Guidelines and Permitting for Livestock Anaerobic Digesters
Biogas recovery systems that use anaerobic digestion are sophisticated systems. To help you plan and optimize your anaerobic digester, AgSTAR provides the following information:
Anaerobic Digester Guidelines
These resources can help you evaluate anaerobic digester designs, build and implement an anaerobic digester, and operate and maintain the system:
- AgSTAR Handbook: A Manual For Developing Biogas Systems at Commercial Farms is a comprehensive manual that provides guidance on developing biogas recovery systems at commercial farms.
- Anaerobic Digester Conservation Practice Standard No. 366 (PDF) (8 pp, 144 K) provides technical guidelines for plug flow digesters, complete mix digesters, and covered lagoons (USDA Natural Resources Conservation Service, 2009).
- Common Safety Practices for On-Farm Anaerobic Digestion Systems identifies major hazards associated with anaerobic digesters and outlines practices to ensure a safe work environment for farms with these systems.
Codigestion Guidelines
Codigestion occurs when more than one type of organic waste is fed into an anaerobic digester. Codigestion can increase methane production from low-yielding or difficult to digest farm-based feedstocks.
- Increasing Anaerobic Digestion Performance with Codigestion fact sheet answers basic technical questions about codigestion
Codigestion Feedstocks
Codigestion feedstocks can be collected from other nearby sources including restaurant or cafeteria food wastes; food processing wastes or byproducts; fats, oil and grease from restaurant grease traps; energy crops; crop residues; and others. Codigestion feedstocks should be carefully selected to enhance—not inhibit—methane production.
Testing potential codigestion feedstocks helps owners understand the potential for biogas production, effects on methane production and other attributes. Methods for testing attributes of codigestion feedstocks include:
- Biochemical Methane Potentials (BMPs)
Biochemical Methane Potentials (BMPs) predict the amount of biogas and/or methane production from the codigestion substrate
- Evaluation of the "ultimate" anaerobic biodegradability of organic compounds in digested sludge, Method by measurement of the biogas production (ISO Standard 11734: 1995)
- Faivor, L., and D. Kirk. (2011). Statistical verification of a biochemical methane potential test. In Proceedings of American Society of Agricultural and Biological Engineers, Louisville, Kentucky
- Anaerobic Toxicity Assays (ATAs)
Anaerobic Toxicity Assays (ATAs) predict whether the codigestion substrate inhibits biogas and/or methane production
- General test to determine inhibition of gas production of anaerobic bacteria; can provide information that helps predict the likely effect of a test material on biogas production in anaerobic digesters (ISO Standard 13641-1:2003)
- Test for low biomass concentrations can help estimate the potential effects of chemicals and wastewater to anaerobic processes in habitats with relatively low anaerobic biomass (ISO Standard 13641-2:2003)
- Total Solids and Volatile Solids
Total solids and volatile solids
- Solids, Standard Methods 2450 (cost: $69) provides methods for estimating total solids, fixed and volatile solids, and settleable solids
- Solids Residue, EPA Method 160.4 for approximating the amount of organic matter in the solid fraction of sewage, activated sludge, industrial wastes or bottom sediments
- Alkalinity or pH
Alkalinity or pH levels should be as close to neutral as possible in the digester environment
- Alkalinity, Standards Methods 2320B (cost: $69) is a method for determining alkalinity in water
- Determination of pH, ISO 10523:2008 (cost: ~US$90) is a method for determining the pH value in liquid sludge
- Standard Test Methods for Acidity or Alkalinity of Water, ASTM D1067-11 (cost: $43) is a method to determine acidity or alkalinity of all types of water
- Chemical Oxygen Demand (COD)
Chemical Oxygen Demand (COD)
- Determination of COD, EPA’s Method 410 determines COD in ground and surface waters, domestic and industrial wastes
The composition of feedstocks in anaerobic digesters also has a significant influence on the biogas produced. This resource discusses energy from common codigestion feedstocks:
- Basics of Energy Production through Anaerobic Digestion of Livestock Manure (PDF) Department of Agricultural and Biological Engineering, Purdue University
Laboratories that Conduct Testing of Anaerobic Digester Feedstocks
To find a university or private laboratory that tests anaerobic digester feedstocks, contact your system designer for references or contact your state university’s agriculture department.
Interconnection Guidelines
Interconnection is the physical linking of a biogas recovery system to the electrical power grid. Biogas recovery systems connected to the electrical power grid generate renewable energy, which is distributed to energy consumers on the grid. The sale of electricity can generate revenue for biogas recovery system owners. Additionally, renewable energy certificates (RECs) and other environmental credits can be earned from producing and distributing the energy.
Interconnection Guidelines provide general guidance for connecting a biogas recovery system to the electrical power grid.
Permitting
Anaerobic digesters must meet local, state and federal regulatory and permitting requirements for air, solid waste and water. These requirements are in addition to permitting requirements for Concentrated Animal Feeding Operations (CAFOs). Anaerobic digester permit requirements vary by location and change frequently. Local, state and federal resources can help you navigate the permit process.
Local Permit Requirements
Anaerobic digesters may be subject to local government permit requirements for a range of municipal issues, such as construction, zoning and stormwater management. Contact your local government to determine current rules before constructing or operating anaerobic digesters.
State Permit Requirements
In addition to administering federal regulations, state agencies also administer their own state air, solid waste and water permit requirements.
Consolidated or General Permit Process
Some states provide the option of a consolidated permit process, which has several benefits:
- Allows permit applicants to have all of their state environmental permits coordinated by one agency;
- Makes the process easier by providing a single point of contact for multiple permits;
- Identifies needed permits earlier in the process; and
- Decreases duplicate information to various agencies.
Contact your state environmental agency to determine current rules before constructing or operating anaerobic digesters.
Air
- Combustion devices used for energy generation may require state air permits if the devices operate over federal thresholds.
- Some states have additional state-specific thresholds that require state air permits.
Solid Waste
- Waste processing facilities are required to meet Resource Conservation and Recovery Act (RCRA) Subtitle D requirements (which cover non-hazardous solid wastes) and 40 CFR Part 258 (which covers landfills).
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Many states exempt manure-only anaerobic digesters from solid waste permit requirements.
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Some states may exempt all farm digester systems or only some systems based on the type and volume of feedstocks processed. For example, farms may require permits if they rely on codigestion, accept any offsite waste or accept offsite waste above a threshold amount.
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Water
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The presence of an anaerobic digester on a CAFO does not change the federal CAFO requirements, which some states administer.
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EPA considers large CAFOs as point sources of water pollution. Therefore, CAFOs require National Pollutant Discharge Elimination System (NPDES) permits. CAFOs also must develop and maintain Nutrient Management Plans to ensure appropriate land application of manure. Anaerobic digesters with solids separation may give farms more control over how they apply nutrients.
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Medium CAFOs may face similar requirements as large CAFOs. Some states include smaller farms in their animal feeding operations programs depending on past performance or other site conditions.
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Smaller farms must comply with the NPDES requirements if they discharge to waters of the U.S. through a manmade device or through direct contact of the animals with waters of the U.S.
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Some states have additional water permit requirements for farm-based anaerobic digester operations that codigest other feedstocks with manure.
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State-Specific Requirements
- California
Consolidated or General Permit Process
- The California Environmental Protection Agency (Cal/EPA) offers a consolidated permit process (PDF) (2 pp, 437K) for dairy digester projects. If requested, Cal/EPA will have one state agency coordinate environmental permits for a facility, which can make the process easier.
- Cal/EPA’s Dairy Digesters website provides permit resources for dairy digesters, such as flow charts for permit processes.
Air
- State-specific Thresholds: The California Air Resources Board (CARB) oversees 35 districts. Each district has different requirements depending on whether or not the district meets the National Ambient Air Quality Standards (NAAQS) for criteria pollutants. For example, the San Joaquin Valley Air Pollution Control District is an ozone non-attainment area, which means anaerobic digesters must meet additional requirements under the district’s permit process (PDF) (1 p, 47K).
- Combustion devices may require permits depending on the requirements of the specific air district. If organic feedstocks are added, the type of organic feedstocks may cause additional permit requirements.
Solid Waste
- CalRecycle permits facilities handling solid waste and certifies Local Enforcement Agencies (LEAs) as the primary contact overseeing solid waste activities within their jurisdictions. Search the LEA directory for contact information.
- Manure-only Exemption: Some agricultural facilities that digest their own "agricultural material" and do not sell or give away more than 1,000 cubic yards of compost annually are excluded from regulation.
- Codigestion: Facilities that codigest manure with offsite feedstocks require permits under either the Transfer/Processing Operations and Facilities Regulatory Requirements (Title 14, CCR 17400) or the Compostable Materials Handling Operations and Facilities Regulatory Requirements (Title 14, CCR 17850). Exclusions are available for small-scale and research activities.
Water
- The California State and Regional Water Boards manage and regulate water resource quality and waste discharges, including digester discharges. The State Water Resources Control Board map provides a list of the nine Regional Water Quality Control Boards.
- The Central Valley Region has the majority of the state’s dairy farms. This region developed general permits for dairy manure anaerobic digesters and codigestion facilities, either at a single site or in a centralized location.
- Idaho
Air
- The Idaho Department of Environmental Quality (IDEQ) administers air permits.
Solid Waste
- Manure-only: The Idaho State Department of Agriculture (ISDA) regulates manure-only anaerobic digesters under a facility’s nutrient management plan.
- Codigestion: IDEQ permits facilities under the state’s Solid Waste Management Rules if facilities have anaerobic digesters that codigest other feedstocks with manure.
Water
- The Idaho Department of Water Resources administers water permits.
- Illinois
- The Illinois Environmental Protection Agency (EPA) administers all permits.
Solid Waste
- Manure-only Exemption: Anaerobic digesters processing only manure do not require solid waste permits.
- Codigestion, Offsite Waste Acceptance: Illinois EPA considers anaerobic digesters as waste processing facilities if they process offsite feedstocks and requires permits unless they meet certain exemptions. Illinois State code 415 ILCS 5, Section 3.330(a)(19) lists these exemptions
- Indiana
- The Indiana Department of Environmental Management (IDEM) administers all permits.
Air
- IDEM’s Air Quality Permit Guide website contains information on air permits and application forms.
- State-specific Thresholds: New emission sources with combustion devices require air permits prior to construction and operation.
- Indiana has a combined construction and operation permit program.
- Indiana Administrative Code 326 IAC 2-1.1-3 includes some air permit exemptions that might apply to anaerobic digester operations.
Solid Waste
- IDEM’s Office of Land Quality requires facilities with anaerobic digesters to have one of the following: 1) solid waste processing facility permit, 2) CFO/CAFO approval or 3) biomass registration.
Water
- Codigestion: Anaerobic digesters processing organic feedstocks in addition to manure may be required to perform additional screening of either the anaerobic digester influent or effluent.
- Iowa
- The Iowa Department of Natural Resources (DNR) administers all permits.
- The Iowa Digester Experience (PDF) (22 pp, 1.5 MB), a 2009 presentation, provides general information on anaerobic digestion permit requirements.
- The Iowa DNR Animal Feeding Operations webpage provides resources for AFOs (not specific to anaerobic digesters) and regulations that affect them.
Solid Waste
- Manure-only Exemption: Anaerobic digesters processing only manure do not require solid waste permits.
- Codigestion: Anaerobic digesters processing non-manure organic feedstocks may require solid waste permits. Iowa evaluates facilities on a case-by-case basis.
Water
- Codigestion: Codigestion of offsite organic feedstocks may trigger additional requirements in the AFO’s discharge permit and adjustments to the nutrient management plan. This does not apply to manure-only digesters.
- Maine
- The Maine Department of Environmental Protection (DEP) administers all permits.
Solid Waste
- Manure-only Exemption: Anaerobic digesters processing only manure and agricultural feedstocks do not require a DEP license.
- Offsite Waste Acceptance: Anaerobic digesters processing offsite feedstocks, including only manure, require a DEP license.
- Chapter 419 of Maine’s Waste Management Rules provides detailed rules on farm use of offsite feedstocks.
- Massachusetts
- The Executive Office of Energy and Environmental Affairs, Department of Environmental Protection (DEP) administers all permits.
- The Executive Office of Energy and Environmental Affairs, Clean Energy Results Program provides general and permitting information on anaerobic digestion.
Consolidated or General Permit Process
- Massachusetts DEP has a general permit process (PDF) for anaerobic digesters that process manure below a certain daily volume.
Solid Waste
- Anaerobic digesters receiving more than 100 tons per day of organic feedstocks from on or offsite 1) require site assessments and 2) are not eligible for general permits.
- For additional information, see Massachusetts’ Site Assignment Regulations for Solid Waste Facilities (PDF) (310 CMR 16.04) (57 pp, 381K).
- Michigan
- The Michigan Department of Environmental Quality (MDEQ) administers all permits.
- The Environmental Regulations Affecting Anaerobic Digesters (PDF) (6 pp, 352K) fact sheet identifies regulations that may apply to anaerobic digesters at farms or food processing facilities.
Air
- State-specific Thresholds: Michigan DEQ generally exempts manure-based anaerobic digesters from air permitting requirements. Anaerobic digesters may not be exempt if the onsite combustion device 1) produces more than one pound of sulfur dioxide an hour, or 2) has a heat input capacity of greater than 10 million Btu per hour.
Solid Waste
- Manure-only Exemption: Anaerobic digesters processing only manure do not require solid waste permits.
- Codigestion: Michigan encourages facilities to work with the Michigan DEQ to determine what permits might be required.
- Farms adding non-manure feedstock to anaerobic digesters may need authorization before composting solids or applying to the land.
- MDEQ exempts several materials from permitting (PDF) (4 pp, 465K), including food processing residuals, syrup from ethanol production, grease trap wastes that do not contain septic tank sludge, and fish wastes. However, to be exempt, the anaerobic digester must not accept more than 20 percent of these other organics.
Water
- In general, anaerobic digesters accepting only manure are not required to obtain additional water discharge permits.
- Codigestion: Anaerobic digesters including non-manure organic feedstocks may require permits or land application authorization. Michigan DEQ encourages each facility to contact the Water Resources Division to discuss requirements.
- CAFO: Permitted CAFOs must include the anaerobic digester in their Nutrient Management Plan.
- Minnesota
- The Minnesota Pollution Control Agency (MPCA) administers all permits.
- Energy from Waste (Minnesota Department of Agriculture) provides basic information and resources about agricultural anaerobic digestion.
Solid Waste
- Manure-only Exemption: Anaerobic digesters processing only manure do not require solid waste permits.
- Codigestion: MPCA determines the need for a solid waste permit on a case-by-case basis for anaerobic digesters that process manure and other organic feedstocks. Project developers should contact MPCA solid waste staff to determine the need for an individual permit.
Water
- Codigestion: Anaerobic digesters processing non-manure organic feedstocks require individual permits.
- Nebraska
- The Nebraska Department of Environmental Quality administers all permits.
- The One Stop Permit Assistance Program guides businesses and industry through the permit process.
- New York
- The New York State Department of Environmental Conservation administers all permits.
Solid Waste
- Solid Waste and Water Regulatory Requirements for Wastes Managed on a Farm (PDF) (10 pp, 118K) provides guidance on regulations that apply specifically to farm waste.
- New York regulations for Quality Services, Part 360-5 applies to composting facilities. Subpart 360-5.3 lists exemptions, including exemptions for anaerobic digester facilities.
- Manure-only exemption: Anaerobic digesters that accept manure, bedding, crop residues and farm waste do not need Part 360 permits.
- Codigestion:
- Anaerobic digesters located on CAFOs having a Comprehensive Nutrient Management Plan may accept up to 50 percent non-manure feedstocks (by volume of their annual feedstock received) to qualify for an exemption from permit requirements.
- Anaerobic digesters processing more than 50 percent non-manure feedstocks require permits.
Water
- Solid Waste and Water Regulatory Requirements for Wastes Managed on a Farm (PDF) (10 pp, 118K) provides guidance on regulations that apply specifically to farm wastes. See solid waste for exemptions.
- Ohio
The Ohio Environmental Protection Agency (Ohio EPA) oversees compliance with environmental laws. Use the Ohio EPA Permit Wizard to identify the permits, licenses and other requirements needed for anaerobic digesters.
Air
- The Ohio EPA issues air permits and provides general permits for anaerobic digestion systems. The Ohio EPA provides model general permits for the following:
- Biomass digesters using a flare
- Digesters with a gas-fired boiler
- Digesters with a gas-fired, spark ignition internal combustion engine.
Solid Waste
- Codigestion:
- The Ohio Department of Agriculture issues permits for, and oversees, anaerobic digesters that accept
- Only manure, and
- Non-manure organic feedstocks less than 25 percent by volume.
- The Ohio EPA permits facilities that accept more than 25 percent (by volume) non-manure feedstocks.
- Facilities with anaerobic digesters must comply with their Nutrient Management Plan.
- The Ohio Department of Agriculture issues permits for, and oversees, anaerobic digesters that accept
Water
- The Ohio EPA and the Ohio Department of Agriculture manage water permits.
- Ohio Revised Code (ORC), Chapter 6111 does not require additional water permits for anaerobic digesters 1) located on permitted CAFOs and 2) processing less than 25 percent non-manure feedstocks.
- Codigestion: Use the Ohio EPA Permit Wizard to determine the permit required when adding feedstocks other than those generated on farms to the anaerobic digesters.
- The Ohio EPA issues air permits and provides general permits for anaerobic digestion systems. The Ohio EPA provides model general permits for the following:
- Oregon
- The Oregon Department of Environmental Quality (DEQ) administers all permits.
Air
- The Oregon DEQ Air Contaminant Discharge Permits website provides permit information and forms.
- Facilities producing a total of no more than 25 megawatts of electrical power require a general air contaminant discharge permit (PDF) (17pp, 260K).
- In 2015, Oregon DEQ published a new category of sources (Category 87) for stationary internal combustion engines that applies to anaerobic digesters.
Solid Waste
- Oregon DEQ regulates anaerobic digesters under composting (Oregon Administrative Rule (OAR) 340, Division 93). Oregon’s Special Rules for Selected Solid Waste Disposal Sites (OAR 340, Division 96) describes conditions and permit requirements. “Composting” facilities must comply with OAR 340-096-0060 through 340-096-0150: "Special Rules Pertaining to Composting."
Water
- Anaerobic digesters processing only manure at permitted CAFO facilities do not require additional permits. Digesters need to be incorporated into existing permits and Nutrient Management Plans.
- Anaerobic digesters operating at unpermitted CAFO facilities may require water permits, depending on the facility.
- Codigestion: Oregon DEQ reviews anaerobic digesters processing non-manure organic feedstocks. To date, Oregon DEQ has not required additional permits for anaerobic digesters at permitted CAFOs that accept non-manure organic feedstocks.
- Pennsylvania
- The Pennsylvania Department of Environmental Protection (PA DEP) administers all permits.
Consolidated or General Permit Process
- A General Permit (WMGM042) (PDF) (8 pp, 51K) authorizes anaerobic digestion of waste mixtures that include animal manure, grease trap waste, pre-consumer food, and wastewater from dairy farms. To obtain approval to operate under the general permit, facilities must obtain a “Determination of Applicability” from the appropriate regional office (see permit standard conditions for details).
Solid Waste
- Anaerobic digesters, including those that digest food processing feedstocks, do not require solid waste permits for land application.
Water
- Although not specific to farms with anaerobic digesters, farms producing or using manure require a Nutrient Management Plan. PA DEP does not require additional permits.
- Texas
- The Texas Commission on Environmental Quality (CEQ) administers all permits.
Air
- State-specific Thresholds: The Texas CEQ requires Permits by Rule (PBR) for facilities that produce some emissions but not enough to trigger federal permit requirements.
Solid Waste
- Texas CEQ determines permit requirements for anaerobic digesters on a case-by-case basis.
Water
- Texas CEQ determines permit requirements on a case-by-case basis depending on the location, how the anaerobic digester fits within the permitted activity at that location, and the type of materials digested.
- Vermont
Air
- The Vermont Department of Environmental Conservation (DEC) administers air permits.
- Vermont DEC generally does not require permits for anaerobic digesters as long as they meet the following requirements:
- combustion device meets federal thresholds;
- engine exhaust stack vents at a minimum of 4 feet above the nearest roof;
- backup combustion device meets the requirements of federal requirements listed in 40 CFR Part 60, Subpart A 60.18; and
- emission source registered with the agency in accordance with Vermont Air Pollution Control Regulations, Subchapter VIII.
- Vermont DEC typically does not require additional permits for anaerobic digesters using non-manure feedstocks but reviews additional feedstocks on a case-by-case basis.
Solid Waste
- The Vermont DEC administers solid waste permits.
- Manure-only exemption: Anaerobic digesters processing only manure do not require permits.
- Codigestion: Anaerobic digesters require permits if adding offsite food wastes that are more than one percent of the digester design capacity.
Wastewater
- The Vermont Agency of Agriculture administers permits for anaerobic digesters used for manure management.
- Anaerobic digesters processing only manure do not require additional permits.
- Codigestion: Anaerobic digesters that include food-processing residuals may require indirect discharge permits. The VT DEC Drinking Water and Groundwater Protection Division coordinates with the Agency of Agriculture for projects with land application on farms to determine: 1) additional storage needs for the non-manure feedstocks and 2) amount of nutrients allowed in the wastewater released by the farms. Indirect discharge permits (per 10 V.S.A. §1263), which are issued to those producing the food-processing residuals, include the name of the farms receiving the food-processing residuals.
- Washington
- The Governor’s Office for Regulatory Innovation and Assistance helps people navigate Washington’s regulations and provides information and resources on environmental permits. Some of the resources include:
- Regulatory Handbook that provides in-depth information regarding regulatory permits, approvals and licenses’ and
- Project Questionnaire that helps people determine if their project requires permits.
Air
- Washington’s Department of Ecology (Ecology) regulates counties without an air pollution control agency. The Regulatory Handbook provides information for those counties that Ecology regulates, which includes Adams, Asotin, Chelan, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Kittitas, Klickitat, Lincoln, Okanogan, Pend Oreille, San Juan, Stevens, Walla Walla, and Whitman counties. Other counties have local clean air agencies that may have stricter requirements.
- State-specific Thresholds: Ecology requires a Notice of Construction air quality permit for new or modified sources that produce over a certain amount of air pollution. See Table 110(5) in the New source review (NSR) for sources and portable sources (Washington Administrative Code (WAC) 173-400-110(5)) for the levels of various pollutants that trigger permits.
- General Order Permits apply to new or modified dairy manure anaerobic digesters that meet certain conditions and operate in a county that Ecology regulates.
Solid Waste
- Washington’s Department of Ecology (DEQ) issues solid waste handling permits for anaerobic digesters (WAC 173-350).
- Exemption for manure-based systems:
- Anaerobic digesters may be exempt from solid waste handling permits if all of the following apply to the feedstock:
- Contains at least 50 percent manure;
- Has no more than 30 percent other offsite, non-manure organic feedstocks; and
- All offsite organic feedstocks are pre-consumer.
- Table 250-A of WAC 173-350-250 lists terms and conditions of exemptions. The Washington’s DEQ must approve feedstocks not listed in Table 250-A.
- See RCW 70.95.330 for additional information on exemptions.
- Anaerobic digesters may be exempt from solid waste handling permits if all of the following apply to the feedstock:
Water (CAFO General Permit information)
- Codigestion: CAFOs with anaerobic digesters do not require additional water quality permits. If the system digests non-manure organic feedstocks, the Nutrient Management Plan must reflect these wastes.
- The Governor’s Office for Regulatory Innovation and Assistance helps people navigate Washington’s regulations and provides information and resources on environmental permits. Some of the resources include:
- Wisconsin
- The Wisconsin Department of Natural Resources (DNR) administers all permits. Wisconsin DNR produced an interactive “Permit Primer” to help businesses determine which permits they need.
Solid Waste
- Codigestion: CAFOs must get approval before adding non-manure feedstocks to anaerobic digesters. There may be additional permit requirements if the anaerobic digesters contain less than 90% manure. The state may also require permits depending on what is added, even if less than 10%.
Federal Regulatory Requirements
The federal government issues regulations. These regulations establish the minimum guidelines a state can use for permitting. More restrictive state regulations replace federal regulations.
Air
Onsite combustion devices used for energy generation may require federal permits if the devices trigger federal emissions thresholds and other federal regulatory permit requirements. Conversely, if air emissions from these devices are below federal thresholds they may be exempt from permit requirements. The following regulations establish the federal thresholds:
- Standards of Performance for New Stationary Sources (40 CFR Part 60)
- Standards of Performance for Stationary Spark Ignition Internal Combustion Engines (40 CFR Part 60, Subpart JJJJ)
- Standards of Performance for Stationary Compression Ignition Internal Combustion Engines (40 CFR Part 60, Subpart IIII)
- Standards of Performance for Industrial-Commercial-Institutional Steam Generating Units (40 CFR Part 60, Subpart Db)
- Standards of Performance for Small Industrial-Commercial-Institutional Steam Generating Units (40 CFR Part 60, Subpart Dc)
- Stationary Internal Combustion Engines (40 CFR Part 63, Subpart ZZZZ)
- EPA's National Ambient Air Quality Standards (40 CFR part 50) identifies emissions standards for criteria air pollutants (ozone, PM, CO, NOx, sulfur dioxide, and lead)
- Controlling Air Pollution from Boilers and Process Heaters
Solid Waste
- Waste processing facilities must meet Resource Conservation and Recovery Act (RCRA) Subtitle D requirements (which cover non-hazardous solid wastes) and 40 CFR Part 258 (which covers landfills). See Managing Non-Hazardous Municipal and Solid Waste.
- Federal laws do not require solid waste permits for the anaerobic digestion of manure at farms. However, the acceptance of other organics may designate farms with anaerobic digesters as waste processing facilities in some states.
Water
There are no national water-related permit requirements specifically triggered by use of anaerobic digesters.