to significantly reduce pathogens (PSRP). In the initial development of those requirements, a PSRP was defined as a process that reduces pathogenic viruses, Salmonella bacteria, and indicator bacteria (fecal coliform) by at least 1 log (90%) (EPA 1989).

The Class B biosolids requirements are intended to ensure that pathogens in biosolids have been reduced to amounts that are protective of public health and the environment under the specific use conditions. As a central element of the Class B criteria, site restrictions designed to minimize potential for human and animal contact apply until environmental factors have further reduced pathogens to low amounts. Thus, packaged Class B biosolids cannot be sold or given away for land application at public-contact sites, lawns, and home gardens but can be used in bulk quantities at appropriate types of land-application sites, such as agricultural lands, forests, and mine reclamation sites, provided the biosolids meet limits on pollutants, vector-attraction reduction, and other management requirements of Part 503 (EPA 1993). In addition, biosolids can be used as municipal-solid-waste (MSW) landfill cover in compliance with 40 CFR Part 258.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Class A Pathogen Requirements

The Class A pathogen criteria require that both treatment-process control requirements and prescribed densities of either fecal coliform or Salmonella are satisfied. Pathogen criteria must be met at the same time or before the vector-attraction reduction requirements are met. One of the following organism density requirements listed below must be satisfied for all Class A alternatives:

Fecal Coliform Density Requirements: The fecal coliform density must be less than 1,000 most probable number (MPN) per gram (g) of total solids (TS), and that must be satisfied immediately after the treatment process is completed. If the material is bagged or distributed at that time, no retesting is required. If the material is bagged, distributed, or land applied at a later time, it must be retested and the density requirement satisfied to ensure that regrowth of bacteria has not occurred.

Salmonella Density Requirements: The Salmonella density must be less than 3 MPN per 4 g of TS, and that must be satisfied immediately after the treatment process is completed. If the material is bagged or distributed at that time, no retesting is required. If the material is bagged, distributed, or land applied at a later time, it must be retested and the density requirement satisfied to ensure that regrowth of bacteria has not occurred.

In addition, one of the following treatment processes listed must be met to be designated Class A biosolids (EPA 1999b). The goal of these processes is to reduce pathogen densities below specified detection limits for three types of organisms: Salmonella sp. (<3 MPN per 4g TS), enteric viruses (<1 plaque forming unit [PFU] per 4 g TS), and helminths (<1 viable organism per 4 g TS).

Alternative 1—Temperature and Time Process: These criteria were based on a time-temperature relationship related to pasteurization studies and to composting data. This alternative has been and is still used for aerobic digestion and anaerobic digestion. An increased sewage-sludge temperature must be maintained for a prescribed period according to the guidelines summarized in Table 2–2.

Alternative 2—Alkaline Treatment Process: The pH of the sewage sludge must be raised to greater than 12 for at least 72 hours (h). During this time, the temperature of the sewage sludge must be greater than 52°C for at least 12 h. In addition, after the 72-h period, the sewage sludge must be air dried to at least 50% TS.

Alternative 3—Prior Test for Enteric Virus and Viable Helminth Ova: The sewage sludge must be analyzed for the presence of enteric viruses

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–2 Guidelines for Temperature Treatments

Total Solids

Temperature

Time

Equation, D=Time in Days, t=Temp in °C

Notes

≥7%

≥50°C

≥20min

 

No heating of small particles by warmed gases or immiscible liquid

≥7%

≥50°C

≥15s

 

Small particles heated by warmed gases or immiscible liquid

<7%

>50°C

≥15s to <30 min

 

 

<7%

≥50°C

≥30min

 

 

Note: Temperatures calculated using the appropriate equation must never be less than 50°C. The time values are not used in the calculations, but are provided to indicate the prescribed duration that temperature must be maintained.

Source: EPA 1999b.

and viable helminth ova. If the sewage sludge is analyzed before pathogen-reduction processing and found to have densities of enteric virus of less than 1 plaque-forming unit (PFU) per 4 g of TS and viable helminth ova of less than 1 per 4 g of TS, the sewage sludge is considered Class A biosolids with respect to enteric virus and viable helminth ova until the next monitoring event. If the sewage sludge is analyzed before pathogen-reduction processing and found to have densities of enteric virus greater than or equal to 1 PFU/4 g of TS or viable helminth ova of more than 1 per 4 g of TS and is tested again after processing and found to have densities of enteric virus of less than 1 PFU/4 g of TS and viable helminth ova less than 1 per 4 g of TS, the sewage sludge is considered Class A biosolids when the treatment process is operated under the same conditions that successfully reduced enteric virus and helminth ova.

Alternative 4—Post-Test for Enteric Virus and Viable Helminth Ova Process: If the sewage sludge is not analyzed before pathogen-reduction processing for enteric viruses and viable helminth ova, the sewage-sludge density of enteric viruses must be less than 1 PFU/4 g of TS, and the density of viable helminth ova must be less than 1 per 4 g of TS at the time the sew-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

age sludge is used, disposed of, or prepared for sale or giveaway in a bag or container or when the biosolids meets EQ requirements.

Alternative 5—Processes to Further Reduce Pathogens (PFRP):

Alternative 5a—Composting Process: Compost the sewage sludge using either within-vessel or static-aerated-pile composting methods and maintain the temperature of the sewage sludge at 55°C or higher for 3 days, or compost the sewage sludge using windrow composting methods and maintain the temperature of the sewage sludge at 55°C or higher for 15 days or longer. During this period, a minimum of five windrow turnings are required.

Alternative 5b—Heat Drying Process: Dry the sewage sludge by direct or indirect contact with hot gases to reduce the moisture content of the sewage sludge to 10% or lower. Either the temperature of the sewage-sludge particles must exceed 80°C or the wet bulb temperature of the gas in contact with the sewage sludge leaving the dryer must exceed 80°C.

Alternative 5c—Heat Treatment Process: Heat liquid sewage sludge to a temperature of 180°C or higher for 30 min.

Alternative 5d—Thermophilic Aerobic Digestion Process: Agitate liquid sewage sludge with air or oxygen to maintain aerobic conditions. The mean cell residence time for the sewage sludge must be 10 days at 55°C to 60°C

Alternative 5e—Beta Ray Irradiation Process: Irradiate the sewage sludge with beta rays from an accelerator at a dose of at least 1.0 megarad at room temperature.

Alternative 5f—Gamma Ray Irradiation Process: Irradiate the sewage sludge with gamma rays from certain isotopes, such as cobalt 60 and cesium 137, at a dose of at least 1.0 megarad at room temperature.

Alternative 5g—Pasteurization Process: Maintain the temperature of the sewage sludge at 70°C or higher for 30 min or longer.

Alternative 6—Process Equivalent to Process to Further Reduce Pathogens (PFRP): Treat the sewage sludge in a process that is equivalent to PFRP, as approved by the permit authority. To obtain a Class A biosolid rating, the process must reduce Salmonella species or fecal coliforms to below Class A criteria and must operate under the specified conditions used in its application demonstration to the EPA Pathogen Equivalency Committee (see below).

Class B Pathogen Requirements

In addition to management-practice requirements, including site restric-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

tions, the Class B pathogen control requirements mandate that one of the following be satisfied before land application:

Fecal Coliform Limitation: Compliance with the fecal coliform limitation for Class B biosolids must be demonstrated by calculating the geometric mean of at least seven separate samples. (TS analysis must be done on each sample.) The geometric mean must be less than 2,000,000 MPN or colony-forming units (CFU) per g of TS.

Aerobic Digestion: Agitate the sewage sludge with air or oxygen to maintain an aerobic condition for a mean cell residence time and temperature between 40 days at 20°C and 60 days at 15°C. (This process cannot be satisfied during the winter in most of the northern United States without additional measures being taken to maintain adequate temperatures.)

Anaerobic Digestion: Treat the sewage sludge 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 must be between 15 days at 35°C to 55°C and 60 days at 20°C. Straight-line interpolation to calculate mean cell residence time is allowable when the temperature is between 35°C and 20°C.

Lime Stabilization: Add sufficient lime to the sewage sludge to raise the pH to 12 after 2 h of contact.

Air Drying: Dry the sewage sludge on sand beds or in paved or unpaved basins for a minimum of 3 months. During 2 of the 3 months, the ambient average daily temperature must be above 0°C.

Composting: Compost the sewage sludge using either within-vessel, static-aerated-pile, or windrow composting methods and raise the temperature of the sewage sludge to 40°C or higher for 5 days. For 4 h at some point during each of the 5 days, the temperature in the compost pile must exceed 55°C.

Process Equivalent to Process to Significantly Reduce Pathogens (PSRP): Treat the sewage sludge in a process that is equivalent to a PSRP, as approved by the permit authority.

Over the past 15 years, two processes have been approved as PSRP equivalents by the EPA Pathogen Equivalency Committee (PEC). These are the N-Viro alkaline stabilization process and the Synox OxyOzone process. Both processes have been upgraded to PFRP status in more recent studies. Specifically, the N-Viro process meets the Class B equivalency criteria for alkaline stabilization, and the Synox OxyOzone process meets the criteria of pathogen monitoring from influent to effluent.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Reduction of Vector Attraction

Vector-attraction reduction may be classified as long-term or short-term stabilization or may be accomplished through physical barriers. Long-term stabilization is defined as the biological degradation of the putrescible organics and results in a reduction of vector attraction. One of 10 options may be used to satisfy vector control. The first five options below are considered long-term stabilization, and the next three are considered short-term stabilization (inhibit biological activity before application) and must be demonstrated at the time of use to ensure that the criteria are satisfied. It should be stressed that when biosolids are applied to land, the vector-attraction-reduction requirements must be satisfied. This can be a potential issue with the short-term options since they are reversible. It should also be noted that treatment should be complete prior to land application so that further reaction does not occur in the field, which may result in the release of odorants. One of the following eight vector control requirements may be used to qualify as EQ biosolids:

Volatile Solids Reduction: The mass of volatile solids in the sewage sludge shall be reduced by a minimum of 38%.

Specific Oxygen Uptake Rate: The specific oxygen uptake rate (SOUR) for aerobic sewage sludge shall be equal to or less than 1.5 milligrams (mg) of oxygen per hour per gram of TS on a dry-weight basis, corrected to 20°C.

Anaerobic Bench-Scale Test: Demonstrate through additional digestion in a bench-scale test that additional volatile solids reduction for anaerobically digested sewage sludge is less than 17%. This can be demonstrated by anaerobically digesting a portion of the previously digested sewage sludge in the laboratory in a bench-scale unit for 40 additional days at a temperature between 30°C and 37°C This requirement is satisfied when at the end of the test, volatile solids have been reduced by less than 17%, as measured from the beginning to the end of the test.

Aerobic Bench-Scale Test: Demonstrate through additional digestion in a bench-scale test that additional volatile solids reduction for aerobically digested sewage sludge is less than 15%. This can be demonstrated by aerobically digesting a portion of the previously digested sewage sludge at a concentration of 2% solids or less in the laboratory in a bench-scale unit for 30 additional days at a temperature of 20°C. Sewage sludge with a higher percentage of solids must be diluted with effluent down to 2% at the start of the test. This requirement is satisfied when at the end of the test, volatile solids have been reduced by less than 15%, as measured from the beginning to the end of the test.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Aerobic Process (for Compost): The sewage sludge must be treated in an aerobic process for 14 days or longer. During that time, the temperature of the sewage sludge must be higher than 40°C and the average temperature of the sewage sludge must be higher than 45°C.

pH Adjustment: The pH of the sewage sludge must be raised to 12 or higher by alkali addition and, without the addition of more alkali, remain at 12 or higher for 2 h and then at 11.5 or higher for an additional 22 h.

Drying Without Primary Solids: 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% based on the moisture content and total solids prior to mixing with other materials.

Drying with Primary Solids: 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% based on the moisture content and total solids prior to mixing with other materials.

In place of the process-based requirements, one of the following two requirements may be utilized during or after land application and are considered physical barriers to vector attraction:

Injection: No significant amount of the biosolids can be present on the land surface within 1 h of biosolids injection.

Incorporation: The biosolids must be incorporated within 6 h of surface application or as approved by the permit authority.

Table 2–3 summarizes the above requirements.

Treatment Design Standards

Sewage sludge treatment technology not only provides the primary mechanism for pathogen reduction and the necessary stabilization to reduce biosolids attraction as a food source for vectors but also provides the means to reduce odors and related public nuisance and public health concerns. Although 40 CFR 503 provides prescriptive standards for treatment process control, the Great Lakes-Upper Mississippi River Board of State and Provincial Public Health and Environment Managers (GLUMB) report Recommended Standards for Wastewater Facilities (GLUMB 1997) (commonly referred to as the “Ten States Standards”) is used as a basis for minimum design requirements in many states but does not require the minimum criteria for many of the PSRPs. The committee concludes that tightening the minimum treatment

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–3 Summary of Requirements for Vector Attraction Reduction Under Part 503

Requirement

What Is Required?

Most Appropriate for:

Option 1

503.33(b)(1)

At least 38% reduction in volatile solids during sewage sludge treatment

Sewage sludge processed by

–Anaerobic biological treatment

–Aerobic biological treatment

–Chemical oxidation

Option 2

503.33(b)(2)

Less than 17% additional volatile solids loss during bench-scale anaerobic batch digestion of the sewage sludge for 40 additional days at 30°C to 37°C (86°F to 99°F)

Only for anaerobically digested sewage sludge

Option 3

503.33(b)(3)

Less than 15% additional volatile solids reduction during bench-scale aerobic batch digestion for 30 additional days at 20°C (68°F)

Only for aerobically digested sewage sludge with 2% or less solids

Option 4

503.33(b)(4)

SOUR at 20°C (68°F) is ≤1.5 mg of oxygen/h/g total sewage sludge solids

Sewage sludges from aerobic processes (should not be used for composted sewage sludges)

Option 5

503.33(b)(5)

Aerobic treatment of the sewage sludge for at least 14 days at over 40°C (104°F) with an average temperature of over 45°C (113°F)

Composted sewage sludge (Options 3 and 4 are likely to be easier to meet for sewage sludges from other aerobic processes)

Option 6

503.33(b)(6)

Addition of sufficient alkali to raise the pH to at least 12 at 25°C (77°F) and maintain a pH ≥12 for 2 h and a pH ≥11.5 for 22 more hours

Alkali-treated sewage sludge (alkalies include lime, fly ash, kiln dust, and wood ash)

Option 7

503.33(b)(7)

Percent solids ≥75% prior to mixing with other materials

Sewage sludges treated by an aerobic or anaerobic process (i.e., sewage sludges that do not contain unstabilized solids generated in primary wastewater treatment)

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Option 8

503.33(b)(8)

Percent solids ≥90% prior to mixing with other materials

Sewage sludges that contain unstabilized solids generated in primary wastewater treatment (e.g., any heat-dried sewage sludges)

Option 9

503.33(b)(9)

Biosolids are injected into soil so that no significant amount of sewage sludge is present on the land surface

1 h after injection, except Class A biosolids which must be injected within 8 h after the pathogen reduction process

Biosolids applied to the land or sewage sludge placed on a surface disposal site; domestic septage applied to agricultural land, a forest, or a reclamation site or placed on a surface disposal site

Option 10

503.33(b)(10)

Biosolids are incorporated into the soil within 6 h after application to land or placement on a surface disposal site, except Class A biosolids, which must be applied to or placed on the land surface within 8 h of the pathogen reduction process

Biosolids applied to the land or sewage sludge placed on a surface disposal site; domestic septage applied to agricultural land, forest, or a reclamation site or placed on a surface disposal site

Option 11

503.33(b)(11)

Sewage sludge placed on a surface disposal site must be covered with soil or other material at the end of each operating day

Sewage sludge or domestic septage placed on a surface disposal site

Option 12

503.33(b)(12)

pH of domestic septage must be raised to ≥12 at 25°C (77°F) by alkali addition and maintained at ≥12 for 30 min without adding more alkali

Domestic septage applied to agricultural land, a forest, or a reclamation site or placed on a surface disposal site

 

Source: Adapted from EPA 1999b.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

design standards by control agencies and GLUMB to reflect and be consistent with the requirements of 40 CFR 503 would accomplish much in the area of compliance and odor abatement. Since odors are a primary source of public complaints, adequacy of treatment cannot be over-emphasized. Odors are a function of treatment quality and are minimized with effective treatment and management.

Rule Modifications

Two lawsuits were brought shortly after the 1993 rule promulgation, involving three chemical pollutants (chromium, selenium, and molybdenum), that caused modifications to the land application section of 40 CFR 503. The first lawsuit centered on the fact that the pollutant concentrations for chromium and selenium were not based on risk, and the petition argued that EPA was required under the CWA to establish such limits based only on risk. The court agreed and required that the risk-based values become the pollutant concentrations in all cases. This meant that the ceiling concentrations in those cases would also be the risk-based number. (The pollutant limit for selenium was therefore increased from 36 [99%] to 100 milligrams per kilogram [mg/kg] [risk based].) The suit also charged that the research used to assess phytotoxicity as the limiting pathway for chromium was based on pot studies and not field research, which showed no such effects. The court again agreed, but EPA chose not to replace the standard with the next limiting pathway, because it would set the limit at 12,000 mg/kg. Determining that no biosolids would have chromium concentrations that high, chromium was deleted from regulation under 40 CFR 503 (EPA 1995b).

The second lawsuit asserted that the research used to determine the limiting pathway for molybdenum (animal ingesting feed grown on biosolids-treated fields) was not scientifically supportable, and calculated amounts of molybdenum that plants take in (e.g., plant uptake slopes) were based on highly contaminated sewage sludge. EPA agreed to conduct more research to better establish risk levels. At this time, the cumulative loading limit and pollutant concentration limits have been deleted for molybdenum and only the ceiling concentration remains (see Table 2–1) (EPA 1994). O’Connor et al. (2001) conducted a modified risk assessment and recommended values for the deleted tables. However, EPA has not acted to revise the molybdenum standard.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Revision of Regulations

EPA was court-ordered to promulgate a second round of 40 CFR 503 regulations by December 15, 2001. In response, EPA conducted a pollutant screening hazard identification exercise and subsequently determined that the only pollutants posing a potential risk that were not regulated in the first round were dioxin and dioxin-like compounds. On December 23, 1999, EPA published proposed risk-based regulations for 7 dioxin, 10 furan, and 12 coplanar PCB congeners (EPA 1999c). Once again, EPA received numerous comments on the proposal representing an array of perspectives. As a result of the public comments received, EPA contracted for a new biosolids survey to evaluate biosolids concentrations of the congeners of interest; contracted for a new risk assessment using probabilistic or Monte Carlo simulation methods rather than the deterministic methods used for the proposed rule; and engaged a peer-review panel. Agreement was recently reached between all parties to extend the deadline for the Round 2 land-application rule until October 17, 2003. EPA (2002a) published a Notice of Data Availability on June 12, 2002 that summarizes new data and a revised risk assessment.

Public Issue Forums

A number of public forums have been critical of the final Part 503 regulations or of EPA’s commitment to oversight in implementing the regulations. The criticisms include the following:

  • After promulgation of the Part 503 regulations in 1993, EPA decided that the land application of biosolids was a low risk to public health and therefore the biosolids oversight program was given a low priority in its annual budget. That decision was based on the aggregate risk assessment, which showed negligible adverse effects even without regulation. However, the decision has had far-reaching negative consequences and has forced the agency and state programs to operate in a conflict resolution mode rather than in an efficient proactive mode. As a result, resources are expended only after a problem is identified rather than working to avoid the problem in the first place. This policy decision provides little flexibility for dealing with perceived effects or emerging issues.

  • A committee of the National Research Council (NRC) was convened in 1993 to examine the science behind the federal biosolids regulations and the use of biosolids on food-chain crops. The NRC (1996) report concluded that “if the regulations are properly adhered to, the use of [biosolids] on food-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

chain crops for human consumption is protective of human health.” The report also recommended that additional research be conducted in certain areas, particularly in pathogen control, and that EPA take steps to ensure that the regulations were followed (see also Chapter 1 and Box 1–2 for more detail on that committee’s recommendations.)

  • There have been several allegations of human deaths and illnesses caused by land application of biosolids. However, there has been no documented scientific evidence to substantiate those claims.

  • There have also been several allegations of animal deaths caused by land application of biosolids (e.g., cases in Colorado and Georgia). Supporting evidence to substantiate these allegations has not been documented in the scientific literature, but EPA did investigate them and has produced reports on their findings.2,3 It found no substantiation for the allegations.

  • The National Institute for Occupational Safety and Health (NIOSH) published a Hazard ID 10 (NIOSH 2000) in August 2000 based on a Health Hazard Evaluation Report (Burton and Trout 1999). The reports were based on an investigation of worker health effects at the LeSourdsville, Ohio, wastewater treatment facility, owned and operated by the Butler County Health Department. The workers were involved in the treatment, storage, and land application of sewage sludge. There was a lapse between the time of the workers becoming ill and the involvement of NIOSH. At the time of the illnesses, LeSourdsville had operating difficulties, and the sewage sludge produced did not meet the Class B biosolids requirements (Lodor 2001). For example, the sewage sludge had fecal coliform densities more than 4 times the allowed limit. At the time of the NIOSH inquiry in 1999, coliform densities were well below the limit. However, it was also found that good hygiene protocol was not generally followed by the biosolids workers, thus precluding any relevant correlations. NIOSH recently released guidance for controlling potential risks to workers exposed to Class B biosolids (NIOSH 2002). This document supercedes the Hazard ID 10 document.

  • A congressional hearing before the Committee on Science chaired by Congressman F.James Sensenbrenner, Jr., was held on March 22, 2000, to hold EPA accountable for how it dealt with criticism and the public in general regarding its biosolids program. (The hearing was not intended to question the science behind the existing regulations; see also Kester 2000a.)

2  

D.H.Gould, G.H.Loneragan, Integrated Livestock Management Group; G.K.Beck, and H.D.Fraleigh, Colorado State University; and R.B.Brobst, EPA, unpublished data, no date.

3  

J.W.Gaskin and E.W.Tollner, University of Georgia, unpublished data, no date.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • An independent program audit by the EPA Office of the Inspector General (OIG) (EPA 2000b) requested by the EPA Office of Water (OW) concluded that there was a significant lack of oversight and resources committed by the EPA Office of Enforcement and Compliance Assurance (OECA), the Office of Wastewater Management (OWM), the Office of Science and Technology (OST), and the Office of Research and Development (ORD). Therefore, EPA could not guarantee that land-application and public-distribution practices were conducted in compliance with the CWA regulations and thus protective of public health and the environment. Notably, the Inspector General did not claim that the regulations were not protective but rather criticized EPA’s inability to confirm compliance. However, OW and OECA officially declined to take action on many of the OIG’s recommendations due to budgetary constraints and other program priorities (EPA 2000c, 2001a). The OIG subsequently sent a letter stating that OW’s and OECA’s formal response was inadequate. The OIG suggested alternative means for fulfilling the report recommendations and broadly criticized the lack of commitment to the biosolids program and the absence of consensus regarding program implementation within EPA (EPA 2001b). They also requested a timeline from OW and OECA for establishing a new biosolids goal and identifying needed resources to accomplish it under the Government Performance and Results Act (GPRA). The OW and OECA responded with a letter (EPA 2002b) stating that to fulfill the OIG recommendations would require budget and staff resources the agency simply did not have. Thus, the OW and OECA position continues to be that biosolids are a low risk to human health and the environment. Given the ongoing need for OW and OECA to set priorities among its many programs concerning public health and environmental protection, they maintain that their limited resources are better allocated elsewhere.

  • In late 2000, EPA requested and sponsored an NRC study to review information on the land application of biosolids and reexamine the risk-assessment methods used in developing the Part 503 regulations in light of recent research findings and advances in risk assessment to determine whether the standards were still adequately protective of human health. This study is also reviewing pathogen control, whether a risk-based approach for pathogens should be pursued, and whether chemical and pathogen risk-assessment approaches can be integrated. This report is the product of that committee.

  • The EPA OIG released a status report of EPA’s biosolids program in March 2002 (EPA 2002c). The major findings of the report were

    • EPA places a low priority on the biosolids program, and the number of program staff assigned to it have been declining.

    • EPA has delegated authority of the biosolids program to only five states. EPA cannot be certain that all citizens in nondelegated states are provided at least the same level of protection as in the federal program.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • There can be wide variation in how states manage biosolids.

  • EPA has no formal process for tracking health complaints. Of 21 complaints that were brought to the OIG’s attention, 14 were investigated by EPA or a state agency, five were not report to EPA or the state, and two were not related to biosolids.

  • EPA has no plans for conducting a comprehensive evaluation and monitoring study to address risk assessment uncertainties. More research on pathogen testing appears to be needed.

  • In reviewing EPA’s relationship with the Water Environment Federation (WEF), OIG found that 96% of the $12.9 million given to WEF and its research organization over a 3-year period was congressionally mandated and EPA had no discretion in awarding the funds.

  • The general public has concerns about the effects of biosolids on health, quality of life, and natural resources. Public perception of land application of biosolids has a significant impact on the implementation of the program.

EPA Resources

The committee notes that it has long been recognized by those within EPA working in the biosolids field and state agencies required to implement the biosolids program that EPA disinvestment in the program has caused an inability to adequately ensure that the regulations are followed. Although more than 40% of the capital cost and the operation and maintenance expense of wastewater treatment is expended on biosolids treatment and management (much of which is from federal dollars in the form of grants and low-interest loans), less than one-tenth of 1% of EPA’s budget is devoted to the biosolids program. Of EPA’s $7.8 billion budget in FY 2001, only about $4 million or 0.05% was devoted to biosolids staff and the program (J.Walker, EPA, presentation at Biosolids Regulator Workshop, Potomac, Maryland, June 28, 2001).

The Wisconsin Department of Natural Resources (WDNR) represents all state environmental protection agencies to EPA, including the EPA Biosolids Program Implementation Team (BPIT), on a number of biosolids issues. In this capacity, the WDNR has sent five letters to EPA between 1998 and 2001 seeking program support (Meyer 1998; Kester 2000b,c; 2001a,b). The areas of most critical need include technical support on biosolids treatment for pathogen and vector-attraction controls and staffing. The Pathogen Equivalency Committee (PEC) comprises agency experts who primarily serve as volunteers to provide technical support regarding the adequacy of treatment technology with respect to pathogen control. Each of the 10 EPA Regions

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

have between 0.2 and 2 full-time employees (FTEs), and a total nationwide of 8.8 FTEs, working in all areas of biosolids management. The EPA ORD has 2 FTEs devoted to the program, and EPA headquarters has 4.8 FTEs (J.Walker, EPA, presentation at Biosolids Regulator Workshop, Potomac, Maryland, June 28, 2001). In addition to these obvious staff shortages, consideration should be given to train new experts in the field to replace existing staff, many of who are approaching retirement.

State Programs

Many states are responsible for implementing biosolids programs by their own statutes and regulations. In those states, biosolids application falls under both EPA and state rules, with federal rules being required minimum standards. Some municipalities (or local units of government) in the United States have adopted local ordinances pertaining to land application. The authority of a municipality, and thus the scope that a local ordinance can address, varies between the states (Harrison and Eaton 2001). Thus, the ability of a local ordinance to withstand legal challenge depends on the state. As noted previously, only five states (Oklahoma, Utah, Texas, Wisconsin, and South Dakota) have received official delegated authority from EPA to administer the federal regulations for biosolids. Several states have submitted requests for delegated authority but in many cases experience long waiting periods for a review of that request (e.g., Vermont and Iowa) or encounter other legal or technical roadblocks. For example, Colorado, Indiana, and South Carolina have had legal issues with self-audit protection laws, which are inconsistent with federal requirements. North Carolina has issues with implementing agreements compliant with endangered species protection administered through the U.S. Fish and Wildlife Service, and Michigan has potential issues with authority over non-Native-American wastewater generated or used on Native American land. Nevertheless, all states have varying degrees of commitment for biosolids program administration. Figure 2–3 shows the number of full-time employees (FTEs) working for state biosolids programs. This figure is based on direct communication between the WDNR and each state (WDNR, unpublished data, 2001).

EUROPEAN BIOSOLIDS MANAGEMENT

The management of biosolids in Europe varies from country to country, as do the standards applied, their derivation, and their enforcement. This situation is readily apparent when U.S. regulations and their varying levels of

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

FIGURE 2–3 Number of FTEs dedicated to state biosolids programs. Figures do not include septage staff. Source: EPA 2002c.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

enforcement are compared with those of European countries. Some of the substantial differences in the contaminant standards between Europe and the U.S. are, in part, due to differences in approaches to environmental protection and regulatory intent (public health and environmental protection). For example, some European countries have taken the approach of minimizing any accumulation of metals beyond background environmental levels, whereas other European countries and the U.S. have performed risk assessments to determine land-application concentrations that are protective of reasonably anticipated adverse effects. Even the latter approach has lead to substantially different standards between some countries. A variety of factors influence the outcomes of risk assessment (discussed in Chapter 5), but the major contributing factor to different risk-based standards between countries is each country’s selection of target organism (humans, animals, plants, soil organisms) to protect. Although it was beyond the scope of this report to prepare a comprehensive evaluation of differences between U.S. standards and those of other countries, it is important that the differences be acknowledged and the bases for those differences used to inform future risk assessments. This section provides an overview of how different European countries have approached the management of biosolids for land application.

The European Union is composed of 15 member nations. The Council of European Communities (1986) published the Sewage Sludge Directive (86/278/EEC). All members had to promulgate their own version of the directive as national regulations by 1989. The directive included a recommended range of pollutant concentration values for seven constituents in biosolids for member nations to use in adopting their standards (see Table 2–4). However, individual nations could choose to adopt more stringent standards than those recommended in the directive. New regulations were proposed but might not be adopted until 2005 (Luca Marmo, European Commission, Brussels, personal communication, 2002).

A comprehensive review of biosolids use and disposal practices was published by the International Association on Water Quality (IAWQ), International Water Association (IWA), the Water Environment Federation (WEF), and the European Water Pollution Control Association (EWPCA) (Matthews 1996). Selected information from that review and other references has been presented with appropriate updates when available (Council of the European Communities 1986; EPA 1990, 1995a,b, 1999b; Gendebien et al. 1999; European Union 2000a,b; and European Communities 2001). Accordingly, representative data from Europe to complement U.S. information have been assembled to provide a basis for comparison and some determination of the current and future status of biosolids management.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–4 European Union Limit Values for Concentrations of Heavy Metals in Biosolids for Use on Land

 

Limit Values (mg/kg of DM)

Elements

Directive 86/278/EEC

Proposed

Cadmium

20–40

10

Chromium

-

1,000

Copper

1,000–1,750

1,000

Mercury

16–25

10

Nickel

300–400

300

Lead

750–1,200

750

Zinc

2,500–4,000

2,500

Abbreviation: DM, dry matter.

Source: Adapted from Council of the European Communities 1986.

An assessment of the status of disposal and recycling within the European community (European Communities 2001) reviewed existing legislation and regulations and provided an analysis of stakeholder positions, motivations, and constraints, as well as solutions for reducing constraints and encouraging the use of biosolids. Analysis of existing legislation indicated that specific requirements focus principally on the use of biosolids in agriculture both nationally and in Europe. The EEC directives, which have the strongest influence on biosolids use, are directive 91/271/EEC on urban wastewater treatment and 86/278/EEC on the use of biosolids in agriculture (Council of the European Communities 1986). Requirements set by the latter directive are a crucial element in the management of biosolids produced in the member states and some member states have introduced provisions that go beyond the requirements of the directive. In particular, the limit values for concentrations of heavy metals in biosolids are lower than those specified in the directive in a majority of the countries.

As indicated in Table 2–5, the countries in which the limitations on heavy metal concentrations are the most stringent are Belgium (Flanders region), Denmark, Finland, the Netherlands, and Sweden. Greece, Luxembourg, Ireland, Italy, Portugal, and Spain have set limit values similar to those in the directive; values for Poland, an accession country, are also lower than the European Union standards. The United Kingdom legislation differs by not providing any limit values for heavy metals in biosolids but rather specifying the maximum annual average loads of heavy metals to soil that are similar to the directive (Table 2–6). In addition, the regulations on biosolids use include limit values for pathogens in France, Italy, and Luxembourg and for organic

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–5 European Union Limit Values for Heavy Metals in Biosolids, milligrams per kilogram of dry matter (DM) (Italic numbers represent limit values below those required by directive 86/278/EEC.)

 

Cd

Cr

Cu

Hg

Ni

Pb

Zn

As

Mo

Co

Directive 86/278/EEC

20–40

-

1,000–1,750

16–25

300–400

750–1,200

2,500–4,000

-

-

-

Austria

2a

50a

300a

2a

25

100a

1,500a

-

-

10a

 

10b

500b

500b

10b

100b

400b

2,000b

-

-

-

10c

500c

500c

10c

100c

500c

2,000c

-

-

-

4d

300d

500d

4d

100d

150d

1,800d

-

-

-

10e

500e

500e

10c

100e

500c

2,000c

20c

20c

100c

0.7–2.5f

70–100f

70–300f

0.4–2.5f

25–80f

45–150f

200–1,800f

-

-

-

Belgium (Flanders)

6

250

375f

5

100

300

900f

150

-

-

Belgium (Walloon)

10

500

600

10

100

500

2,000

 

-

-

Denmark

- dry matter basis

0.8

100

1,000

0.8

30

12g

4,000

25h

-

-

- total phosphorus basis

100

 

 

200

2,500

10,000g

 

 

 

 

Finland

3

300

600

2

100

150

1,500

-

-

-

 

1.5i

 

 

1i

 

100I

 

 

 

 

France

20j

1,000

1,000

10

200

800

3,000

-

-

-

Germany

10

900

800

8

200

900

2,500

-

-

-

Greece

20–40

500

100–1,750

16–25

300–400

750–1200

2,500–4,000

-

-

-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

 

Cd

Cr

Cu

Hg

Ni

Pb

Zn

As

Mo

Co

Directive 86/278/EEC

20–40

-

1,000–1,750

16–25

300–400

750–1,200

2,500–4,000

-

-

Ireland

20

-

1,000

16

300

750

2,500

-

-

-

Italy

20

1,000

10

300

750

2,500

-

-

-

Luxembourg

20–40

1,000–1,750

1,000–1,750

16–25

300–400

750–1,200

2,500–4,000

-

-

-

Netherlands

1.25

75

75

0.75

30

100

300

-

-

-

Portugal

20

1000

1,000

16

300

750

2,500

-

-

-

Spain

- soil pH <7

20

1,000

1,000

16

300

750

2,500

-

-

-

- soil pH >7

40

1,750

1,750

25

400

1,200

4,000

 

Sweden

2

100

600

2.5

50

100

800

-

-

-

United Kingdom

-

-

-

-

-

-

-

-

-

-

Accession countries

 

Estonia

15

1,200

800

16

400

900

2,900

-

-

-

Latvia

20

2,000

1,000

16

300

750

2,500

-

-

-

Poland

10

500

800

5

100

500

2,500

-

-

-

aLower Austria (grade II).

bUpper Austria.

cBurgenland.

dVorarlberg.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

eSteiermark.

fCarinthia.

fThese values will be reduced to 125 (Cu) and 300 (Zn) from December 31, 2007.

gFor private gardening, lead value is reduced to 60 mg/kg of DM or 5,000 mg/kg of phosphorus.

hFor private gardening.

iTarget limit values for 1998.

j15 mg/kg of DM from January 1, 2001 and 10 mg/kg of DM from January 1, 2004.

Abbreviations: As, arsenic; Cd, cadmium; Co, cobalt; Cr, chromium; Cu, copper; Hg, mercury; Mo, molybdenum; Ni, nickel; Pb, lead; Zn, zinc.

Source: Adapted from European Communities 2001.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–6 European Union Limit Values for Amounts of Heavy Metals That May Be Added Annually to Soil, Based on a 10-Year Average

 

Limit Values (g/ha/y)

Elements

Directive 86/278/EEC

Proposed

Cadmium

150

30

Chromium

-

3,000

Copper

12,000

3,000

Mercury

100

30

Nickel

3,000

900

Lead

15,000

2,250

Zinc

30,000

7,500

Note: The component authority may decide to allow an increase in the loading rate for copper and zinc on a case-by-case basis for those plots of land that are copper-or zinc-deficient and if it has been proved by qualified expert advice that there is a specific agronomic need for the crops.

Abbreviations: g/ha/y, gram per hectare per year.

Sources: Adapted from Council of the European Communities 1986; European Union 2000b.

compounds in Austria, Belgium-Flanders, Denmark, France, Germany, and Sweden, neither of which are included in the directive (Tables 2–7 and 2–8).

In all member states, regulations on the use of biosolids specify limit values for heavy metals in soil that are similar in most cases to the requirements set in the directive (Table 2–9). Some countries have defined limit values for several categories of soil pH or limit the maximum load of heavy metals to agricultural lands on a 10-year basis. Maximum quantities of biosolids that can be applied on land have been set between 1 metric ton by the Netherlands for grasslands and 10 metric tons by Denmark per hectare and per year.

The debate on biosolids recycling and disposal differs in intensity and resolution throughout the European community. An analysis of stakeholder groups (European Communities 2001), including the farming community, landowners, industries, water and wastewater plants and companies, local authorities, national authorities, and citizens and consumer groups, indicated a significant diversity of opinion ranging from opposition to advocacy as shown below:

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–7 European Limit Values for Pathogens Concentrations in Biosolids

 

Salmonella

Other Pathogens

France

8 MPN/10 g of DM

Enterovirus: 3 MPCN/10 g of DM

Helminths eggs: 3/10 g of DM

Italy

1,000 MPN/g of DM

 

Luxembourg

 

Enterobacteria: 100/g

No egg of worm likely to be contagious

Poland

Biosolids cannot be used in agriculture if it contains Salmonella

“Parasites”: 10/kg of DM

Abbreviations: DM, dry matter; MPN, most probable number; MPCN, most probable cytophatic number.

Source: Adapted from European Communities 2001.

  • The regulatory requirements in the Netherlands and Flanders region of Belgium have prevented almost all use of biosolids in agriculture since 1991 and 1999, respectively.

  • In countries such as Denmark and the United Kingdom, new regulations are considered sufficiently strict to reduce risks to an acceptable level (Denmark), and agreement in 1998 between water and sewage operators and retailers as well as farmers’ associations and government (United Kingdom) led to the joint adoption of a “safe sludge matrix” providing for additional restrictions on the use of biosolids on agricultural land as well as the categories of crops on which biosolids may not be used.

  • In Sweden, a voluntary agreement was signed in 1994 between the Swedish Environmental Protection Agency, the Swedish Federation of Farmers (LRF), and the Swedish Water and Waste Water Association concerning quality assurances relating to the use of biosolids in agriculture. However, in October 1999, the LRF recommended that its members stop using biosolids because of quality concerns.

  • Public opinion in Germany has recently swung in favor of agricultural land application, mainly because this practice is considered economically viable and the potential risks are sufficiently reduced by the existing legislation, which is now being reviewed.

  • In Austria, France, and the Walloon region of Belgium, national (or regional) agreements have been considered, and in France, such an agreement

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–8 European Limit Values for Organic Compounds in Biosolids (milligrams per kilogram of dry matter)

 

Dioxins and Furans (PCDD, PCDF) ng TE/kg of DM

PCBs

AOX

LAS

DEHP

NPE

PAH

Toluene

Austria

100a,b,c

50e

0.2a,b,c

1e

500a,b,d

-

-

-

6d

-

Belgium (Flanders)e

 

Denmark

-

-

-

2,600

100

50

6

-

from 1/07/2000

 

1,300

50

30

3

 

from 1/07/2002

1,300

50

10

3

 

France

-

0.8f

-

-

-

 

2–5g

1.5–4h

-

Germany

100

0.2i

500

-

-

-

-

-

Sweden

-

 

0.4

-

-

100

3

5

aLower Austria.

bUpper Austria.

cVorarlberg.

dCarinthia.

eLimit values for approximately 30 organic compounds.

fSum of seven principal PCBs (PCB 28, 52, 101, 118, 138, 153, 180).

gFluoranthene, benzo[b]fluoranthene, benzo[a]pyrene.

hWhen used on pasture land.

iFor each one of the six congeners.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–9 European Union Limit Values for Heavy Metals in Soil (milligrams per kilogram of dry matter) (Shaded cells represent limit values below those required by Directive 86/278/EEC.)

 

Cd

Cr

Cu

Hg

Ni

Pb

Zn

As

Mo

Co

Directive 86/278/EEC (6<pH<7)

1–3

50–140

1–1.5

30–75

50–300

150–300

-

-

-

Austria

1.5a

100a

60a

1a

50a

100a

200a

-

-

-

 

1b

100b

100b

1b

60b

100b

300b

-

-

-

2c

100c

100c

1.5c

60c

100c

300c

-

-

-

2d

100d

100d

1d

60d

100d

300d

-

-

-

2e

100e

100e

1e

60e

100e

300e

-

10e

50e

0.5–1.5f

50–100f

40–100f

0.2–1f

30–70f

50–100f

10–200f

-

-

-

Belgium (Flanders)

0.9

46

49

1.3

18

56

170

22

-

-

Belgium (Walloon)

2

100

50

1

50

100

200

-

-

-

Denmark

0.5

30

40

0.5

15

40

100

-

-

-

Finland

0.5

200

100

0.2

60

60

150

-

-

-

France

2

150

100

1

50

100

300

-

-

-

Germany

1.5

100

60

1

50

100

200

-

-

-

Greece

1–3

-

50–140

1–1.5

30–75

50–300

150–300

-

-

-

Ireland

1

-

50

3

30

50

150

-

-

-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

 

Cd

Cr

Cu

Hg

Ni

Pb

Zn

As

Mo

Co

Directive 86/278/EEC (6<pH<7)

1–3

-

50–140

1–1.5

30–75

50–300

150–300

-

-

-

Italy

1.5

-

100

1

75

100

300

-

-

-

Luxembourg

1–3

100–200

50–140

1–1.5

30–75

50–300

150–300

-

-

-

Netherlands

0.8

100

36

0.3

35

85

140

-

-

-

Portugal

 

-soil pH<5.5

1

50

50

1

30

50

150

-

-

-

-5.5< soil pH <7

3

200

100

1.5

75

300

300

-

-

-

-soil pH >7

4

300

200

2

110

450

450

-

-

-

Spain

 

-soil pH <7

1

100

50

1

30

50

150

-

-

-

-soil pH >7

3

150

210

1.5

112

300

450

-

-

-

Sweden

0.4

60

40

0.3

30

40

100–150

-

-

-

United Kingdom

 

-5< soil pH 5.5

3

-

80

1

50

300

200

-

-

-

-5.5< soil pH <6

3

-

100

1

60

300

250

 

-6≤ soil pH ≤7

3

-

135

1

75

300

300

-soil pH >7

3

-

200

1

110

300

450

Estonia

3

100

50

1.5

50

100

300

-

-

-

Latvia

0.3–1

15–30

10–25

0.1–0.15

8–30

15–30

35–100

-

-

-

Poland

1–3

50–100

25–75

0.8–1.5

20–50

40–80

80–180

-

-

-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

aLower Austria (grade II).

bUpper Austria.

cBurgenland.

dVorarlberg.

eSteiermark.

fCarinthia.

Abbreviations: As, arsenic; Cd, cadmium; Co, cobalt; Cr, chromium; Cu, copper; Hg, mercury; Mo, molybdenum; Ni, nickel; Pb, lead; Zn, zinc.

Source: Adapted from European Communities 2001.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

was supported on the condition that additional quality controls and an insurance fund be developed. One party to the agreement (farmers’ union) asked for a ban on biosolids because current methods used are not considered sufficient to address the perceived risks related to the agricultural cycling of biosolids.

  • In Finland and Luxembourg, the farming community is generally hostile toward the use of biosolids for land application, mainly because of the pressure to use animal manure (e.g., the Finnish Union of Agricultural Producers requested a ban on the use of biosolids for land application and has renewed its stand against the use of biosolids in agriculture in 2001).

  • In Ireland and Portugal, farmers tend to support the agricultural use of biosolids for economic and for agronomic (organic matter and phosphorus content) reasons, although biosolids use in these countries has been relatively recent.

  • In Spain, Italy and Greece, available information indicates that there is little debate on use of biosolids.

The analysis of stakeholders’ positions (European Communities 2001) indicates that the main concerns on sewage sludge disposal and biosolids recycling are that the growing quantities of sewage sludge must be treated with the aim of keeping both environmental and economic costs as low as possible. Similarly, improving practices of treatment and use of biosolids is now considered essential. Moreover, within the context of uncertainties concerning the potential impacts on human health and the environment of the various disposal and recycling options, additional research is needed to increase confidence in the use of biosolids in agriculture.

Some strategies suggested by the recent European Union biosolids-management assessment for reducing constraints and encouraging recycling of biosolids include the following (European Communities 2001):

  • Certify the treatment process involved, the quality of biosolids, and recycling practices.

  • Develop a trust fund or insurance system to cover any loss of profits, damages, or other costs related to the use of biosolids in agriculture together with legal provisions to regulate producer liability.

  • Standardize science-based laws and regulations.

  • Enhance mutual confidence and communication and transfer of information between stakeholders.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • Diminish uncertainty over risks to human health and environment, and extend the assessment and dissemination of information beyond heavy metals to include organic pollutants and pathogens.

  • Develop codes of practice for the recycling of biosolids, the possible use of labels for quality assurance, and associated training programs and outreach activities for stakeholders.

When European Union biosolids-management practices are compared with those of the U.S., it is apparent that European and U.S. contaminant limits apply largely to heavy metals and are based on (1) the concentration of the biosolids itself; (2) the loading or total amount of metal that can be added and how quickly it can be applied; and (3) the maximum concentration of metals in soil allowed to build up after biosolids application.

According to an analysis of regulations in the United States and some European countries by McGrath et al. (1994), three basic approaches to setting limits were distinguished: (1) analyzing the pathways of pollutant transfer to selected target organisms and an assessment of the likely harmful effects that metals might have on the target; (2) setting limits consistent with the lowest-observed-adverse-effect concentrations, which are actual cases of effects due to metals but not necessarily derived from studies that involved applications of biosolids; and (3) attempting to match the metal inputs to soils to the small losses of metals due to crop removal, soil erosion, and leaching (metal balance approach). These approaches were considered responsible for the widely different numerical limits for metals arising either from a policy decision to reach zero impact (metals balance) and associated low levels or from approaches that allow some increase in metal concentrations in soils based on target organisms and use of associated models and sparse toxicity data. Thus, the practice of implementing vastly different regulations for biosolids application to land in the United States and within European Union member nations create differing social, economic, technological, and environmental impacts that beg consensus resolution in the scientific, technical, and regulatory communities.

Within the European Union, the intended goal and most widely applied biosolids disposition option is agricultural use. However, the selection of an option and its implementation according to European Commission directives is affected by local or national circumstances. Thus, the degree of flexibility varies. Some indication of the production and disposal of domestic sewage sludge and biosolids in Europe as of 1992 is included in Table 2–10. Notably, ocean disposal has been phased out, so that the principal disposal options now include agricultural use, landfill, and incineration. As in the United States, the

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–10 Production and Disposal of Domestic Sewage Sludge and Biosolids in European Community in 1992 (1,000 metric tons of dry matter per year [%])

Member State

Quantity

Agriculture

Landfill

Incineration

Ocean

Othera

Austria

170 (2.3)

30.6 (18)

59.5 (35)

57.8 (34)

-

22.1 (13)

Belgium

59.2 (0.8)

17.2 (29)

32.5 (55)

8.9 (15)

-

0.6 (1)

Denmark

170.3 (2.3)

92 (54)

34 (54)

40.9 (24)

-

3.4 (2)

Finland

150 (2.0)

37.5 (25)

112.5 (75)

-

-

-

France

865.4 (12.0)

502 (58)

233.5 (27)

130 (15)

-

-

Germany

2,681.2 (2.3)

724 (27)

1,448 (54)

375.2 (14)

-

134 (5)

United Kingdom

1,107 (15.0)

488 (44)

88.6 (8)

77.4 (7)

322 (30)

121 (11)

Greece

48.21b (0.6)

4.8 (10)

43.4 (90)

-

-

-

Ireland

36.7 (0.5)

4.4 (12)

16.6 (45)

-

12.8 (35)

2.9 (8)

Italy

816 (11.0)

269.2 (33)

449 (55)

16.2 (2)

-

81.6 (10)

Luxembourg

8 (0.1)

1(12)

7 (88)

-

-

-

Netherlands

335 (4.5)

87 (26)

171 (51)

10 (3)

-

67 (20)

Norway

95 (1.3)

53.2 (58)

41.8 (44)

-

-

-

Portugal

25 (0.3)

2.7 (11)

7.3 (29)

-

0.5 (2)

14.5 (58)c

Spain

350 (4.7)

175 (5)

122.5 (35)

17.5 (5)

35 (10)

-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Sweden

200 (2.7)

80 (40)

120 (60)

-

-

-

Switzerland

270 (3.6)

121.5 (45)

81 (30)

67.5 (25)

-

-

Total

7,387 (100.0)

2,690.1 (36.4)

3,066.2 (41.6)

801.4 (10.9)

380.3 (5.19)

447.1 (6)

aRecultivation, forestry, and so forth.

bOther estimates at 200,000 metric tons of dry matter per year.

cSurface water.

Source: Adapted from Matthews 1996.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

European Commission has developed regulatory limits (Sewage Sludge Directive 86/278/EEC) when biosolids are used in agriculture. The Sewage Sludge Directive requires member states to apply maximum limit values for certain heavy metals in the biosolids and in the soil to which it is applied; to pretreat sewage sludge; and to restrict its use, including the frequency and quantity of application, on certain soils.

These regulations establish conditions relating to pretreatment, nutrient needs, quality of soil, protection of surface waters and groundwaters, and compliance with concentration limits of heavy metals in soil. Use of biosolids is prohibited on specified categories of land within defined periods prior to harvesting and where concentrations of heavy metals in the soil exceed specified limit values. Records must be kept and made available to the competent authorities on the quantities, composition, use, treatment, and results of analysis on biosolids, the names and addresses of recipients of biosolids, and the places where biosolids are to be used (European Union 2000a). Accordingly, member states have performed biosolids surveys to comply with the reporting requirements, such as the U.K. Sludge Survey for 1996–1997 (Gendebien et al. 1999). Summary reports indicating biosolids quality and ultimate disposition quantities are to be submitted to the European Union every 5 years (e.g., UK. Department of the Environment 1993).

A part of the implementation of the directive is that application for biosolids use is made in advance of the operation, and conditions are applied to the methods and type of biosolids used. Consideration is given to the links between biosolids use and potential transmission of pathogens to the human food chain and into water courses or supplies through nutrient leaching. In addition, biosolids producers are obliged to provide details of biosolids composition to owners of land where biosolids will be applied (see Box 2–1). Analytical methods, sampling frequencies, monitoring procedures, and record-keeping requirements are also prescribed (see Box 2–2).

Proposed revisions are included in the European Union Working Document on Sludge (European Union 2000b), and changes in limit values are being considered for heavy metals and organic compounds on the basis of biosolids concentrations and soil characteristics. The use of biosolids in soils where the concentrations of heavy metals exceed the limit values suggested in Table 2–11 would be allowed only on a case-specific basis, and member states would have to ensure that those limit values are not exceeded as a result of the use of biosolids. If the concentrations of one or more heavy metals in biosolids are higher than the concentration limits suggested in Table 2–4 or if the concentrations of one or more organic compounds in biosolids are higher than the concentration limits proposed in Table 2–12, the use of biosolids

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

BOX 2–1 Examples of Regulatory Controls

One European Union member state (United Kingdom) operates a prenotification system through its competent authority. This system is designed to ensure that biosolids are given suitable treatment before spreading on agricultural land and has led to the setting of legal limits for metals in soil according to the requirements of the directive. In addition, the UK has set limits for 10-y average rates of application for metals in biosolids and requires that producers identify suitable sites. A code of practice for the agricultural use of biosolids in agriculture has been issued, and there is a separate code dealing with the agricultural use of biosolids in forests. The responsibility for undertaking sampling and analysis lies with the biosolids producers who must support their activities by maintaining records and supplying data to the Environment Ministry. Sampling and analytical procedures are in accordance with the code of practice, which incorporates the directive’s requirements and specifies restrictions to minimize risks to health.

The Sewage Sludge Directive has been incorporated into the legislation of another member state (Sweden) through an order issued by the Environment Ministry. This order governs the monitoring of biosolids quality and the spreading of biosolids on arable land. It also lays down limit values for inputs of nutrients to arable soil via biosolids, limit values for metals in arable soils, and limit values for inputs of metals to arable soil. A separate ordinance specifies limit values for metal concentrations in biosolids intended for agricultural use. Biosolids must be treated before being used in agriculture and producers of biosolids must supply a declaration of contents to those who will use the biosolids. Similarly, the operation of sewage plants in that state requires authorization from national and regional authorities.

In a third member state (Portugal) the national law sets limit values for heavy metal concentrations in the soil and the quantity of biosolids per hectare.

Source: Adapted from European Union 2000a.

should not take place. Compliance with Tables 2–4 and 2–12 is assumed if 90% of samples in a 12-month period are less than the standards and if 10% of samples exceed the standards by less than 50%. The maximum annual quantities of heavy metals indicated in Table 2–6 that may be added to the soil because of use of biosolids should not be exceeded. These limit values are intended to be reviewed every 6 years with a view toward achieving medium-and long-term concentrations for pollution prevention.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

BOX 2–2 Examples of Monitoring Procedures

In one member state (United Kingdom) monitoring is undertaken in accordance with the directive, whereby soil is analyzed on first application and at least every twentieth year while biosolids are spread to determine its pH and metals levels. Biosolids are analyzed at least every six months and every time significant changes occur in the quality of the biosolids treated at the works. Analysis is the responsibility of the biosolids producer but records must be kept and made available to the Environment Ministry. The analytical methods used are in accordance with the directive. The parameters analyzed conform to the directive and there are a number of additional ones.

In another member state (Portugal) the national law requires sampling of both the biosolids and the soil. The biosolids are analysed by the user, who has the burden of proof that it complies with the legally established limits. The results are then made available to the Institute of Waste (INR), Regional Directorates of the Environment (DRAs) or General Inspectorate of Environment (IGA), who give the final approval. The analyses of the soil are to be undertaken before biosolids are applied, although there is no specification of sampling frequency after the biosolids are spread. The results must be kept for five years.

In another member state (Sweden) the producer of biosolids is responsible for carrying out sampling and analysis of biosolids in respect of dry matter and loss on ignition; pH; total phosphorus; total nitrogen; ammonium nitrogen; lead, cadmium, copper, chromium, mercury, nickel and zinc. The order that requires this also lays down detailed rules on sampling and analysis methods. The frequency of sampling and analysis is determined according to the treatment capacity of the plant. As a minimum, the sampling and analysis must be done on an annual basis. Permitting authorities are responsible for supervision and inspection.

Source: Adapted from European Union 2000a.

PATHOGEN ISSUES AND TREATMENT CONTROLS

EPA sponsored the Workshop on Emerging Infectious Disease Agents and Issues Associated with Animal Manures, Biosolids, and Other Similar By-Products in Cincinnati, Ohio, in June 2001. This workshop was attended by over 100 participants from around the world, who raised general concerns with respect to bacteria, viruses, and parasites in these materials. Although animal manures are generally land applied and untreated and contain pathogens of concern, only biosolids are addressed in this report. Concerns for pathogen control in Classes A and B biosolids were expressed. For example, because Class B biosolids are only partially disinfected through treatment,

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–11 European Union Limit Values for Concentrations of Heavy Metals in Soil

 

Limit Values (mg/kg of DM)

Elements

Directive 86/278/EEC 6<pH<7

Proposed 5≤pH<6

Proposed 6≤pH<7

Proposed pH≥7

Cadmium

1–3

0.5

1

1.5

Chromium

-

30

60

100

Copper

50–140

20

50

100

Mercury

1–1.5

0.1

0.5

1

Nickel

30–75

15

50

70

Lead

50–300

70

70

100

Zinc

150–300

60

150

200

Note: When the concentration value of an element in a specific land area is higher than the concentration limit set in the table, the competent authority may still allow the use of biosolids on that land on a case-by-case basis after evaluation of the following aspects: (1) intake of heavy metals by animals, (2) uptake of heavy metals by plants, (3) groundwater contamination, and (4) long-term effects on biodiversity, particularly on soil biota. The areas of land with higher metal concentrations will be monitored and the possibility of using biosolids will be subject to a periodical assessment by the competent authority.

Abbreviation: DM, dry matter.

Source: Adapted from European Union 2000b.

further disinfection of land-applied Class B biosolids is related to management and treatment by natural attenuation. Workshop participants agreed that more data are needed on rates of pathogen survival in soil or on crops after application of biosolids. As discussed earlier, the criteria of at least seven samples with a geometric mean of less than 2×106 MPN or CPU of fecal coliform per gram of dry weight as a control is one of the means for determining Class B treatment adequacy. Better documentation is needed to correlate that or any number to treatment efficiency.

The process control requirements for Classes A and B designations are essentially identical to those established in 40 CFR 257, the 1979 regulations preceding 40 CFR 503. The treatment controls were based on an assumed log reduction of at least 1 for each option (EPA 1985, 1989). The fecal density requirement established in 40 CFR 503 was assumed to correlate to a roughly 2-log reduction (EPA 1985, 1992). However, as early as 1981, it was recognized that additional research was necessary to better document the presence of pathogens and other organisms in raw sewage sludge and their

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–12 Proposed Limit Values for Concentrations of Organic Compounds and Dioxins in Biosolids for Use on Land

Organic Compounds

Proposed Limit Values (mg/kg of DM)

AOXa

500

LASb

2,600

DEHPc

100

NPEd

50

PAHe

6

PCBf

0.8

Dioxins

Proposed Limit Values (ng TE/kg of DM)

PCDD/PCKFg

100

aSum of halogenated organic compounds.

bLinear alkylbenzene sulfonates.

cDi(2-ethylhexyl)phthalate.

dIt comprises the substances nonylphenol and nonylphenolethoxylates with 1 or 2 ethoxy groups.

eSum of the following polycyclic aromatic hydrocarbons: acenapthene, phenanthrene, fluorene, flouranthene, pyrene, benzo[b+j+k]fluoranthene, benzo[a]pyrene, benzo-[ghi]perylene, indeno[1,2,3-c,d]pyrene.

fSum of the polychlorinated biphenyl congeners number 28, 52, 101, 118, 138, 153, 180.

gPolychlorinated dibenzodioxins and dibenzofurans.

Abbreviations: DM, dry matter; TE, 2,3,7,8-tetrachloro-p-dioxin toxicity equivalents.

Source: Adapted from European Union 2000b.

fate through the various treatment regimes in the regulations, and a comprehensive literature review of all relevant publications between 1940 and 1980 was conducted (Pedersen 1981).

Based on limited analyses in EPA’s National Risk Management Research Laboratory (NRMRL) in Cincinnati and more complete data collected in Wisconsin between 1998 and 2000, fecal coliforms appear to be present at very low densities in biosolids and perhaps even in raw sewage sludge. That is also true of Ascaris eggs and enteric virus (J.Smith, EPA, personal communication, 2002; WDNR, unpublished data, 2000). These data raise the question of the validity of relying on numeric standards for various organisms because it is unclear what they represent. For example, enteric virus and helminth ova are used to measure treatment efficiency for Class A biosolids because of their hardiness and resistance to treatment, but they are also used as indicators of Class A treatment in alternatives 3 and 4 (discussed previ-

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

ously). Thus, numeric standards are not necessarily incorrect, but there is a need to better define their regulatory meaning and adequacy. Another point of concern raised at the EPA workshop was assay development. For example, with the measurement of Ascaris, there is no proper protocol for sampling, pretreatment, and purification before the assay and the appropriate quality-assurance and quality-control (QA and QC) protocols for the spike to be used in the assays. The assays for the other parasites and protozoan oocysts are also unreliable and underdeveloped. The analytical methods for other parasites, protozoan oocysts, and even fecal coliform in biosolids are also suspect, and method development and validation are needed (EPA 2001c). Table 2–13 provides a partial list of possible organisms that may be used as measures of treatment efficiency and that was discussed at the EPA 2001 conference.

Many organisms of concern have been known to be present in sewage sludge, and regulations have been developed with the intent to maximize their elimination and minimize the potential transport to humans. This was evident in the initial sewage sludge (40 CFR 257) regulations promulgated in 1979. Nevertheless, new organisms of concern have been identified, and new research should be initiated to reconfirm the level of disinfection achieved through various pathogen process controls. Bacteria such as E. coli 0157:H7, Listeria, and Helicobacter have emerged as potential public-health problems (see Chapter 6 for more details). Table 2–14 lists these and other bacteria of potential regulatory concern, including ones that represent a change in concern from low to high or are newly recognized. In addition, it is necessary to understand the mechanisms responsible for pathogen reduction and time required to meet the control-process requirements. For these reasons, it is necessary to validate the rate of elimination of pathogens through various treatment regimes. Research in this area is currently underway (J.Smith, EPA, personal communication, May 2002).

In the area of virology, the conference raised several issues concerning viruses, such as coxsackievirus, echovirus, adenoviruses, rotaviruses, and reovirus (to name a few). Their potential impact on public health is included in Table 2–15. For pathogen monitoring, the virologists discussed using enteroviruses and coliphages for process disinfection efficacy, but suggested E. coli, fecal coliforms, enterococci, and Clostridium perfringens for field monitoring. As a result of the workshop deliberations, the consensus opinion of the participating virologists was that Class-B-treatment processes should yield the reductions summarized in Table 2–16 if the processes are properly conducted and maintained and the site’s climate, geology, and soil characteristics enable natural attenuation.

Regarding the assessment of helminth eggs and protozoan oocysts, the efficacy of existing Class B disinfection processes for inactivating parasites

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–13 Process Criteria for Class B Biosolids

Bacterial Inactivation

Process

Temperature

Critical Parameter

Time

Possible Measure of Efficiency

Air drying

>0­°C

Desiccation by-products

2–3 mo

E. coli, fecal coliform, Clostridium perfringens

Alkaline stabilization

Ambient

Ammonia, pH

2 h

Clostridium perfringens

Aerobic digestion

15–20­°C

Endogenous microbial activity

60–40 d

Fecal coliform, E. coli

Anaerobic digestion

20–35­°C

Endogenous microbial activity, organic by-products

60–15 d

Clostridium perfringens

Composting

40–55­°C

Organic by-products

5 d at 40­°C, 4 h at 55­°C

Clostridium perfringens

 

Source: EPA 2001c.

remains a concern, but the processes should be effective for protozoan oocysts. However, little information is available on treatment efficiency of helminth eggs. There are also concerns with analytical methods for the detection and identification of helminth eggs of the species noted in Table 2–17. Therefore, research is needed to develop reliable assays to measure helminth eggs and to assess the efficacy of Class B processes for inactivating helminths (e.g., Taenia and Toxicara) where fecal coliforms have traditionally been the only means of monitoring pathogen-inactivation performance. The workshop participants expressed interest in using Clostridium perfringens as an indicator organism when noncharged biocides are the major agent for inactivation and for anaerobic digestion, lagoon storage, composting, and alkaline stabilization. The existing Part 503 regulation states that the Class A disinfected biosolids are far less a concern as a result of Ascaris egg controls along with the temperature factors. In the current Class A requirements, monitoring is required for Salmonella or fecal coliform in addition to meeting one of several treatment control processes, which include several nationally approved processes designated equivalent to a process to further reduce pathogens (PFRP) (listed in Table 2–18).

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–14 Bacterial Pathogens of Potential Concern in Biosolids

Major Concern—Classica

New Issues—Changesb

Salmonella

E. coli 0157:H7

Shigella

Listeria

Enteropathogenic E. coli

Helicobacter

Yersinia enterocolitica

Mycobacteria

Campylobacter jejuni

Aeromonas

Vibrio cholera

Legionella

Leptospira

Burkholderia

 

Endotoxins

 

Antibiotic resistance

aKowal 1985.

bEPA 2001c.

Concerns for Class A processes were also elucidated at the EPA workshop. However, there was less concern with pathogen contamination and more with the confirmation of the efficiency of Class A processes. (Approved mechanisms of pathogen control for Class A treatment for bacteria, viruses, and parasites are summarized in Table 2–19.) Issues of concern included regrowth of pathogens with short-term stabilized biosolids and possible emission of odors. Others were specification of treatment process versus product control and the appropriate point in the treatment process to obtain pre-treatment samples and whether to use an indicator organism to predict pathogen survival and recontamination. However, the major problem discussed at the workshop was the Class A process criteria that do not take into account potentials for regrowth. Regrowth of pathogens can occur in Class A biosolids but generally not in Class B biosolids. To prevent pathogen regrowth, a fairly stable background population of microorganisms is needed. Relevant research on composting indicates the need for 104 to 105 microorganisms per gram of dry weight of solid (Burnham et al. 1992). With such background levels, as would be common with Class B biosolids, pathogen regrowth is inhibited by competition with the existing microbial ecosystem. Class A disinfection processes generally eliminate these competing microorganisms, requiring retesting of Class A biosolids if used in bulk quantities more than 3 weeks or so after production.

Bioaerosol generation is a concern with the processes of aerobic digestion, anaerobic digestion, composting, alkaline stabilization, and combinations. The

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–15 Principal Viruses of Concern in Municipal Wastewater and Sewage Sludge

Virus

Diseases of Public Health Concern

Poliovirus

Poliomyelitis

Coxsackievirus

Meningitis, pneumonia, hepatitis, fever, etc.

Echovirus

Meningitis, paralysis, encephalitis, fever, etc.

Hepatitis A virus

Infectious hepatitis

Rotavirus

Acute gastroenteritis with sever diarrhea

Norwalk agents

Epidemic gastroenteritis with severe diarrhea

Reovirus

Respiratory infections, gastroenteritis

 

Source: Kowal 1985.

concerns are bacterial species, viruses, and bacteria in bioaerosols but probably not parasites due to their greater size and weight.

In summary, several pathogen-related issues and research needs were identified at the EPA workshop and in related literature:

  • Further information regarding pathogen survival in processing or emission during the process.

  • Research on vectors carrying pathogens and toxins.

  • Assessment of bioaerosols and other chemical aerosols.

  • Test-method development and validation for various organisms in sewage sludge and biosolids.

  • Field verification of efficacy of Class A and Class B treatment processes (including data to directly relate process controls to initial and final pathogen and indicator densities).

  • Development of indicator pathogens for assessment of impact and attenuation in field situations.

PATHOGEN EQUIVALENCY COMMITTEE

A critical function in the regulation of sewage sludge and biosolids is fulfilled by the Pathogen Equivalency Committee (PEC) established in 1985. The PEC is composed of experts within EPA, who evaluate treatment technologies to determine whether they are equivalent in treatment efficiency to either recognized PSRP (Class B) or PFRP (Class A) as defined in 40 CFR

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–16 Class B Virus Reduction for Biosolids Disinfection Process

Process

Virus Log Reduction

Time

Lagoon storage

1–2

6–12 mo

Mesophilic anaerobic digestion

1–2

15–30 d

Mesophilic aerobic digestion

1–2

15–30 d

Alkaline stabilization

pH=11 to 12

1–3

1 d

Air drying <3% solids

<1

2–3 mo

Air drying >3% solids

3–4

2–3 mo

Heat drying 55–60°C

3–4

~1 h

Composting 40–55°C

3–4

6 wk

 

Source: EPA 2001c.

503. Determination of several such treatment technologies expected within a few years are vermicomposting, microwave technology, infrared irradiation technology, alkaline stabilization, anaerobic digestion, and aerobic digestion. The equivalency criteria could be related to treatment alternatives 1 through 6 for Class A or alternatives 1 through 3 for Class B.

The long-term responsibilities of PEC include integrating and developing methods for microbial assays, gross biosolids parameters, analysis of metals, and analytical techniques for organics, many of which are included in Standard Methods, manuals published by the American Society for Testing and Materials, and agricultural analyses. In developing microbial assays, protocol development and workshops to train EPA and other professionals are needed. The same issues relate to vector-attraction tests, which need to be compiled and refined for new stabilization techniques. Due to the major problems arising with manure in nonpoint source pollution, USDA and EPA should collaborate on method development. However, EPA does not have a formal coordinated group that handles these important issues, and there has been no logical protocol to resolve these questions. Even so, the committee believes that this ongoing problem could be resolved with appropriate action from EPA.

In the fall of 2000, Haas (2001) conducted an independent assessment of the pathogen equivalency process. That report focused on the determination of equivalency for both PSRP and PFRP process assessment. Overall, the report found that the members of the PEC need assistance to better conduct their duties. The report’s short-term recommendations to support the PEC were as follow:

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–17 Principal Parasites of Concern in Municipal Wastewater and Sewage Sludge

Helminth Worms

Symptoms or Diseases

Ascaris lumbricoides

Digestive disturbances, abdominal pain

Ascaris suum

Coughing, chest pain, or asymptomatic

Trichuris trichiura

Abdominal pain, diarrhea, anemia, weight loss

Toxocara canis

Fever, abdominal discomfort, and muscle aches

Taenia sasginata

Nervousness, insomnia, anorexia

Taenia solium

Nervousness, insomnia, anorexia

Necator americanus

Hookworm disease

Hymenolepis nana

Taeniasis

 

Source: Kowal 1985.

  • The PEC members should have a formal portion of their time allocated to PEC responsibilities.

  • Travel funds should be put at the disposal of the PEC to enable meeting attendance and visits to selected sites of petitioners.

  • There is a perception on the part of PEC members that EPA’s Cincinnati laboratories do not include biosolids as a formal part of their mission statement. This needs to be clarified and rectified.

  • A formal procedure for designation of backup members should be devised.

The report also included a protocol for formally handling a PEC application and recommended that it be developed via a formal approval route. Overall, the report found that the diverse background of EPA staff serving on the PEC is a well-rounded forum and should be continued.

IMPLEMENTATION AND END-USE PRACTICES

Overview

There are three major alternatives for final disposition of sewage sludge: (1) recycling as biosolids to agricultural land as a fertilizer or soil amendment or selling or giving away to the public for use on home gardens or lawns; (2)

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–18 Processes Recommended as Equivalent to PFRP

Process

Criteria for Approval

CBI Walker, Inc.

Aurora, Illinois

Two-stage aerobic digestion process utilized time-temperature control with resulting mesophilic aerobic digestion for stabilization

Fuchs Gass and Wasserteckink

Mayen, Germany

Two-stage autothermophilic aerobic digestion process utilizing time-temperature control with resulting mesophilic aerobic digestion for stabilization.

International Process Systems, Inc.

Glastonbay, Connecticut

In-vessel composting process related to time-temperature disinfection followed by compost maturation for stabilization

K-F Environmental Technologies, Inc.

Pompton Plains, New Jersey

Indirect drying process utilizing the PSRP (process to significantly reduce pathogens) heat drying process criteria and short-term stabilization at less than 10% moisture content

Lyonnaise des Eaux

Pecz-Sur-Seine, France

Two-phase thermophillic and mesophilic anaerobic digestion where pathogen criteria used to demonstrate PFRP (process for the further reduction of pathogens) criteria with mesophilic stabilization

AJW, Inc.

Santa Barbara, California

Thermophilic alkaline stabilization used pasteurization criteria with short-term stabilization related by pH.

N-Viro

Toledo, Ohio

Advance alkaline stabilization that has various alternatives for disinfection and alkaline composting for disinfection. They used the pathogen criteria and alternative 2.

Synox Corporation

Jacksonville, Floride

OxyOzonation process is an acid-oxidizing process that utilizes a pathogen criteria from influent and effluent in alternative 3

Ultra Clear, Inc.

Marlboro, New Jersey

Microbiological composting and drying process which is a time-temperature process equivalency

 

Source: EPA 1999b.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–19 Class A Inactivation of Pathogens

Process

Inactivation

Concerns

Aerobic digestion

(thermophilic)

Time, temperature

Oxygen transfer, solids content, bioaerosols

Anaerobic digestion

(thermophilic)

By-products, time, temperature

Solids content, odor, bioaerosols, pH

Composting

(thermophilic)

By Products, time, temperature

Solids content, odor, bioaerosols, pH

Alkaline stabilization

Ammonia, time-temperature

Solids content, odor, aerosols, pH

Heat drying

(>80°C)

Time-temperature

Explosions, odors, aerosols

Irradiation

(gamma, beta)

>1 megarad

Solids content, stablization

Combinations

Digestors

Lagoons

Drying beds

Time-temperature, by-products

Solids content, odors, bioaerosols

 

Sources: Reimers et al. 1986a,b, 1999, 2001; EPA 2001c.

burying in a municipal solid-waste landfill or a surface disposal site; or (3) burning in an incinerator. When assessing any of these practices, they should be evaluated holistically for risk. For instance, if all land application should cease, how would the overall risk be altered if additional landfills, surface disposal sites, and incinerators were constructed and operated to accommodate the additional volumes? In response to EPA’s beneficial-use policy, the publication of risk-based regulations and the general trend toward recycling, numerous states began to encourage POTWs to use their biosolids in the late 1980s and 1990s. This policy was further aided by philosophical shifts away from and political and legal difficulties associated with siting and constructing incinerators and landfills.

Management Practices

Biosolids are applied to land through one of three methods:

  • Injection: Injection vehicles directly inject liquid biosolids at a depth of 6 to 9 inches into the soil. The injectors may simultaneously disc the field

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

or include fine injection tubes for minimal soil breakup, depending on the type of farm-management practices used. This method is considered the most effective for odor control and minimizes the risk of runoff to surface waters. However, it is not possible to use injection when applying to hay crops or frozen ground. Application is usually prior to planting or after harvest. Vehicles range from 1,500- to 5,000-gallon capacity. Injection is considered a physical-barrier option for satisfying vector-control requirements.

  • Incorporation: Biosolids are applied to the surface of the soil and then physically worked into the field within 6 h or as specified by the permit authority. This method is common for cake solids that cannot be injected and is used either prior to planting or after harvest. Biosolids are generally incorporated at a depth of 6 to 9 inches. Incorporation is also considered a physical-barrier option for satisfying vector-control requirements.

  • Surface Application: Either liquid or cake solids are applied to the soil surface but are not incorporated into the soil until normal farming practices disturb the soil. This method is common for hay crops and application during winter months. Surface application does not satisfy vector-control requirements, and stabilization must be accomplished through treatment prior to surface application.

The federal regulations for managing a land-application site include the following prescriptions:

  • Biosolids shall not be applied to land if it is likely to adversely affect a threatened or endangered species or its critical habitat.

  • Biosolids must not be applied to land that is frozen, flooded, or snow covered, so that biosolids cannot enter any wetland or waters of the United States, except as provided in an National Pollutant Discharge Elimination System (NPDES) permit.

  • Biosolids must not be applied to land at a distance of less than 10 meters (33 feet) from any waters of the United States, unless otherwise specified in a NPDES permit.

  • Biosolids must be applied at a rate equal to or less than the agronomic nitrogen need of the crop to be grown.

Some states require more stringent site criteria, including greater distances from surface waters, maximum slope restrictions, minimum depths to groundwater and bedrock, minimum and maximum soil permeability rates, minimum distances to residences or recreation areas, and minimum distances to private or public water-supply wells. For example, Table 2–20 compares the criteria required by Wisconsin with those of the Part 503 rule.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–20 Wisconsin Requirements for Biosolids Applied to the Land in Bulk

Site Criteria

Surface

Incorporation

Injection

Part 503 Requirements

Depth to bedrock

3 ft

3 ft

3 ft

 

Depth to high groundwater

3 ft

3 ft

3 ft

Allowable slopes

0–6%

0–12%

0–12%

Distance to wells

- Community water supply or school

1000 ft

1000 ft

1000 ft

 

- Othera

250 ft

250 fta

250 fta

Minimum distance to residence, business or recreation area

500 ft

200 ft

200 ft

Minimum distance to residence or business with permission

250 ft

100 ft

100 ft

Distance to rural schools and health care facilities

1000 ft

1000 ft

500 ft

Distance to property line

50 ftb

25 ftb

25 ftb

Minimum distance to streams, lakes, ponds, wetlands, or channelized waterways connected to a stream, lake, or wetland

 

33 ft

- Slope 0 to <6 %

200 ft

150 ft

100 ft

 

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

- Slope 6 to <12 %

Not allowed

200 ft

150 ft

Minimum distance to grass waterways, or dry run with a 50 ft range grass stripc

- Slope 0 to <6 %

100 ft

50 ft

25 ft

- Slope 6 to <12 %

Not allowed

100 ft

50 ft

Soil permeability range (in/h)

0.2–6.0

0–6.0

0–6.0

aSeparation distances to nonpotable wells used for irrigation or monitoring may be reduced to 50 ft. if the biosolids are incorporated or injected and the department does not determine that a greater distance to the wells is required to protect the groundwater.

bThe distances to property lines may be reduced with the written permission of both property owners.

cReparation distances not required if grass waterway or dry run with grass strip is contained within a site or field for the purpose of erosion control.

Source: Adapted from Wisconsin Administrative Code 1996.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Inherent in the concept of developing two classes of pathogen-control criteria are management-practices and site-restriction requirements to equalize the two standards. EPA imposed limitations regarding minimum time durations between application of Class B biosolids and the harvesting of certain crops, the grazing of animals, and public access to the site. Those limitations are summarized in Table 2–21. If the limitations are followed, EPA concluded that the level of protection from pathogenic organisms in Class B biosolids was equal to the protection provided by the unregulated use of Class A biosolids.

Three factors affect the potential dietary exposure to pathogens via crops through land application (EPA 1999b): (1) pathogens must be in the biosolids; (2) the application of biosolids to food crops must transfer the pathogens to the harvested crop; and (3) the crop must be ingested before it is processed to reduce the pathogens. If all three factors are not present, potential exposure is eliminated. The production of Class A biosolids reduces the pathogens in biosolids to below detectable concentrations and may be used without further restriction if it is also deemed exceptional quality (EQ). In contrast, Class B biosolids may contain reduced but still measurable densities of pathogenic bacteria, viruses, protozoans, and viable helminth ova.

The site restrictions are imposed to allow for further reduction of the pathogenic populations through natural attenuation processes. The restrictions are based primarily on the survival rate of helminth ova, which are considered the hardiest pathogens that might be present in biosolids. Some of the factors that influence pathogen survival are sunlight, moisture, pH, temperature, cations, presence of soil microflora, and organic material content. Potential pathways of exposure are also considered in setting the time restrictions. For instance, pathogen die-off is much different when crops are exposed on their surfaces compared with crops grown underground. Helminth ova can survive on top of soil or within soil for months to years depending on climate; thus, longer waiting periods are required for food crops either grown in the biosolids-amended soil or in contact with the soil-biosolids mixture. In practice, far less than 1% of biosolids-amended land is used for the production of unprocessed food-chain crops (WDNR, unpublished data, 2001). Of 27 states responding to an inquiry on this topic by the Wisconsin Department of Natural Resources (WDNR), 25 reported no such use and two reported less than 1% such use. Based on these results, this finding can be reasonably expected in the remaining 23 states.

Other management practices are intended to minimize the introduction of biosolids to surface water (primarily because of phosphorus and solids concerns) or the leaching of biosolids to groundwater (primarily because of nitrate concerns). To this end, for Class B and other non-EQ biosolids, EPA

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–21 Minimum Duration Between Application and Harvest/Grazing/Access forClass B Biosolids Applied to the Land

Criteria

Surface

Incorporation

Injection

Food crops whose harvested part may touch the soil/biosolids mixture (beans, melons, squash, etc.)

14 mo

14 mo

14 mo

Food crops whose harvested parts grow in the soil (potatoes, carrots, etc.)

20/38 moa

38 mo

38 mo

Food, feed, and fiber crops (field corn, hay, sweet corn, etc.)

30 d

30 d

30 d

Grazing of animals

30 d

30 d

30 d

Public access restriction

High potentialb

1 y

1 y

1 y

Low potential

30 d

30 d

30 d

aThe 20 month duration between application and harvesting applies when the biosolids that are surface applied stays on the surface for 4 months or longer prior to incorporation into the soil. The 38 month duration is in effect when the biosolids remain on the surface for less than 4 months prior to incorporation.

bThis includes application to turf farms which place turf on land with a high potential for public exposure.

Source: Adapted from 40 CFR Part 503.

requires minimum setback distances of 10 meters from surface waters, although at least 21 states have increased their minimum setback distance between 50 and 300 feet. Such factors as slope, buffer strips, method of biosolids application, and the designated uses of nearby surface waters may be considered by states in setting setback distances. EPA also requires that application of non-EQ biosolids be limited to accommodate the nitrogen requirements of the crop to be grown. Notably, federal statutes do not include groundwater in the definition of waters of the United States, and thus no minimum depth to groundwater or bedrock is included in federal regulations. However, at least 23 states include such requirements and at least 10 have prohibited land application of biosolids during winter months. While recognizing that there are vast differences in topography, weather, and soil conditions across the country, EPA would be well advised to include more specific site requirements in its biosolids regulations, including minimum depth to groundwater, controls on winter application, and setback distances from residences.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

In addition, stockpiling of biosolids in fields should only be done with fully stabilized and treated biosolids, for very short durations (generally for no more than 72 h), and in a manner that ensures there is no runoff to surface water or adjacent land. Storage at treatment plants or off-site engineered facilities should be considered to avoid the need to land apply during inclement weather conditions.

Most states mimic the federal requirements for limiting land-application rates to accommodate the nitrogen requirements of the intended crops. Nitrogen is the limiting factor in assessing application rates. The application rate must be based on the nitrogen needs of the crop to be grown. Available nitrogen should be assessed based on mineralization rates for the organic nitrogen and method of application for the ammonium-nitrogen. Nitrogen supplied from all other sources must also be taken into account. This should be implemented through communication between the land applier and the farmer. Because of these nitrogen limitations, biosolids are the most regulated fertilizer or soil amendment used on agricultural land. However, a small but growing number of states are also limiting the application rate based on the phosphorus needs of the crop or some other phosphorus index. As animal waste becomes further regulated based on phosphorus content, phosphorus consideration is likely to have an impact on the biosolids program as well. (Animal waste has not to date been regulated to address pathogen or nutrient control.) Excess phosphorus often becomes a water-quality problem after it reaches surface waters, because it promotes accelerated algae growth and eutrophication. For these reasons, wastewater treatment plants are increasingly being forced to limit the phosphorus in their effluent discharge to surface waters. Therefore, the phosphorus concentration in sewage sludge is necessarily increasing. Although the Part 503 rule does not address phosphorus, many states require setback distances, slope restrictions, and winter prohibitions to minimize the potential for runoff and the associated problems with phosphorus.

End-Use Practices

The WDNR has worked with all states to gain information regarding biosolids-use practices, quality, pathogen control, and vector-attraction reduction. The following data from 37 states represent the best estimation of current biosolids use in the United States (WDNR, unpublished data, 2001):

  • 5.6 million dry tons of biosolids are used or disposed of.

  • Of that, 3.4 million dry tons of biosolids are used as soil amendments

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

and/or fertilizer in the United States, representing 61% of the total amount used or disposed of.

  • 2.4 million dry tons of biosolids are land applied, representing 43% of the total amount used or disposed of.

  • 1 million dry tons of biosolids are land applied or publicly distributed as EQ biosolids, representing 18% of the total amount used or disposed of.

  • 0.95 million dry tons of biosolids are disposed of in licensed municipal solid waste landfills, representing 17% of the total amount used or disposed of.

  • 0.08 million dry tons of biosolids are disposed of in surface disposal units, representing 1% of the total amount used or disposed of.

  • 1.1 million dry tons of biosolids are burned through incineration, representing 20% of the total amount used or disposed of.

CHARACTERIZATION OF BIOSOLIDS

Several national surveys of biosolids quality have been conducted by EPA and the Association of Metropolitan Sewerage Agencies (AMSA) to quantify concentrations of pollutants and nutrients in biosolids. In addition, states have collected data on biosolids as part of their biosolids program management and compliance monitoring for many years. Compliance is tracked largely through state programs and through the federal Biosolids Data Management System (BDMS) and Permit Compliance System (PCS). For chemicals, monitoring is required for total percent solids, the nine regulated inorganic compounds, total nitrogen, and total nitrogen ammonium. For pathogens, the pathogen density requirements for Class A and Class B biosolids (discussed earlier in this chapter) are monitored. Vector attraction reduction requirements are also monitored. Minimum monitoring requirements are specified in 40 CFR 503 based on the quantity of biosolids used or disposed of (see Table 2–22).

The current Part 503 regulations require that monitored biosolids must be representative of what is actually going to be used or disposed of. Whenever the biosolids are changed so that their characteristics change, new sampling must take place.

The success of the pretreatment program is illustrated in the reduced concentrations of selected inorganic pollutants in biosolids since the implementation of regulations on nondomestic discharges to sewerage systems. The data for biosolids show significant reductions in some of the regulated inorganic chemicals from the inception of the pretreatment program until the

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–22 Frequency of Monitoring and Land Application and Landfilling

Amount of Biosolids (dry metric tons per 365 days)

Amount of Biosolids (dry U.S. tons per 365 days)a

Frequency of Monitoring

0<X<290

0<X<320

Once per y

290≤X<1,500

320≤X<1,654

Once per quarter

1,500≤X<15,000

1,654≤X<16,540

Once per 60 d

15,000≤X

16,540≤X

Once per mo

aAmount that is land applied or landfilled on a dry weight basis.

bMetric tons=U.S. tons×0.907.

Source: 40 CFR 503.

mid-1990s when the concentrations leveled off. For example, data collected in Pennsylvania from 1978 to 1997 showed large decreases in cadmium, copper, lead, mercury, nickel, and zinc, and smaller rates of decreases for arsenic, selenium, and molybdenum (Stehouwer et al. 2000). Wisconsin and New Jersey have extensive biosolids monitoring data, and will be used for illustrative purposes. Tables 2–23 and 2–24 show pollutant concentrations over time. The numbers presented are state averages. The Wisconsin data include any outlier data, and nondetects are considered at the detection limit. Data from Portland, Oregon (Portland 2002), Seattle metropolitan area (King County 2000), and Milwaukee metropolitan area (MMSD 2001) depict similar trends.

In addition to the regulated pollutants within EPA’s biosolids program, the pretreatment program is charged with controlling the 126 “priority pollutants,” as well as any other incompatible pollutants from industries that discharge into the sewer systems, as described in the Clean Water Act (EPA 1999a). There are four criteria under the pretreatment program as described earlier. Those criteria are directed towards ensuring compliance with permits. Selected contaminants in their wastewater are monitored by industries to which the pretreatment program or local ordinance limits apply and also in the effluent discharge of the POTWs covered by the pretreatment program. Toxic organic chemicals discharged to a POTW may be volatilized, degraded, deposited in the sewage sludge or passed through to the effluent. Monitoring of the wastewater effluent may be required for the 126 priority pollutants, but there is no federal requirement to test sewage sludge for them, nor federal limits on most of their concentration in biosolids. One issue with monitoring for these constituents is that on the rare occasion that one or more of them are detected, there are no established criteria levels of concern for many of them. Reliable data on the impact of pretreatment programs on the concentration of toxic organic chemicals in biosolids are not currently available.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–23 Wisconsin Data (all values are in milligrams per kilogram of dry weight)

Element

1979

1982

1985

1988

1991

1994

1997

2000

As

17.4

6.5

6.0

8.4

9.1

7.4

9.8

11.2

Cd

23.7

18.8

28.8

17.7

11.2

7.2

6.3

6.0

Cr

1,053

699

777

363

247

117

73

89

Cu

821

792

873

702

586

573

575

540

Pb

326

310

248

182

130

95

77

63

Hg

3.4

5.2

8.2

4.2

3.9

3.8

2.6

3.4

Mo

 

36

22

21

20

Ni

131

130

92

83

52

41

43

36

Se

 

4.5

5.5

8.6

10.9

Zn

1,881

2,045

1,631

1,360

1,054

921

892

847

 

Source: WDNR, unpublished data, 2001

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

TABLE 2–24 New Jersey Data (all values are in milligram per kilogram of dry weight)

Element

1981–1983

1989–1994

1997

As

2.7

2.85

4.33

Cd

9.4

5.6

3.5

Cr

93

39

26

Cu

825

679

628

Pb

210

100

65

Hg

3.6

2.3

1.9

Mo

 

15

13

Ni

46

31

23

Se

 

2.0

4.9

Zn

1110

826

810

 

Source: New Jersey Department of Environmental Protection, unpublished data, 2001.

PCBs were considered a group of related organic compounds in the initial development of the Part 503 regulations but ultimately were not regulated because their production had already been banned in the United States. However, 12 coplanar PCBs are still under consideration for regulation in Part 503. A 2000 survey of 50 biosolids samples in Wisconsin found detected concentrations of total PCBs in 40% of the samples when the analysis was performed on an aroclor basis (WDNR, unpublished material, 2000). A further analysis of a subset of the 50 samples (samples with detectable aroclors, six with nondetectable aroclor samples, and one resample) on a congener-specific basis found detectable concentrations in 100% of the samples. A similar 2001 EPA survey of 101 biosolids samples from across the nation also found detectable concentrations of coplanar PCBs (EPA 2002a). The total PCB concentration mean in the Wisconsin survey was 0.23 mg/kg for the aroclor analyses and 0.3 mg/kg for the congener-specific analyses. Current regulations in 40 CFR 761 state that land-applied biosolids with concentrations of total PCBs at less than 50 mg/kg are regulated under 40 CFR 503, and sewage sludge with concentrations greater than 50 mg/kg cannot be land applied and is subject to provisions within that regulation (EPA 1998). Furthermore, 40 CFR 257 requires industrial sludge with concentrations of total PCBs at greater than 10 mg/kg to be injected or incorporated when land applied.

EPA’s stated purpose in their sampling survey of 2001 was to determine toxicity equivalent concentrations (TEQs) for the 29 congeners of dioxins,

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

furans, and coplanar PCBs, which they proposed to add to 40 CFR 503. The mean TEQ value for total dioxin and dioxin-like compounds was 31.60 nanograms per kilogram (ng/kg) DM, when nondetect measurements were summed at one-half the detection limit (EPA 2002a). AMSA also conducted a survey of member and nonmember facilities in late 2000 (Alvarado et al. 2001). A total of 197 biosolids samples were collected from 170 facilities and mean and median TEQ concentrations of 48.5 and 21.7 ng/kg were reported, respectively. The TEQ values ranged from 7.1 to 256 ng/kg with a single outlier of 3,590 ng/kg. Notably, these TEQ concentrations are lower than those reported in a similar survey conducted in 1994 (Green et al. 1995). This finding may be due to fewer medical-waste incinerators in operation and other reduced combustion sources of dioxin but may in large part be explained by improved analytical techniques. In all three surveys, nondetectable congeners were summed at one-half the detection concentration. As detection concentrations continue to decrease, so too do the added values of nondetections.

The State of Vermont recently reported the results of a survey of the 17 dioxin and furan congeners (but excluded coplanar PCBs) in a sampling of 20 POTWs and 3 comingling EQ generating facilities (Kelley 2000). A total of 28 samples were collected in November and December 1996 and in August 1998. The mean and median TEQ concentrations were 11.22 and 8.55 ppt, respectively, and the range was from 1.32 to 59.44 ppt. One important difference in the Vermont survey data compared with the EPA and AMSA data is that nondetectable congeners were summed as zero rather than one-half the detection limit.

COMPLIANCE ASSISTANCE AND ENFORCEMENT

Perhaps the most common and vocal complaint of EPA’s biosolids program is the lack of federal presence to ensure compliance with the existing regulations. In the absence of that assurance, and as the report of the Office of the Inspector General (OIG) concluded (EPA 2000b), EPA cannot claim that the regulations are followed and that public health and the environment are protected as required by the CWA. States do, however, implement their own biosolids programs to some greater or lesser extent and actively participate in both compliance assistance and enforcement.

State regulators report substantial compliance is prevalent when assessed. EPA’s Office of Enforcement and Compliance Assistance has taken a formal position that biosolids are a low public-health and environmental priority, and thus no formal program policy is in place. However, according to EPA, all 10 regional offices will take appropriate action as required if a case is brought to their attention (D.Regas, EPA, personal communication to OIG, June 11,

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

2001). Although some EPA regional offices are more aggressive and involved than others, little enforcement action is taken at the federal level. Furthermore, enforcement strategies differ between states and EPA; states tend to favor stepped enforcement that focuses on compliance assistance and education, and EPA is likely to levy monetary penalties with less discussion.

EPA recently established an incident-response team, as part of the Biosolids Program Implementation Team, to address and investigate critical allegations of sewage sludge and biosolids violations and public-health threats. A problem this team has faced is that they are not notified of situations in a timely manner. There is currently no process for registration or follow-up on complaints and alleged violations. An administrative framework is necessary to track such allegations, investigations, and outcomes.

FINDINGS AND RECOMMENDATIONS

EPA provides insufficient support and oversight to the biosolids program. EPA gives low priority to its biosolids program, because it contends that risks from exposure to chemicals and pathogens in biosolids are low and that land-application programs generally function as intended and in compliance with the regulations. This contention should be better substantiated.

Recommendations

  • EPA should strengthen its biosolids-oversight program by increasing the amount of funding and staff (technical and administrative) devoted to it.

  • EPA should provide additional funds (not diverted funds) to states to implement biosolids programs and facilitate delegation of authority to states to administer the federal biosolids regulations.

  • Resources are also needed for conducting research into emerging issues and to revise the regulations as appropriate and in a timely fashion (e.g., molybdenum standards should be proposed).

  • A process should be established to track allegations and sentinel events (compliance, management, or health based), investigations, and conclusions. Such tracking should be systematic, developed in cooperation with states, and should document both positive and negative outcomes.

The Pathogen Equivalency Committee (PEC) performs invaluable technical support and process assessment.

Recommendations

  • The PEC should be funded, supported, and officially sanctioned as an integral part of the federal biosolids program. The following are important in supporting the PEC:

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • The PEC members should have a formal portion of their time allocated to PEC responsibilities.

  • Travel funds should be put at the disposal of the PEC to enable meeting attendance and visits to selected sites of petitioners.

  • There is a perception on the part of PEC members that EPA’s Cincinnati laboratories do not include biosolids as a formal part of their mission statement. This needs to be clarified and rectified.

  • formal procedure for designation of backup members should be devised.

Biosolids risk-management practices are an integral component of the risk assessment and technological criteria that were used to establish the standards of the Part 503 rule. They are therefore an important component of the regulations for chemicals and pathogens.

Recommendations

  • Studies should be conducted to determine whether the management practices specified in the Part 503 rule (e.g., 10-meter setback from waters) achieve their intended effect.

  • Additional risk-management practices should be considered in future revisions to the Part 503 rule, including setbacks from residences or businesses, setbacks from private and public water-supply wells, slope restrictions, soil permeability and depth to groundwater or bedrock, and reexamination of whether a greater setback distance to surface water is warranted.

  • Provisions for allowing distribution of Class A biosolids in bags or other containers (weighing less than 1 metric ton) should not be allowed when they do not meet pollutant concentration limits (i.e., all biosolids sold or given away should be EQ).

  • Exemptions from nutrient management and site restrictions for land application of bulk EQ biosolids should be eliminated.

There are several prescribed treatment processes that can be used to meet regulatory requirements for classifying biosolids as Class A or Class B. However, the efficacy of the treatment processes needs verification, and the stabilization regulations need to be refined for consistent control of vector attraction.

Recommendations

  • EPA should conduct national field and laboratory surveys to verify that Class A and Class B treatment processes perform as assumed by their engineering and design principles. Determinations should be made of pathogen density and elimination across the various accepted treatment processes and in the biosolids or environmental media over time.

  • Standard treatment design criteria should be adopted nationally to ensure compliance with existing biosolids regulations.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • Stabilization controls need to be further refined and directly correlated to metabolic techniques (e.g., SOUR test, carbon dioxide metabolic release, methane metabolic release).

The available methods for detecting and quantifying pathogens in biosolids have not been validated. There have been a number of advances in detection and quantification of pathogens in the environment and in approaches to environmental sample collection and processing. However, no consensus standards have been developed for pathogen measurements in biosolids.

Recommendation

EPA should support development, standardization, and validation of detection and quantification methods for pathogens and indicator organisms regulated under the Part 503 rule. The sufficiency of these methods and their results should be considered in conducting and interpreting future risk assessments and used to develop applicable risk-management technologies.

The CWA requires EPA to establish biosolids regulations based on risk; however, it is important to acknowledge and consider other approaches to regulating land application of biosolids.

Recommendation

As part of the process of revising the Part 503 rule, EPA should review biosolids protocols used by other nations. This could provide valuable new perspectives and insights into the scientific, technical, and societal bases for the development and implementation of biosolids regulations.

EPA and the U.S. Department of Agriculture cosponsored a workshop on emerging pathogens in June 2001 with international experts in the field. The committee supports the major research recommendations from that workshop (listed below).

Recommendations

Research is needed on the following topics:

  • Pathogen survival in processing or emissions during the treatment process.

  • Vectors carrying pathogens and toxins.

  • Bioaerosols and other chemical aerosols.

  • Test-method development and validation for various organisms in sewage sludge and biosolids.

  • Field verification of efficacy of Class A and Class B treatment processes (including data to directly relate process controls to initial and final pathogen and indicator densities).

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
  • Development of indicator pathogens for assessment of impact and attenuation in field situations.

REFERENCES

Alvarado, M.J., S.Armstrong, and E.Crouch. 2001. The AMSA 2000/2001 Survey of Dioxin-like Compounds in Biosolids: Statistical Analyses. Prepared by Cam bridge Environmental, Inc., Cambridge, MA, for the Association of Metropolitan Sewerage Agencies (AMSA). October 30, 2001. [Online]. Available: http://www.amsa-cleanwater.org/advocacy/dioxin/final_report.pdf [May 17, 2002].


Burnham, J.C., N.Hatfield, G.F.Bennett, and T.J.Logan. 1992. Use of kiln dust with quicklime for effective municipal sludge pasteurization and stabilization with the N-Viro soil process. Pp. 128–141 in Innovations and Uses for Lime, D.D.Walker Jr., T.B.Hardy, D.C.Hoffman, and D.D.Stanley, eds. ASTM STP 1135. Phildelphia, PA: American Society for Testing and Materials.

Burton, N.C., and D.Trout. 1999. NIOSH Health Hazard Evaluation Report: BioSolids Land Application Process, LeSourdsville, Ohio. HETA 98–0118–2748. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.


Cooperative State Research Service Technical Committee W-l70. 1989. Peer Review, Standards for the Disposal of Sewage Sludge, U.S. EPA Proposed Rule 40 CFR Parts-257 and 503 (February 6, 1989 Federal Register pp. 5746–5902). Submitted to William R.Diamond, Criteria and Standards Division, U.S. Environmental Protection Agency . Washington, DC: U.S. Dept. of Agriculture, Cooperative State Research Service.

Council of the European Communities. 1986. Council Directive 86/278/EEC of 12 June 1986 on the Protection of the Environment, and in Particular of the Soil, When Sewage Sludge is Used in Agriculture. Community Legislation in Force. Document 386L0278. [Online]. Available: http://europa.eu.int/eur-lex/en/lif/dat/1986/en_386L0278.html. [September 12, 2001].


EPA (U.S. Environmental Protection Agency). 1979. Criteria for classification of solid waste disposal facilities and practices. Fed. Regist. 44(179):53460–53464. (September 13, 1979).

EPA (U.S. Environmental Protection Agency). 1981. Land Application of Municipal Sewage Sludge for the Production of Fruits and Vegetables: A Statement of Federal Policy and Guidance. SW 905. U.S. U.S. Environmental Protection Agency, U.S. Food and Drug Administration, and U.S. Department of Agriculture, Washington, DC.

EPA (U.S. Environmental Protection Agency). 1984. Municipal sludge management policy; Notice. Fed. Regist. 49(114):24849–24850. (June 12, 1984).

EPA (U.S. Environmental Protection Agency). 1985. Pathogen Risk Assessment Feasibility Study. EPA 600/6–88/003. Office of Research and Development,

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, U.S. Environmental Protection Agency, Cincinnati, OH. November 1985.

EPA (U.S. Environmental Protection Agency). 1989. Environmental Regulation and Technology: Control of the Pathogens in Municipal Wastewater Sludge for Land Application Under CFR Part 257. Office of Technology Transfer and Regulatory Support, U.S. Environmental Protection Agency, Cincinnati, OH. September 1989.

EPA (U.S. Environmental Protection Agency). 1990. National sewage sludge survey: Availability of information and data, and anticipated impacts on proposed regulations. Fed. Regist. 55(218):47210–47283. (November 9, 1990).

EPA (U.S. Environmental Protection Agency). 1991. Interagency policy on beneficial use of municipal sewage sludge on federal land. Notice. Fed. Regist. 56(138):33186–33188. (July 18, 1991).

EPA (U.S. Environmental Protection Agency). 1992. Technical Support Document for Reduction of Pathogens and Vector Attraction in Sewage Sludge. EPA 822/R-93–004. Office of Water, U.S. Environmental Protection Agency. November 1992.

EPA (U.S. Environmental Protection Agency). 1993. Federal Register: February 19, 1993. 40 CFR Parts 257, 403, and 503. The Standards for the Use or Disposal of Sewage Sludge. Final Rules. EPA 822/Z-93/001. U.S. Environmental Protection Agency.

EPA (U.S. Environmental Protection Agency). 1994. Federal register amendment to 40 CFR503. Fed. Regist. 59(38):9095–9100. (February 25, 1994).

EPA (U.S. Environmental Protection Agency). 1995a. A Guide to the Biosolids Risk Assessments for the EPA Part 503 Rule. EPA 832-B-93–005.Office of Wastewater Management, U.S. Environmental Protection Agency, Washington, DC. September 1995. [Online]. Available: http://www.epa.gov/owm/bio/503rule/index.htm [December 20, 2001].

EPA (U.S. Environmental Protection Agency). 1995b. Sewage sludge: Use or disposal standards. Fed. Regist. 60(206):54771–54792. (October 25, 1995).

EPA (U.S. Environmental Protection Agency). 1998. Part IV 40 CFR Parts 750 and 761. Disposal of polychlorinated biphenyls (PCBs). Final Rule. Fed. Regist. 63(124):35383–35474. (June 29, 1998).

EPA (U.S. Environmental Protection Agency). 1999a. Introduction to the National Pretreatment Program. EPA-833-B-98–002. Office of Wastewater Management, U.S. Environmental Protection Agency. February 1999. [Online]. Available: www.epa.gov/npdes/pubs/final99.pdf [March 19, 2002].

EPA (U.S. Environmental Protection Agency). 1999b. Environmental Regulations and Technology: Control of Pathogens and Vector Attraction in Sewage Sludge. EPA/625/R-92/013. Office of Research and Development, U.S. Environmental Protection Agency, Washington DC. [Online]. Available: http://www.epa.gov/ttbnrmrl/625/R-92/013.htm [January 4, 2002].

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

EPA (U.S. Environmental Protection Agency). 1999c. Standards for the use or disposal of sewage sludge. Proposed rule. Fed. Regist. 64(246):72045–72062. (December 23, 1999).

EPA (U.S. Environmental Protection Agency). 2000a. Progress in Water Quality: An Evaluation of the National Investment in Municipal Wastewater Treatment. EPA-832-R-00–008. Office of Wastewater Management, Office of Water, U.S. Environmental Protection Agency. June 2000. [Online]. Available: http://www.epa.gov/OWOWM.html/wquality/benefits.htm [May 16, 2002].

EPA (U.S. Environmental Protection Agency). 2000b. Water. Biosolids Management and Enforcement. Audit Report No. 2000-P-10. Office of Inspector General. March 20, 2000. [Online]. Available: http://www.epa.gov/oigearth/audit/list300/00P0010.pdf [December 20, 2001].

EPA (U.S. Environmental Protection Agency). 2000c. OECA’s Response to IG Report on Biosolids (2000-P-10). Memorandum from Steven A.Herman, Assistant Administrator, Office of Enforcement and Compliance Assurance, to Jonathan C.Fox, Assistant Administrator, Office of Water, U.S. Environmental Protection Agency, Washington, DC. June 23, 2000.

EPA (U.S. Environmental Protection Agency). 2001a. Final Audit Report on Biosolids Management and Enforcement (No. 2000-P-10). Memorandum to Michael Simmons, Deputy Assistant Inspector General for Internal Audits, from Diane C.Regas, Acting Assistant Administrator, Office of Water, U.S. Environmental Protection Agency, Washington, DC. June 11, 2001.

EPA (U.S. Environmental Protection Agency). 2001b. Agency Response to Biosolids Management and Enforcement Audit Report No. 2000-P-10. Memorandum to G.Tracy Mehan, Assistant Administrator for Water, and Sylvia K.Lowrance, Acting Assistant Administrator for Enforcement and Compliance Assurance, from Judith J.Vanderhoef, Project Manager, Headquarters Audit Division. October 5, 2001.

EPA (U.S. Environmental Protection Agency). 2001c. Workshop on Emerging Infectious Disease Agents and Associated With Animal Manures, Biosolids and Other Similar By-Products, Cincinnati, OH, June 4–6, 2001. National Risk Management Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH.

EPA (U.S. Environmental Protection Agency). 2002a. Standards for the Use or Disposal of Sewage Sludge; Notice. Fed. Regist. 67(113):40554–40576. (June 12, 2002).

EPA (U.S. Environmental Protection Agency). 2002b. Biosolids Management and Enforcement OIG Audit Report No. 2000-P-10. Memorandum to Judith J. Vanderhoef, Project Manager, Headquarters Audit Division, and Michael Wall, Acting Divisional Inspector for Audit, Headquarters Audit Division, from G.Tracy Mehan, Assistant Administrator for Water, and Sylvia K.Lowrance, Acting Assistant Administrator for Enforcement and Compliance, Assurance , U.S. Environmental Protection Agency, Washington, DC. Jan. 30, 2002.

EPA (U.S. Environmental Protection Agency). 2002c. Land Application of Biosolids. Status Report. 2002-S-000004. Office of Inspector General, U.S. Environmental Agency. March 28, 2002.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

European Communities. 2001. Disposal and Recycle Routes for Sewage Sludge. Part 1. Sludge Use Acceptance. Part 2. Regulatory Report. European Communities, DG Environment. Luxembourg: Office for Official Publications of the European Communities. October 2001. [Online]. Available: http://europa.eu.int/comm/environment/sludge/sludge_disposal.htm [March 27, 2001].

European Union. 2000a. Waste management. Chapter 4 in Handbook for Implementation of EU Environmental Legislation. Enlargement and Co-Operation with European Third Countries. Europa. The European Union On-Line. [Online]. Available: http://europa.eu.int/comm/environment/enlarg/handbook/waste.pdf. [September 12, 2001].

European Union. 2000b. Working Document on Sludge, 3rd Draft. ENV.E.3/LM. European Union, Brussels. April 27, 2000. The European Union On-Line. Available: http://europa.eu.int/comm/environment/sludge/sludge_en.pdf [March 20, 2002].

Gendebien, A., C.Carlton-Smith, M.Izzo, and J.E.Hall. 1999. UK. Sewage Sludge Survey-National Presentation. R&D Technical Report P 165. Environmental Agency, Bristol, UK.

GLUMB (Great Lakes-Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers) . 1997. Recommended Standards for Wastewater Facilities. Albany, NY: Health Education Service.

Green, L.C., E.A.C.Crouch, S.R.Armstrong, T.L.Lash, and R.L.Lester. 1995. Comments on: Estimating Exposure to Dioxin-Like Compounds: Review Draft. Cambridge Environmental Inc., Cambridge, MA. January 12, 1995.


Haas, C.N. 2001. Assessment of the PEC Process. Report to U.S. EPA Pathogen Equivalency Committee (PEC), Philadelphia, PA. Drexel University, Philadelphia, PA. January 2, 2001.

Harrison, E.Z., and M.M.Eaton. 2001. The role of municipalities in regulating the land application of sewage sludges and spetage. Nat. Res. J. 41(1):77–123.


Keeney, D.R., K.W.Lee, and L.M.Walsh. 1975. Guidelines for the Application of Wastewater Sludge to Agricultural Land in Wisconsin. Technical Bulletin 88. Madison, WI: Department of Natural Resources.

Kelley, E.F. 2000. Vermont Biosolids Dioxin Sampling Project, Final Report. Vermont Department of Environmental Conservation. December 7, 2000.

Kester, G. 2000a. Letter to Chairman F.James Sensenbrenner, U.S. House of Representative, Committee on Science, Washington, DC, from G.Kester, State Residuals Coordinator, Bureau of Watershed Management, State of Wisconsin, Department of Natural Resources, Madison, WI. April 6, 2000.

Kester, G. 2000b. Letter to Michael Cook, Director, Office of Wastewater Management, U.S. Environmental Protection Agency, Washington, DC, from G.Kester, Wisconsin Residuals Coordinator, Bureau of Watershed Management, State of Wisconsin, Department of Natural Resources, Madison, WI. February 23, 2000.

Kester, G. 2000c. Letter to Mike Cook, Director, Office of Wastewater Management, U.S. Environmental Protection Agency, Washington, DC, from G. Kester, Wisconsin Residuals Coordinator, Bureau of Watershed Management, State of Wisconsin, Department of Natural Resources, Madison, WI. October 2, 2000.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

Kester, G. 2001a. Letter to Michael B.Cook, Director, Office of Wastewater Management; Elaine G.Stanley, Director, Office of Compliance; Brian J.Maas, Director, Water Enforcement Division; Eric V.Schaffer, Director, Office of Regulatory Enforcement; Elliott J.Gilberg, Director, Chemical, Commercial Services and Municipal Division; and Frederick F.Stiehl, Director, Environmental Planning, Targeting and Data Division, U.S. Environmental Protection Agency, Washington, DC, from G.Kester, State Residuals Coordinator, Bureau of Watershed Management, State of Wisconsin, Department of Natural Resources, Madison, WI. January 9, 2001.

Kester, G. 2001b. Letter to The Honorable Christine Todd Whitman, Administrator, U.S. Environmental Protection Agency, Washington, DC, from G.Kester, State Residuals Coordinator, Bureau of Watershed Management, State of Wisconsin, Department of Natural Resources, Madison, WI. September 10, 2001.

King County. 2000. Biosolids Quality Summary. Biosolids Management Program. King County Department of Natural Resources, Wastewater Treatment Division, Seattle, WA. July 2001.

Kowal, N.E. 1985. Health Effects of Land Application of Municipal Sludge. EPA/600/1–85/015. Health Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC. (cited in EPA 1992).

Lodor, M.L. 2001. NIOSH reports omits significant details in LeSourdsville case. Biosolids Technical Bulletin 7(4):11–13.


Matthews, P., ed. 1996. Global Atlas of Wastewater Sludge and Biosolids Use and Disposal. Scientific and Technical Report No. 4. London: International Association on Water Quality. 197 pp.

McGrath, S.P., A.C.Chang, A.L.Page, and E.Witter. 1994. Land application of sewage sludge: Scientific perspectives of heavy metal loading limits in Europe and the United States. Environ. Rev. 2:108–118.

Meyer, G.E. 1998. Letter to J.Charles Fox, Assistant Administrator, Office of Water, U.S. Environmental Protection Agency, Washington, DC, from G.E.Meyer, Secretary, State of Wisconsin, Department of Natural Resources, Madison, WI. November 13, 1998.

MMSD (Milwaukee Metropolitan Sewerage District). 2001. Pretreatment Program Effectiveness Analysis 2000. Milwaukee Metropolitan Sewerage District. May 2001.


NIOSH (National Institute for Occupational Safety and Health). 2000. Workers Exposed to Class B Biosolids During and After Field Application. NIOSH Hazard ID. HID 10. DHHS (NIOSH) 2000–158. National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services. August 2000.

NIOSH (National Institute for Occupational Safety and Health). 2002. Guidance for Controlling Potential Risks to Workers Exposed to Class B Biosolids. DHHS (NIOSH) 2002–149. National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services. Preprint, June 12, 2002.

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

NRC (National Research Council). 1996. Use of Reclaimed Water and Sludge in Food Crop Production. Washington, DC: National Academy Press.

O’Connor, G., R.B.Brobst, R.L.Chaney, R.L.Kincaid, L.R.McDowell, G.M. Pierzynski, A.Rubin, and G.G.Van Riper. 2001. A modified risk assessment to establish molybdenum standards for land application of biosolids. J. Environ. Qual. 30(5):1490–1507.


Pedersen, D. 1981. Density Levels of Pathogenic Organisms in Municipal Wastewater Sludge: A Literature Review. EPA-600/2–81–170. NTIS PB82–102286. Boston, MA: Camp Dresser & McKee, Inc.

Peavy, H.S., D.R.Rowe, and G.Tchobanoglous. 1985. P. 278 in Environmental Engineering. New York: McGraw-Hill.

Portland 2002. Biosolids Management Plan. Bureau of Environmental Services, City of Portland. February 2002.


Razvi, A. 2000. Audit Report of DNR Septage Management Program. College of Natural Resources, University of Wisconsin-Stevens Point. August 15, 2000.

Reimers, R.S., A.C.Anderson, A.A.Abdelhgani, M.C.Lockwood, and L.E.White. 1986a. The usage of non-ionizing irradiation processes in the disinfection of water and wastes. Pp. 272–299 in Applied Fields for Energy Conservation, Water Treatment, and Industrial Applications, Final Report, R.S.Reimers, S.F.Bock, and L.E.White, eds. DOE/CE/40568-T1 (DE86014306). Washington, DC: Technical Information Center, Office of Scientific and Technical Information, U.S. Department of Energy. June 1986.

Reimers, R.S., M.D.Little, A.J.Englande, D.B.McDonell, D.D.Bowman, and J.M. Hughes. 1986b. Investigation of Parasites in Sludges and Disinfection Tech niques. EPA 600/1–85/022. NTIS PB 86–135407. Prepared by the School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, for the Health Effects Research Laboratory, Research Triangle Park, NC.

Reimers, R.S., A.J.Englande, R.M.Bakeer, D.D.Bowman, T.A.Calamari, H.B.Brad ford, C.F.Dufrechou, and M.M.Atique. 1999. Update on Current and Future Aspects of Resource Management for Animal Wastes. WEFTEC ’99 Pre-Con ference Workshop “Beneficial Use of Animal Waste Residuals-A Mandatory Aim for the 21st Century.” Water Environment Federation, Alexandria, VA. October 1999.

Reimers, R.S., D.D.Bowman, P.L.Schafer, P.Tata, B.D.Leftwich, and M.M.Atique. 2001. Factors Affecting Lagoon Storage Disinfection of Biosolids. Proceedings of Joint WEF/AWWA/CWEA Specialty Conference “Biosolids 2001”, CD-ROM. Water Environmental Federation, Alexandria, VA. February 2001.


Stehouwer, R.C., A.M.Wolf, and W.T.Doty. 2000. Chemical monitoring of sewage sludge in Pennsylvania: Variability and application uncertainty. J. Environ. Qual. 29(5):1686–1695.


U.K. Department of the Environment. 1993. Sludge Use in Agriculture 1990/1991. Report to the EC Commission Under Directive 86/278/EEC. Department of the Environment. HMSO, London.


Wisconsin Administrative Code. 1996. Domestic Sewage Sludge Management. Chapter NR 204. Register 491:15–37. Department of Natural Resources, State

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×

of Wisconsin Department of Administration. [Online]. Available: http://www.doa.state.wi.us/dsas/docserv/docsales/wiscode.asp [March 27, 2002].

Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 31
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 32
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 33
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 34
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 35
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 36
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 37
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 38
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 39
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 40
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 41
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 42
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 43
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 44
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 45
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 46
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 47
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 48
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 49
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 50
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 51
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 52
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 53
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 54
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 55
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 56
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 57
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 58
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 59
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 60
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 61
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 62
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 63
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 64
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 65
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 66
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 67
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 68
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 69
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 70
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 71
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 72
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 73
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 74
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 75
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 76
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 77
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 78
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 79
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 80
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 81
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 82
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 83
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 84
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 85
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 86
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 87
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 88
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 89
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 90
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 91
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 92
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 93
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 94
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 95
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 96
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 97
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 98
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 99
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 100
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 101
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 102
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 103
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 104
Suggested Citation:"2 Biosolids Management." National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. Washington, DC: The National Academies Press. doi: 10.17226/10426.
×
Page 105
Next: 3 Epdiemiological Evidence of Health Effects Associated with Biosolids Production and Application »
Biosolids Applied to Land: Advancing Standards and Practices Get This Book
×
Buy Paperback | $60.00 Buy Ebook | $48.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

The 1993 regulation (Part 503 Rule) governing the land application of biosolids was established to protect public health and the environment from reasonably anticipated adverse effects. Included in the regulation are chemical pollutant limits, operational standards designed to reduce pathogens and the attraction of disease vectors, and management practices. This report from the Board on Environmental Studies and Toxicology evaluates the technical methods and approaches used by EPA to establish those standards and practices, focusing specifically on human health protection. The report examines improvements in risk-assessment practices and advances in the scientific database since promulgation of the regulation, and makes recommendations for addressing public health concerns, uncertainties, and data gaps about the technical basis of the biosolids standards.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!