EPA 430-B-20-003 Anaerobic Digester/Biogas System Operator Guidebook
EPA 430-B-20-003Anaerobic Digester/Biogas SystemOperator GuidebookA Guidebook for Operating Anaerobic Digestion/BiogasSystems on Farms in the United StatesNovember 2020
AgSTAR Operator GuidebookPREFACEU.S. EPA AgSTAR ProgramAgSTAR is a voluntary outreach program that encourages the implementation of anaerobicdigestion (AD) projects in the agricultural and livestock sector to reduce methane (CH4)emissions from agricultural residuals including livestock waste. AD projects can be cost-effectivemitigation techniques and provide numerous co-benefits to the local communities where theyare installed, including environmental, energy, financial, and social sector benefits.AgSTAR is a collaborative program sponsored by the U.S. Environmental Protection Agency(EPA) and the U.S. Department of Agriculture (USDA) that promotes the use of biogas recoverysystems to reduce CH4 emissions from livestock waste. As an education and outreach program,AgSTAR disseminates information relevant to livestock AD projects and synthesizes it forstakeholders who implement, enable, or purchase AD projects. The program’s goals are toprovide information that helps stakeholders evaluate the appropriateness of an AD project in aspecific location, to provide objective information on the benefits and risks of AD projects, andto communicate the status of AD projects in the livestock sector. Through the AgSTAR website(www.epa.gov/agstar) and at public events and other forums, AgSTAR communicates unbiasedtechnical information and helps create a supportive environment for the implementation oflivestock AD projects.AgSTAR provides technical input to the USDA Rural Energy for America Program, which providesgrant funding for AD systems at farms.AgSTAR works collaboratively with livestock producers, the digester and biogas industry,policymakers, universities, and others to provide unbiased information to assess the use ofanaerobic digesters. By identifying project benefits, risks, and options, AgSTAR provides criticalinformation to determine whether an AD system is the right choice for an operation.PREFACEi
AgSTAR Operator GuidebookAnaerobic Digester Operator Guidebook PurposeThe purpose of this Anaerobic Digester/Biogas System Operator Guidebook is to help on-farmAD and biogas (AD/biogas) system operators improve performance and efficiency. It is alsointended to assist in the prevention of common difficulties and challenges that can lead tocommunity opposition and system shutdown. This Operator Guidebook covers technical topicsfor a wide range of stakeholders. It is intended to be a resource that helps operators maximizeprofitability by optimizing biogas yield, improving biogas quality, and improving operatinguptime, while minimizing operations and maintenance (O&M) expenses. The OperatorGuidebook spans all aspects of on-farm AD/biogas production as well as certain utilizationprocesses, providing industry expert experience and suggestions for dealing with performance,safety, and other issues commonly encountered with AD/biogas systems.DisclaimerThis Operator Guidebook complements other AgSTAR resources for developing biogas projectson U.S. farms. It is designed to be used in combination with the third edition of the AgSTARProject Development Handbook. The Project Development Handbook and the OperatorGuidebook were collectively prepared to improve the successful development, implementation,and operation of on-farm AD/biogas systems.While this Operator Guidebook addresses numerous aspects of AD/biogas systems, it is notpossible to cover every component, as there are many different types of systems, and eachAD/biogas project is unique. Therefore, this document should not be considered fullycomprehensive, nor should it be used in place of a site-specific O&M manual. Rather, it shouldbe considered a supplement to the operations manual provided by the project developer or theengineering firm that prepared the project design and supervised the construction and start-upof an AD/biogas system. Project stakeholders may utilize this document to ensure thatdeveloping or existing site-specific O&M plans cover a baseline of topics needed for successfulproject operation. The Operator Guidebook will be updated as AD/biogas systems evolve.Pursuant to 5 CFR § 2635.702(c)(2), names are displayed here as the result of recognition forachievement given under an agency program of recognition for accomplishment in support ofthe agency’s mission. Any reference to a specific company or commercial product or service bytrade name, trademark, manufacturer, company, or otherwise does not constitute or imply theendorsement or recommendation of EPA.AcknowledgmentsThe EPA’s AgSTAR Program would like to acknowledge the many individuals and organizationalcontributors who supported the update and enhancement of this 3rd version of the ProjectDevelopment Handbook.Within EPA, work was led and directed by Nick Elger, AgSTAR & Global Methane Initiative;Program Manager and Vanessa McKinney, AgSTAR Program Manager.PREFACEii
AgSTAR Operator GuidebookEPA also wishes to acknowledge and thank the following individuals who conducted a technicaland independent review of the document: Craig Frear, Regenis; Brian Langolf, University ofWisconsin – Oshkosh; Bernie Sheff, Montrose Environmental Group, Inc. and Mark Stoermann,Newtrient These industry experts also serve on the American Biogas Council’s OperationsCommittee, in order to offer AD/Biogas system Operators a Best Practices Guide, on-sitetraining, online training, and operators certification.This document was prepared by Eastern Research Group, Inc. through a technical supportcontract with EPA in support of AgSTAR. EPA wishes to especially acknowledge the efforts ofstaff including Cortney Itle and Amber Allen. EPA would also like to acknowledge the valuableinput from Dr. John Martin from Hall Associates.EPA also wishes to acknowledge and thank the following Tetra Tech staff who providedsignificant technical and operational expertise in the development of the Operator Guidebook:primary authors David Palmer and Phil Lusk. Supporting authors Chris Noah, Keith Henn, JeffGeer, and Jennifer Guo. Project management Cathy McGirl and Steve Michener.PREFACEiii
AgSTAR Operator GuidebookTable of ContentsAcronyms . iixIntroduction . 1-1Digester Basics . 2-12.1What Does an Anaerobic Digester Do? . 2-12.3Types of Anaerobic Digesters . 2-32.22.42.5How Does an Anaerobic Digester Work? . 2-1Key Factors for AD Efficiency and Performance . 2-5AD/Biogas System Components . 2-52.6Fundamentals of Biogas Safety . 2-6Operational Fundamentals . 3-13.1Retention Time. 3-13.43.5Degradable Organic Material Conversion and Limitations . 3-2Biomethane Potential . 3-34.1Consistent Loading. 4-13.23.3Organic Loading Rate (OLR) . 3-1Operating Temperature . 3-23.6Anaerobic Toxicity Assays (ATAs) . 3-4Process Control. 4-14.24.34.4Performance Monitoring . 4-2Biogas Monitoring . 4-2Digester Monitoring . 4-2Effluent Monitoring . 4-3Co-Digestion Recordkeeping . 4-3Critical Issues Analysis and AD Performance. 4-3Digester Loading Risks . 4-3Foaming . 4-44.5Critical Issues Response. 4-45.15.2What Tests Should You Do? . 5-1Where Samples Should Be Taken and Proper Sampling Procedures . 5-2Laboratory Testing and Data Recording . 5-15.35.4Frequency of Testing . 5-3Data Evaluation . 5-46.1Pumps. 6-1Pump Types . 6-1Fundamentals of Digester Mechanical Systems. 6-1Redundancy . 6-2Table of Contentsiv
AgSTAR Operator Guidebook6.26.3Piping Systems . 6-3Mixing. 6-3Why Mix? . 6-3Mix Where? . 6-3What Are the Mixer Types? . 6-36.4What Are Mixer Maintenance Concerns?. 6-4Influent and Effluent Management . 6-4Pretreatment . 6-5Flow Equalization. 6-5Digestate Processing/Storage . 6-5Biogas Handling and Conveyance . 7-17.1Biogas Handling and Conveyance . 7-17.27.3Leak Testing . 7-1Pressure Regulation . 7-27.6Valves. 7-47.47.57.77.87.9Condensate Removal and Freeze Protection . 7-3Piping. 7-4Blowers and Compressors . 7-6Biogas Use . 7-6Combined Heat and Power (CHP). 7-6Boilers and Furnaces . 7-7RNG . 7-7Biogas Processing . 7-7Processing for Onsite Combustion . 7-7Upgrading to RNG . 7-9System Inspection and Maintenance . 8-18.1General Maintenance Requirements . 8-1Routine Versus Major Maintenance . 8-1Impact of Process Conditions on Frequency . 8-1Monitoring Changes in Process Conditions . 8-1Insulation and Freeze Protection. 8-2Housekeeping. 8-2Buildings/Heating, Ventilation, and Air Conditioning (HVAC) . 8-2Site safety . 8-2Third-Party Expertise . 8-2Warranty . 8-3Digester Tanks and Vessels . 8-3PRVs. 8-3Table of Contentsv
AgSTAR Operator GuidebookDrains and Vents . 8-3Leaks. 8-38.2Corrosion Monitoring . 8-3Fresh/Waste Oil Storage Tanks . 8-4AD Mechanical System Maintenance . 8-4Pumps . 8-4Mixers . 8-58.3Heat Exchangers . 8-5Biogas System Maintenance . 8-6Blowers and Compressors. 8-6Heat Exchangers . 8-7Particulate Filters . 8-78.4Coalescing Filter/Separator . 8-7Power and Heat Generation O&M . 8-7IC Engine. 8-7Routine . 8-8Oil Changes . 8-8Monitoring . 8-8Overhauls. 8-8Heat Exchangers and Pumps . 8-8Boilers . 8-98.5Chillers . 8-9Biogas Upgrading System Maintenance . 8-10H2S Removal . 8-10Bulk Moisture Removal . 8-10CO2 Removal . 8-11Dehydration . 8-11Compression . 8-11Activated Carbon and Other Media . 8-128.6Flare Maintenance . 8-12Odors and Odor Control . 9-19.19.2What Are Odors?. 9-1How Can Odors Impact the Viability of an AD Operation?. 9-1Potential Odor Sources . 9-1What Do Unusual Odors Mean? . 9-1Odor Control . 9-2Building Control . 9-2Source Control. 9-3Table of Contentsvi
AgSTAR Operator GuidebookOdor Treatment . 9-3Biofiltration . 9-3Chemical Scrubbing . 9-3Adsorption . 9-3Odor Masking . 9-4Minimizing Odors During Operation . 9-4Safety .10-110.1Biogas Safety Considerations . 10-1Flammability and Explosion. 10-2Explosive Gas Hazard Zones . 10-3Toxic Gases . 10-4Personal Detection Device . 10-510.2Permanent Gas Detection . 10-5Toxicity Hazard Zones . 10-5General Safety Considerations . 10-5Material Handling. 10-5Confined Space . 10-6Ventilation . 10-7Slips, Trips, and Falls. 10-7Electric Shock . 10-7Electrical Fire . 10-8Entanglement. 10-8High Pressure . 10-8Extreme Temperature . 10-8Noise . 10-8Drowning . 10-910.3Pests . 10-9Safety Conclusions. 10-10Table of Contentsvii
AgSTAR Operator GuidebookList of TablesTable 4-1. Digester failure relationships.4-5Table 5-1. Recommended sampling for operating parameters. .5-1List of FiguresFigure 2-1. The four steps of anaerobic biodegradation. .2-2Figure 2-2. Photograph of an anaerobic digester facility (a patented sequential-batchsystem). .2-4Figure 3-1. Methods of biomethane potential determination.3-3Figure 4-1. Biogas fluctuation with feedstock variability. .4-1Figure 2-1. Pump type examples.6-2Figure 6-2. Illustration of a submersible mechanical mixer. .6-4Figure 7-1. Gas analyzer and flow diagram of sequence and gas analyzer. .7-2Figure 7-2. Examples of PRVs. .7-3Figure 7-3. Photograph and schematic of an isolation valve. .7-5Figure 7-4. Cross-section of a packed tower scrubber for an H2S removal system.7-8Figure 7-5. Cross-section of a typical adsorber bed. . 7-10Figure 7-6. Schematic diagram of a membrane permeation. . 7-11Figure 7-7. Water scrubbing unit flow schematic. . 7-11Figure 10-1. Safety signage on AD feed system. . 10-2Figure 10-2. Explosion potential sign. . 10-4List of Tables and Figuresviii
AgSTAR Operator GuidebookAcronymsADanaerobic digestionBMPbiochemical methane potentialATABODCH4anaerobic toxicity assaysbiochemical oxygen demandmethaneCHPcombined heat and powerCODchemical oxygen demandCO2EPAcarbon dioxideU.S. Environmental Protection AgencyH2Shydrogen sulfideHVACheating, ventilation, and air conditioningHRTICIDLHkgLlbhydraulic retention timeinternal combustionImmediately Dangerous to Life and HealthkilogramliterpoundLELlower explosive limitNH3ammoniaO&Moperations and maintenanceOSHAOccupational Safety and Health AdministrationPRVpressure relief valveRNGrenewable natural gasmgO2OLRppmPSASRTmilligramatmospheric oxygenorganic loading rateparts per millionpressure swing adsorptionsolids retention timeTKNtotal Kjeldahl nitrogenUELupper explosive limitTSVFAVSAcronymstotal solidsvolatile fatty acidvolatile solidsix
AgSTAR Operator GuidebookIntroductionAnaerobic digestion (AD) and biogas systems are designed to convert biodegradable organicmaterials into recoverable methane (CH4)-rich gas and a stabilized digestate using a welldocumented, complex biological process.A successful AD/biogas system operator has one primary objective: provide the microorganismsin the digester with a favorable environment to maintain a stable population. If this stability isachieved, the microorganisms will efficiently convert readily biodegradable organic materialsinto biogas and other products, which can then be captured and utilized, prohibiting theirrelease into the environment. Achieving this primary objective is challenging because AD/biogassystems comprise complex biological and mechanical engineering systems that must worktogether efficiently. An underperforming mechanical system will limit the AD/biogas system’sability to perform the necessary biological processes. Similarly, a biological system failure meansthat even the best mechanical system will only be useful for moving ineffective biomass out ofthe reactor vessel, requiring a restart of the operating system.The goal of this Operator Guidebook is to increase understanding of effective operations andmaintenance (O&M) for the performance of these complex systems. This document is intendedto be a resource for AD/biogas system owners, managers, operators, and other projectstakeholders to educate, maintain, or improve effective operation. Operators can also maximizeprofitability by increasing biogas yield, quality, utilization, and operating uptime whileminimizing O&M expenses and avoiding common difficulties that can lead to lowerperformance, shutdown, and community challenges such as odors. The Operator Guidebookaddresses fundamental questions about “what it takes” to successfully operate and maintain anAD/biogas system on an agricultural operation.Effective operator training can increase AD/biogas system productivity and operating efficiency.Training can help avoid some of the common challenges that, if not actively managed, couldlead to unintended AD/biogas plant shutdowns, neighbor complaints, or
Guidebook were collectively prepared to improve the successful development, implementation, and operation of on-farm AD/biogas systems. While this Operator Guidebook addresses numerous aspects of AD/biogas systems, it is not possible to cover every component, as there are many different types of systems, and each AD/biogas project is unique.
Rapid Flow, Titration, Turbidimetry, Ultraviolet- Visible Spectroscopy (UV/VIS) Parameter/Analyte Water pH EPA 150.1 Turbidity EPA 180.1 Calcium EPA 200.7 Iron EPA 200.7 Magnesium EPA 200.7 Potassium EPA 200.7 Silica, Total EPA 200.7 Sodium EPA 200.7 Aluminum EPA 200.8 Antimony EPA 200.8 Arsenic EPA 200.8 .
drive un 4,00 208,17 832,68 lote: 003 - lote 003 1 12807 bateria 45 amp para uno fire moura un 1,00 280,35 280,35 lote: 003 - lote 003 2 12885 filtro p71 para uno fire tecfil un 1,00 39,42 39,42 lote: 003 - lote 003 3 12809 Óleo motor 10w40 para uno fire lubrax un 1,00 70,10 70,10 lote: 003 - lote 003 4
EPA Test Method 1: EPA Test Method 2 EPA Test Method 3A. EPA Test Method 4 . Method 3A Oxygen & Carbon Dioxide . EPA Test Method 3A. Method 6C SO. 2. EPA Test Method 6C . Method 7E NOx . EPA Test Method 7E. Method 10 CO . EPA Test Method 10 . Method 25A Hydrocarbons (THC) EPA Test Method 25A. Method 30B Mercury (sorbent trap) EPA Test Method .
vii References The following resources were used in producing this manual: EPA: Package Treatment Plants MO-12, EPA 430/9-77-005, April 1977 EPA: Summary Report: The Causes and Control of Activated Sludge Bulking and Foaming, EPA 625/8-87/012, July 1987 EPA: Manual: Nitrogen Control, EPA 625/R-93/010, September 1993 EPA: Handbook: Retrofitting POTWs, EPA 625/6-89/020, July 1989
This quality assurance project plan (QAPP) is consistent with EPA Requirements for Quality Assurance Project Plans (EPA QA/R5, 2001, EPA/240/B-01/003); EPA Guidance for Quality Assurance Project Plans for Modeling (EPA QA/G-5M, 2002, EPA/240/R-02/007) and EPA
Mercedes-Benz Actros I/MP2/MP3, Axor I/II 400 mm 1 9735 003 006 LuK 640 3006 18 Mercedes-Benz Actros I/MP2/MP3, Axor I/II 430 mm 9736 009 210 LuK 343 0192 10 Mercedes-Benz Actros MP2/MP3, Axor I/II, Atego I 430 mm 1 9735 003 292 LuK 643 3292 00 Mercedes-Benz Atego I/II, LK/LN2, Vario 360 mm 1/² 9735 003 005 LuK 636 3005 09 Mercedes-Benz Axor I/II, Atego I/II 400 mm 1/² 9735 003 015 LuK 640 .
EPA Method 7E –NO, NO 2, NOx Yes EPA Method 8 –SO 2, SO 3 Yes EPA Method 10 –CO Yes EPA Method 11 –H 2 S ( 50 ppm Yes EPA Method 16 –TRS Yes, including mercaptans and other reduced sulphurs EPA Method 18 –VOC’s Yes EPA Method 26 –HCl, HF Yes EPA CTM 027 –NH 3 Yes. ADVANTAGES OF FTIR
United States U.S. EPA EPA 832-R-95-003 &EPA Environmental Protection 401 M Street SW June 1995 Agency Washington, DC 20460 A U.S. Department National Renewable NREL/TP- 430-7974 of Energy Energy Laboratory DE95009216 Golden, CO 80401 Case Studies in Residual Use and Energy Conservation at Wastewater Treatment Plants Interagency
