Manure Digesters
Background Information

Introductory/Overview Information: Anaerobic Digestion & Biogas

AD101: An Introduction to Anaerobic Digestion. Octaform Systems, Vancouver, BC. Document provides a general overview of the anaerobic digestion industry with a specific focus on key areas of growth. Documenting biogas in various regions internationally, this report provides a current synopsis of agricultural anaerobic digestion around the world. This paper examines the key firms, tank technology, funding initiatives, and overall factors affecting the biogas industry in its current markets.

Anaerobic Digestion Basics (2007)  OMAFRA. Fact sheet for basic, general information about anaerobic digestion technology.

Beginners Guide To Biogas; Renewable Energy; Detailed information about anaerobic digestion; Biogas Wikispaces; Paul Harris, U. of Adelaide SA 5005, Australia - Tel.: +61 8 8303 5597; Fax:  +61 8 8303 4364 - excellent background material on anaerobic digestion / biogas issues.

An Introduction to Anaerobic Digestion of Organic Wastes (2003) [389 KB pdf]; Fabien Monnet, Remade Scotland; Introduction, AD process information, by-products, types of facilities; advantages & disadvantages of AD, feedstocks, policy, legislation, regulation.

1) Biogas Digest Vol I - Biogas Basics;  [640 KB pdf]
2) Biogas Digest Vol II - Application and Product Development  [971 KB pdf]
3) Biogas Digest Vol III - Costs & Benefits [279 KB pdf]
4) Biogas Digest Vol IV; Country reports [241 KB pdf]; Deutsche Gesellschaft für Technische Zusammen-arbeit (GTZ) GmbH, Dag-Hammarskjöld-Weg 1-5, 65760 Eschborn, Germany; Telefon +49 6196 79-0; Telefax +49 6196 79-1115;   GATE (German Appropriate Technology Eco-efficiency Program). Biogas plants constitute a widely disseminated branch of technology that came into use more  than 30 years ago in developing countries. There are hundreds of thousands of simple biogas plants now in operation, and each one of them helps to improve the living conditions of people in rural areas. Biogas systems are an efficient way of dealing with organic waste, dung and crop residues while making optimal use of their energetic as well as nutrient content.   View/download pdf summary file (1828 KB)  - excellent overview of biogas plant design criteria.

Anaerobic Digestion Of Agro-Industrial Wastes: Information Networks Technical Summary on Gas Treatment (2000) [157 KB pdf]; AD-NETT Project FAIR-CT96-2083 (DG12-SSMI). Technical summary on gas treatment in relation to anaerobic digestion (AD) deals with the treatment processes for biogas in all stages of AD. Three major topics are discussed: - the treatment of raw biogas in order to produce a biogas quality which is according to the required standards for driving gas engines or gas fired boilers; - the treatment of flue gasses produced by gas engines or gas fired boilers in order to meet the emissions standards in a certain country; - the upgrading of biogas to natural gas quality or a required synthesis gas quality by the removing of macro components like CO2.

AgStar Handbook (EPA-430-B-97-015) July 1997; [Eds: K.F. Roos and M.A. Moser], US EPA Methane AgStar Program. All chapters & appendices available for download as PDF files;  This handbook is for livestock producers, developers, investors, and others in the agricultural and energy industry that may consider biogas technology as a livestock manure management option. The handbook provides a step-by-step method to determine whether a particular biogas recovery system is appropriate for a livestock facility.

Agricultural Biogas Casebook 2004 update [2252 KB pdf]. Joseph Kramer, Resource Strategies Inc., 22 N. Carroll St., Suite 300, Madison, WI 53703 608-251-2260; The purpose of this casebook is to provide a picture of the current state of on-farm anaerobic digester (AD) use in Illinois, Indiana, Iowa, Michigan, Minnesota, Ohio and Wisconsin in the spring of 2002.  The summary information provided in these profiles can help those considering using AD technologies to make informed choices and provide a general improvement in implementation efficiency and operator success. Agricultural Biogas Casebook (Sept 2002) [905 KB pdf]; Managing Manure with Biogas Recovery Systems: Improved Performance at Competitive Costs [4443 KB pdf] US EPA Methane AgStar Program - 8-page overview.

Methane Generation From Livestock Waste (1997); Energy Management in Agriculture Pub. #AE-105; Don D. Jones, John C. Nye and Alvin C. Dale Department of Agric. Eng., Purdue Univ., West Lafayette, IN 47907- Advantages. The main one is that a useful end-product, methane gas, is produced. Also, the odor potential of a well digested livestock waste is considerably reduced. Although digested waste has slightly less fertilizer value than non-digested waste, it is more readily available to plants. It is simply converted to a more useful form.   Disadvantages. There are several that must be carefully considered in assessing the potential of on-farm methane generation.

Biogas processes for sustainable development (1992), Uri Marchaim, MIGAL Galilee Technological Centre Kiryat Shmona, Israel (ISBN 92-5-103126-6)FAO; comprehensive review. Full Report [1499 KB pdf].

Fertilizer Value and Weed Seed Destruction Potential of Digested Manure (June, 2003) [51 KB pdf]; Deborah Allan, Dept of Soil, Water & Climate, U. of Minnesota; Elizabeth Katovich, Dept of Agronomy & Plant Genetics, U. of Minnesota; Carl Nelson, The Minnesota Project. Results to date indicate the following key preliminary conclusions: (1) stored, digested manure can result in crop yields equivalent to undigested manure or fertilizer when applied at similar nitrogen rates, while simultaneously allowing the capture of bioenergy; and (2) the digestion process does not appear to significantly destroy weed seed viability, although germination times may be impacted.

Feedstocks for Anaerobic Digestion [216 KB pdf] (1998). Steffen, R.; Szolar, O. and Braun, R., Inst. for Agrobio-technology Tulln, U. of Agricultural Sciences Vienna. The feedstocks for anaerobic digestion considerably vary in qualitative and quantitative composition, homogeneity, fluid dynamics and biodegradability. Frequently wastes contain numerous disturbing and inhibiting components. Among the most unwanted components are straw, wood shavings, sand, glass, metals and plastics. Since such matter often causes process failures, more emphasis should be drawn to avoid these components upstream of the digesters. Inhibitory components, metabolites and products like volatile fatty acids, ammonia and H2S have to be carefully controlled, especially using chicken manure or, in some cases, pig slurry.

Selecting a Digester System

1. Considering an Anaerobic Digester?  Steps to Take and Contacts to Make (G-86). [32 KB pdf] Jeannie A. Leggett, Extension Assistant, Dept of Agric. & Biol. Eng., Robert E. Graves, Professor of Agricultural Engineering,  Penn State University. Anaerobic digesters are custom designed and built for your farm needs. They should be designed by an experienced designer who has already worked through the common problems associated with anaerobic digestion. Currently, biogas production is best suited for farms that handle large amounts of slurry manure with little or no bedding. A common rule of thumb for economical operation of an anaerobic digester is manure from a minimum of 200 dairy cows or an equivalent amount of swine or poultry manure.
   
2. A "Self Screening" Assessment Method: Determining The Appropriateness Of A Manure Digestion System On An Animal Production Facility, Richard Mattocks, Environomics, Riverdale, NY.  An approach has been developed with the intent of providing animal producers tools to “self-screen” or self-assess the potential viability of installing manure digestion system systems. Producers interested in exploring the option of installing a digestion system will be able to: 1. Learn how a system would benefit the facility; 2. Gauge the ranges of system installation and operating costs; 3. Identify equipment and materials currently on the farm which will be usable; 4. Assess, through a simple weighted checklist, the likelihood of successfully installing a system. SEE:   updated 2005 assessment form.
   
3. Anaerobic Digestion Good Practice Guidelines [1562 KB pdf]. Renewable Energy Association, 17 Waterloo Place, London SW1Y 4AR;  Anaerobic digesters produce conditions that encourage the natural breakdown of organic matter by bacteria in the absence of air. Anaerobic digestion (AD) provides an effective method for turning residues from livestock farming and food processing industries into:  1. Biogas (rich in methane) which can be used to generate heat and/or electricity; 2. Fibre which can be used as a nutrient-rich soil conditioner, and, 3. Liquor which can be used as liquid fertiliser.
   
4. AgStar Handbook, EPA-430-B-97-015, July 1997 [Eds: K.F. Roos and M.A. Moser]. US EPA Methane AgStar Program; all chapters & appendices available for download as PDF files. This handbook is for livestock producers, developers, investors, and others in the agricultural and energy industry that may consider biogas technology as a livestock manure management option. The handbook provides a step-by-step method to determine whether a particular biogas recovery system is appropriate for a livestock facility. See Chapter 2:  Preliminary Screening for Project Opportunities.
   
5. Quality Function Deployment as a Decision Support Tool for the Sustainable Implementation of AD facilities (2001). Steven Trogisch, Profactor GMBH, Energy and Environmental Technologies, Wehr-grabengasse 1– 5, A-4400 Steyr, Austria.  Using the Quality Function Deployment (QFD) methodology as basis, a decision support tool has been developed in order to assess the sustainable integration of AD facilities in different European countries. The tool is based on Implementation criteria that has been set up by various experts in the different areas concerning AD.
   
6. Dairy Waste Anaerobic Digestion Handbook: Options for Recovering Beneficial Products From Dairy Manure  [June 2001][1700 KB pdf]. Dennis A. Burke, Environmental Energy Company, 6007 Hill St., Olympia, WA 98516. The rapid growth in the size of dairy operations has resulted in new laws and regulations governing the handling and disposal of manure. Requirements for nutrient management plans, manure solids disposal, and odor control make it necessary that new manure management approaches be considered. One of the more promising methods is anaerobic digestion - includes review of various manure processing technologies; excellent discussion of factors impacting on the digestion process.   - excellent overview of various digester designs and factors impacting on digestion processes.
   
7. Biogas Applications for Large Dairy Operations: Alternatives to Conventional Engine-Generators [294  KB pdf] March 7, 2001. Darrell T. Mears, Optimum Utility Systems, P.O. Box 610, Langhorne, PA 19047; FOR: Cornell Coop. Ext. Assoc., 401 North Main St., Warsaw, NY 14569.  This report examines biogas processing and alternatives to conventional engine-generators.  The alternatives include hot water boilers, absorption chillers, radiant heaters, and other technologies that may be adapted to biogas service; includes excellent overview of technology + list of product suppliers.
   
8. How to Select an Alternative Manure Treatment System [35 KB pdf] Kelly Zering, Dept. of Agricultural and Resource Economics, North Carolina State U.  Document provides a brief review of the economics of manure management and some steps for pig producers to take in selecting alternative manure management systems.
   
9. Anaerobic Digesters and Methane Production: Questions that need to be asked and answered before investing your money [949 KB pdf] (2001). U. of Wisconsin Extension.  The purpose of this publication is to provide brief answers to the common questions farmers often ask about anaerobic digestion and methane generation.
   
10. Anaerobic Digestion of Animal Wastes: Factors to Consider (Farm Energy Technical Note).  John Balsam, National Sustainable Agriculture Information Service. This publication provides an introduction to the technology, with discussion of the digestion process; production, uses, and risks of bio-gas; digester design considerations; and system costs. Useful tables and further resources are included. 
    
11. “Self Screening” Assessment: “The Appropriateness of a Community Manure Food Waste Digestion System” [442 KB pdf] (Aug. 2003). Richard Mattocks, RCM Digesters, Inc., Riverdale, NY for Agricultural Utilization Res. Inst. (AURI), Crookston, MN. A certain minimum number of animals will be required to participate for the Community Manure Food Waste Digestion Facility to be economically viable. A rule of thumb is to have manure from the equivalent of 6000 mature Holsteins in a 5 mile driving range of the centralized facility.
    
12. Is a digester right for your farm? (Feb. 2005)[423 KB pdf].  Mark Moser, RCM Digesters - a scoring sheet to guide farm owners thinking about a digester and sees these characteristics of successful projects.
    
13. Funding On-Farm Biogas Recovery Systems A Guide to Federal and State Resources [653 KB pdf] - AgSTAR Program - this guidebook is not intended to provide an exhaustive list of all state and federal funding programs; instead, it is intended to provide a snapshot of the broad range of opportunities that exist for project funding.
    
14. Anaerobic Digester Systems for Mid-Sized Dairy Farms [740 KB pdf] (2005). Philip R. Goodrich,Dept of Bioproducts & Biosystems Engineering, U. of Minn.; The Minnesota Project.  Six options for anaerobic digestion of animal manure on mid-sized dairy farms in Minnesota have been presented to provide dairy farm operators with information needed to make decisions about odor control and manure management technology. Information for each option is presented with schematics of the system, an explanation of how the system functions, the environmental benefits and lessons learned from other similar digesters. Capital costs for the installation of the digesters and yearly costs are presented. The expected benefits from odor control and use of separated solids are presented for a 100-cow dairy.

Background Information

Biogas Forum (Switzerland) - information on European biogas technology companies and background information on the topic

Balancing phosphine in manure fermentation (1997) [94 KB pdf]. F. Eismann¹, D. Glindemann¹ and A. Bergmann¹, P. Kuschk²; ¹U. of Leipzig, Inst. for Animal Hygiene & Vet. Public Affairs, Semmelweisstrasse 4, 04103 Leipzig, Germany;  ²Ctr for Env. Res. Leipzig-Halle Ltd., Section for Remediation Research, Permoserstrasse 15, 04318 Leipzig, Germany - J. of Env. Sci. and Health Part B: 32 (6): 955-968  - The evolution of phosphine gas during the anaerobic batch fermentation of fresh swine manure was detected and correlated to the production of methane and hydrogen sulphide. A close temporal relationship between phosphine liberation and methane formation was found - manure has to be considered more as a sink of phosphine rather than a phosphine-generating medium.

Latest Progress In Anaerobic Digestion, by Philip Lusk, Resource Development Associates in Washington, D.C. - From BioCycle Magazine, July 1999, Page 52 - Systems recovering biogas and processing organic residues move forward after a slow start, as economics improve and manure management regulations get tougher. Compared to countries like Germany and Denmark, the United States and Canada have a long way to go in creating the fundamental policy incentives and regulatory mandates that will encourage market development for anaerobic digestion (AD).

Methane Recovery from Animal Manures: The Current Opportunities Casebook (Sept. 1998) [2794 KB];  NREL/SR-580-25145; by Philip Lusk, Resource Development Associates, Washington, DC on behalf of National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393 - Anaerobic Digestion benefits farmers monetarily and mitigates possible manure pollution problems, thereby sustaining development while maintaining environmental quality. Moreover, rural economic development will benefit from the implicit multiplier effect resulting from jobs created by implementing digester systems. Promising future waste-to-profit activities may add to the economic performance of AD. New end-use applications, which provide added value to co-products, are discussed.

Methane recovery from manure: Control odor and produce energy (Fall 1999). Paul Miller, USDA-Natural Resources Conservation Service, Des Moines, IA - Iowa Manure Management Group, - It might surprise a lot of people, but manure can be nearly odor free. And it could make you money! New advances in methane digestion technology are finding success in Iowa. Several different types of anaerobic digesters have recently been installed in Iowa with assistance from the USDA-Natural Resources Conservation Service (NRCS) and AgSTAR. AgSTAR is a voluntary program of the U.S. Environmental Protection Agency that is designed to encourage the widespread use of livestock manure as an energy source.

Biological Manipulation of Manure: Getting What You Want from Animal Manure (G87) [89 KB pdf]. Jeannie A. Leggett, Ext. Assoc., Dept of Agric. & Biol. Engineering, Les E. Lanyon, Assoc. Prof. of Soil Fertility, Dept of Agronomy, Robert E. Graves, Prof.,  Agric. Engineering, Dept of Agricultural and Biological Engineering, Penn State University - Because manure is energy-rich and alive with microorganisms, planning for microbial change can help farmers get what they want from animal manure. Factors, such as the environment for microbial growth, can be controlled and used as a tool to put the desirable microorganisms to work. Understanding how to "feed and care for" the desirable microorganisms can reduce odor and nuisance problems associated with manure storage and handling systems and also provide a more desirable end product.

Anaerobic Digestion: Biogas Production and Odor Reduction from Manure (G77) [94 KB pdf]. Jeannie Leggett, Robert E. Graves, Les E. Lanyon, Department of Agricultural and Biological Engineering, Penn State U.  Controlled anaerobic, or oxygen-free, digestion of animal manure is a way to treat manure to prevent foul odor production while generating a usable energy product. Under the right conditions, liquid manure will break down into biogas and a low-odor effluent. Biogas can be burned to produce heat, electricity, or both.

Using fate of Incoming Solids to Measure Manure Digester Performance. R.P. Mattocks (Environomics Inc.) and Mark A. Moser (RCM, Inc.). Investors should expect manure designers to compare outputs from their manure digestion systems to these examples. This paper presents results from two dairy manure mesophilic plug flow digestion systems which should be used as benchmark values against which other similar system should compare.

Summary of performance of several digesters. Richard Mattocks, Environomics Inc., Riverdale, NY, AA Dairy; Haubenschild Dairy; Swine USA; Colorado Pork.

Manure Digestion System: Overview Information. Agricultural Utilization Research Institute (AURI), Crookston, MN - Contact Dan Lemke; Learn more about evaluating the benefits of an on-farm digester as a means of manure processing. A check list for producers to use to determine if a digester is a viable option for them is provided. View/Download description [263 KB pdf].

Converting Poultry Manure to Other Products. Poultry Manure Management And Utilization Problems And Opportunities - Bulletin 804 - Ohio State U. - Microbial conversion of poultry manure to partly oxidized products that have more desirable characteristics has been undertaken in recent years with methods that exert some control over the biological processes involved. Such products may be more desirable because they have greater stability, contain more organic nitrogen, have fewer odors, and may have wider usage than plant fertilizer. These products are produced by controlled composting but require poultry manure to be mixed with a carbon source which provides energy for the microorganisms and a physical matrix for oxygen penetration into the fermenting mixture.

Gas production from pig manure fed at different loading rates to polyethylene tubular biodigesters. Bui Xuan An and T.R. Preston, University of Agriculture & Forestry, ThuDuc, HoChiMinh City, Vietnam; Livestock Research for Rural Development, Volume 11, Number 1, 1999. Pig manure was fed at different loading rates (0.66, 1.33, 2, 2.66 kg dry matter/m³digester liquid volume/day) to four plug-flow plastic tube biodigesters of 1.5 m³ liquid volume. The design was a 4*4 Latin square arrangement. The hydraulic retention time was 30 days and each experimental period was 8 weeks, the first 7 weeks for adaptation to the chosen loading rate and the last week for measurements.

Effect of length: diameter ratio in polyethylene biodigesters on gas production and effluent composition Livestock Research for Rural Development 17 (11) 2005. San Thy et al., CelAgrid, UTA Cambodia.  The treatments - Length and diameter ratio and retention time  of plastic plug-flow biodigesters.  The design was a single changeover with experimental periods of 40 days on each retention time. The length: diameter ratios were 8:0.6, 5:0.6, 3:0.6 and 2:0.6m with hydraulic retention times of 10 or 20 days.  For each retention time, the amount of manure (DM) was kept constant by adding water according to retention times. The manure solid concentration in the influent for 10 days retention time was 4 % and  for 20 days was 8 %. Biogas production as liters per 100 litres liquid volume biodigester, and ammonia concentrations in effluent, did not differ between different length:diameter ratios nor between retention times.

Biological Treatment of Dairy Manure Using Sequencing Batch Reactors: Improving Profitability Through Innovative Design. Paul C. Reeves, Kerstin P. Johnson, and Carlo D. Montemagno, Dept of Agric. & Biol. Eng., Cornell U.   The Sequencing Batch Reactor (SBR) displays great potential for increasing the profitability of the dairy industry by eliminating environmental problems associated with manure disposal. Recent trends in dairy farming have demonstrated how higher profitability can be achieved through greater herd sizes.

Why Digesters Make Dollar Sense Now BioCycle, March 2001. Richard Mattocks, Environomics, Inc.; Two important principles should not be overlooked in digester designs: (1) First order of business on the farm is production of animal products; the digester is secondary, and (2) Projects that generate revenue command more management attention and respect than those which lose money or are dependent on free money.

Environmental Aspects of Biogas Technology [78 KB PDF]. Barbara Klingler, German Biogas Association. Biogas technology contributes in a wide range of aspects and effects to the environment. The major effect for farmers is the improved quality of anaerobically treated manure. This results in a better handling (less clogging), increased ammonia content, increased possibility to apply on demand of the plants, less odour and potential decreased use of mineral fertilizer and pesticides. Anaerobic treatment and gas use contributes to the reduction of greenhouse gases. Biogas is a competitive energy source and protects limited fuel resources. 

Legislation in different European countries regarding implementation of anaerobic digestion - Technical summary [85 KB pdf]. Åke Nordberg, Swedish Inst. of Agric. Eng., Box 7033, SE-750 07 Uppsala, Sweden - ake.nordberg@jti.se; Legislation covering agricultural, environmental and energy issues affect the implementation of anaerobic digestion.  Survey of policies on renewable energy with impact on biogas implementation for 12 different EU-countries.

Process design of agricultural digesters  [245 KB pdf]. Arthur Wellinger, Nova Energie GmbH,Elggerstrasse 36, 8356 Ettenhausen, Switzerland; Tel. 052 368 34 70; Fax 052 365 43 20; office.ettenhausen@novaenergie.ch  - The three areas of interest to most potential purchasers of anaerobic digesters for use on farms are pollution control (reduction of methane emission odour control), improvement of manure quality as a fertiliser and energy production. With energy production as the major objective there is likely to be more technical equipment and design needed for producing a maximum amount of gas and its efficient utilisation than is needed for a digester which is designed primarily for pollution control.

Thermochemical Conversion Of Swine Manure To Produce Fuel And Reduce Waste (1999); Yuanhui Zhang, Gerald Riskowski, and Ted Funk, 332 Agricultural Engineering Sciences, 1304 W. Pennsylvania Ave, U. of Illinois - Urbana-Champaign, Urbana, IL 61801;  The ultimate goal of this research is to develop an environmentally- and economically - sound technology to manage swine manure efficiently. The technology is the thermochemical conversion (TCC) process of swine manure.  Objectives:  1) Exploring operation parameters that affect thermochemical conversion of swine manure based on oil production rate and waste reduction. 2) Determining reduction rate of swine wastewater through the TCC process. 3) Determining production rate of liquid fuel through the TCC process. 4) Examining fertilizer/soil conditioner value of solids residue from the TCC process and its application possibilities. View/Download Report [425 KB pdf].

Wastewater Treatment Options for the Biomass-To-Ethanol Process (1998) [59 KB pdf] Merrick & Company for National Renewable Energy Laboratory (NREL) (# AXE-8-18020-01) - evaluation of Waste Water Treatment Alternatives for various ethanol manufacturing processes. Three Lignocellulosic Biomass-to- Ethanol processes are currently under development by NREL.

Evaluation of H2S Scavenger Technologies (1994) [185 KB pdf]; A. J. Foral and B. H. AI-Ubaidi, The M.W. Kellogg Company, 601 Jefferson Ave., PO Box 4557, Houston, Texas 77210-4557 - Objective was to establish the cost for removing Low level concentrations of hydrogen sulfide from a natural gas stream using commercially available scavengers. The scavengers were used in a batch process on a throw-away basis. No attempt was made to regenerate the scavenger in place. 

The PRIME Project. Planned Integrated Ethanol-Feedlot-Methane System in South Dakota (16 KB pdf). The system, under development by PRIME (Pierre Renewable Integrated Meat & Energy) Technologies, LLC, would have integrated an enclosed custom cattle feedlot, an anaerobic digester, and a modified ethanol unit; to be a "closed-loop" system that produces beef, fuel ethanol, methane, and biochemical fertilizers. Each of the component technologies proposed is well proven on a "stand-alone" basis.  White paper on the Justification For Federal Support Of Farmer-Owned Value added Processing Complexes (April 2001); Integrated Beef and Energy Complex  [264 KB pdf]; Dakota Value Capture Cooperative (DVCC) - innovative agriculture producer-based co-op established to own and operate the PRIME facility at Pierre, SD, thus keeping farm & ranch families a viable entity in production agriculture. Final Activities Report [358 KB pdf]; Note - The PRIME project was cancelled due to financing issues in Oct. 2002.

Evaluation of Two-Stage Anaerobic Sequencing Batch Reactor Systems for Animal wastewater Treatment (2000). R.H. Zhang, J. Tao, Biol. & Agric. Eng. Dept, U. of California, Davis, California; P.N. Dugba, Murphy Family Farms, Inc.; Trans. ASAE 43(6): 1795-1801; The thermophilic-mesophilic ASBR system (II) had a better performance, with higher solids (TS and VS) reduction and biogas production rate than the mesophilic-mesophilic ASBR system (I) at the same VS loading rates; anaerobic treatment using both anaerobic treatment systems tested effectively reduced the generation of odorous sulfur gases during the manure storage.

Anaerobic Digestion: Holistic Bioprocessing of Animal Manures (2000) [50 KB pdf]; Ann C. Wilkie, Soil and Water Science Dept, U. of Florida, Gainesville, FL 32611-0960; Tel: (352)392-8699 Fax: (352)392-7008; The optimal manure management system should provide a sustainable approach designed to minimize environmental impacts and maximize resource recovery. Anaerobic digestion, under controlled conditions, offers a holistic treatment solution that controls odors, produces usable energy, minimizes environmental impact from waste emissions, and maximizes fertilizer and water recovery and reuse.

Anaerobic digestion, storage, oligolysis, lime, heat and aerobic treatment of livestock manures  (2003) (Final report) [970 KB pdf]. The Scottish Government; Objective of this study was to explore alternative treatment strategies for the prevention of water pollution from faecal micro-organisms originating from livestock manures.

Methane Generation From Human, Animal, And Agricultural Wastes (1977) [658 KB pdf]. Report of an Ad Hoc Panel of the Advisory Committee on Technology Innovation,  National Research Council, NATIONAL ACADEMY OF SCIENCES, Washington, D.C.,1977. Study is written as a companion piece to an ACTI report on renewable resources of energy, and technologies for their exploitation, in rural areas of developing countries. The generation of methane from human, animal, and agricultural wastes for use in these rural areas appeared to warrant special, intensive analysis in a publication of its own.

Thermophilic Anaerobic Digestion With Ultrafiltration For Dairy Manure (2003) [596 KB pdf]. David S. Vogel (Thesis), Civil & Env. Eng., Marquette U., Milwaukee, WI - purpose of this study was to determine volatile solids (VS) destruction and biogas production from pilot-scale thermophilic anaerobic digestion with ultrafiltration (TADU) utilizing dairy manure as the substrate.

Anaerobic Digestion Of Biodegradable Organics In Municipal Solid Wastes [pdf] (M.Sc. Thesis, May 2002) - SHEFALI VERMA, Dept of Earth & Env. Eng., Columbia University - study examined in depth the current status of the anaerobic digestion technologies for the treatment of the organic fraction of municipal solid wastes (MSW); review of systems in operation worldwide was made, including types of process design and their engineering and environmental performance.

Biogas Energy Potential from Agricultural & Food Wastes

Biogas Energy Potential in Alberta. Alberta Agric. & Rural Development. Includes tables showing inventory of livestock, crops and municipal wastes, as potential feedstocks for Co-digestion systems.

Food-Based Inputs for Biogas Systems in Ontario: How Much is Out There?  OMAFRA. In the spring for 2008, the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) commissioned a report to investigate the quantity, quality and current uses of various food-based materials that could be used as biogas system inputs. The results are reported in the Final Report for the Study of Food-Based Inputs for Biogas Systems in Ontario

Dry Fermentation / Digestion

Dry Fermentation Of Agricultural Substrates (Oct. 2003) [283 KB pdf]; F. Kaiser, V. Aschmann, M. Effenberger and A. Gronauer - Pp. 325-332, 9th Int'l  Animal, Agric. & Food Processing Wastes Proc. of the 12-15 Oct. 2003 Symp. (Research Triangle Park, NC USA), ASAE Pub. 701P1203, ed. Robert T. Burns; challenge to adapt anaerobic fermentation technologies for the direct treatment of organic waste with solid contents of 20 % and more; batch fermentation system has been proposed where the input is stacked up in a gas-tight container and left there for fermentation for about 50 days, while being sprayed intermittently with a heated, circulating inoculate.

Dry Nonheated Anaerobic Biogas Fermentation Using Aged Beef Cattle Manure (2002) - Parker, D.,  Williams, D. (WTAMU) Cole, Noel (USDA/ARS) Auvermann, B - TAES Rogers, W - WTAMU - Biogas production at beef cattle feedlots is hard to justify because of the large amounts of dilution water required and the high cost to design and operate conventional water-based digestion systems. Laboratory and field experiments were conducted to determine the feasibility of producing biogas using "dry" aged beef cattle manure scraped from open-lot feedyards;research demonstrates that biogas can be produced in below-ground digesters using aged beef cattle manure if the solids content is less than or equal to 40 percent.

New BEKON Biogas technology for dry fermentation in batch method [282 KB pdf]; Peter Lutz, BEKON Energy Technologies GmbH & Co. KG, Nikolastraße 18, D - 84034 Landshut; Tel.: +49 (0)871 14383 - 0; Fax: +49 (0)871 14383-29; the recently patented BEKON dry fermentation process can produce methane from organic matter with a high content of dry matter (up to 50 %).

Biodegradability of Dairy Cattle Manure under Dry Anaerobic Fermentation Process (June 2003) [150 KB pdf]; T.K. Bhattacharya, T.N. Mishra, Inst. of Engineers, India, Vol 84. Anaerobic batch fermentation of undiluted (dry) dairy cattle manure under psychrophilic, mesophilic and thermophilic conditions was studied to establish its biodegradability and compare the feasibility with conventional process (diluted manure). low biodegradability of undiluted manure at 55°C was due to process failure that occurred because of excessive washout of carbon dioxide during initial phase of fermentation resulting in drop in pH below the toxic limit of 6.0. Study suggests that dry anaerobic fermentation process may be a promising alternative to the conventional process in mesophilic temperature conditions. 

Demonstration Of Biogas Production Using Low Moisture Content beef Cattle Manure (2000) [432 KB pdf],  David Parker, Box 60998, West Texas A&M U., Canyon, TX 79015; tel:(806) 651-5281; Fax: (806) 651-2504 - A research and demonstration project was performed to evaluate biogas production at ambient temperatures using beef cattle manure scraped from open lot feedyards;  research and demonstration project demonstrated that biogas could be produced in landfill cells using beef cattle manure scraped from open lots. However, further work is required before biogas production with beef cattle manure will be feasible. 

Fixed Film AD Systems

Anaerobic Digestion of Flushed Dairy Manure [322 KB pdf] (2003). Ann C. Wilkie, Soil and Water Science Dept., U. of Florida, Gainesville, FL . Large volumes of flush water in flushed dairy systems means that conventional AD using complete-mix or plug-flow technologies is neither practical of economical- recommending fixed-film digester.

Reducing Dairy Manure Odor And Producing Energy [182 KB pdf] (2000). Ann C. Wilkie, Soil and Water Science Dept., U. of Florida, Gainesville, FL.  A state-of-the-art, fixed film anaerobic digester — designed specifically to meet the needs of the typical Florida dairy farm — has been installed at the Institute of Food and Agric. Sci. Dairy Res. Unit (DRU) at the U. of Florida.  The financial attractiveness of on-farm anaerobic digestion is likely to improve considerably as environmental concerns assume greater importance. A complete assessment of economic feasibility must take account of all avoided costs and the value of intangible environmental externals, such as odor control and reduction of volatile emissions.

Methane Production from a Pilot-Scale Fixed-Film Anaerobic Digester and Plug-Flow Digester Loaded with High-Solids Dairy Manure (19 KB pdf). Stephen Hoyt, Project Engineer, The DUBARA Co., Castleton, New York 12033 for Vermont Department of Public Service -  Three pilot-scale anaerobic digesters (two of a unique fixed-film design, of which one was fed micronutrients, one not, and an identically sized plug-flow digester, which served as the control) were monitored for methane production as a comparative indication of performance... Average methane production at 5 day Hydraulic Retention Time of the fixed-film digester fed micronutrients was greater than the control by 17.65%; and the fixed-film digester not fed micronutrients averaged 14.37% more methane than the control.

Fixed-Film Anaerobic Digestion Of Separated Dairy Manure: Compost Drying Of Separated Manure Solids (2002). S.A. Weeks, Middle Grove, NY; 2002 ASAE Meeting, July 28-July 31, 2002 - Cost, effectiveness, and ease of operation of a fixed-film digester system will be evaluated. Composting/drying of separated manure solids is a concept that may prove to be of economic value to dairy operations, and a relatively simple use of energy from biogas.

Integrated Manure Management Systems Provide New Opportunities for Dairy Producers [65 KB pdf] - Michigan Milk Messenger, 20 March 2004- In spring 2004, William Bickert and his colleagues in the MSU Dept of Agric. Engin. will install the first anaerobic digester on a Michigan dairy farm in 20 years, using a fixed-film anaerobic digester.

Application of the AGF (Anoxic Gas Flotation) Process, Dennis A. Burke, Environmental Energy Company, 6007 Hill Road NE, Olympia, WA 98516 USA;  The AGF process is an improved anaerobic digestion process that uses anoxic gas (without oxygen) to float, concentrate, and return bacteria, organic acids, protein, enzymes, and undigested substrate to the anaerobic digester for the rapid and complete conversion of waste slurries to gas and soluble constituents. The process has been used to treat sewage sludge (3 to 6% solids), dairy manure (7% solids), and potato waste from french-fry and potato flake production (0.4 to 1.2% solids). [010323] 
  Summary of Env. Energy Co. Technologies [126 KB pdf] - AGF Process, Pasteurization, ClearCycle, Flotation Design, Technology Benefits, Papers.

Cyclus Envirosystems' Dairy Waste Anaerobic Digestion Technologies [32 KB pdf] Dennis A. Burke, Environmental Energy Company, 6007 Hill Road NE, Olympia, WA 98516 USA - uses anaerobic “contact” process to rapidly convert dilute waste slurries to gas.

Anaerobic Fixed-Film Digester System for Dairy Manure (2003) [658 KB pdf] Stanley Weeks, Middle Grove, NY.  Digester operation began in October, 2001, and biogas production reached a steady state level of 28 cubic feet per cow per day. Ten lab test results, over a period of 8 months, indicated a 27% reduction in volatile solids in the digester. Biogas averaged 62% methane, and hydrogen sulfide in the gas was approximately 6,000 ppm. Biogas production averaged 5.79 cubic feet per pound of volatile solids loaded, and 22 cubic feet per pound of volatile solids destroyed.

Temperature-phased Anaerobic Digestion (TPAD)

Performance of temperature-phased anaerobic digestion (TPAD) system treating dairy cattle wastes. (2003).  Shihwu Sung  and Harikishan Santha, Dept of Civil & Constr. Eng., Iowa State U., Ames, Iowa 50011-3232, USA  - Water Research 37:1628–1636] - In this study, the TPAD system operating at a retention time of 14 days was subjected to varying total solids (TS) concentrations (3.46–14.54%) of dairy cattle wastes. At TS concentrations lower than 12.20%, corresponding to system volatile solids (VS) loadings in the range of 1.87–5.82 g VS/L/day, the system achieved an average VS removal of 40.2%. The maximum VS destruction of 42.6% was achieved at a TS concentration of 10.35%. Methane recovery from the wastes was consistently within 0.21–0.22 L/g VS fed.

Comparison of temperature phased and other state of the art processes for anaerobic digestion of municipal solid waste (2000)[940 KB pdf]; Schmit, K. H., and Ellis, T.G., Iowa State U., Dept of Civil, Construction, and Environmental Engineering. Poster Proceedings of 1st World Water Congress of the Int. Water Assoc., Paris, France, July, 2000. The temperature-phased system performed comparably to other slurry processes reported in the literature with the exception that the TPAD process provides increased pathogen destruction due to the high temperature first stage. The TPAD system outperformed dry digestion processes. T he VS reduction and methane yields reported in the literature for dry digestion processes ranged from 27 to 60% and from 0.13 to 0.30 L/g VS fed, respectively.

Temperature Phased Anaerobic Digestion System Monitoring Project at Tinedale Farm - Final Report (Oct. 31, 2003)[155 KB pdf]; John F. Katers & Joe Schultz, U. of Wisc.-Green Bay - temperature-phased Anaerobic Digestion (TPAD) system was most likely to meet their short and long-term objectives. The TPAD system utilizes thermophilic temperatures in the first phase and mesophilic temperatures in the second phase. The TPAD system is patented and assigned to the Iowa State University Research Foundation, Inc. - Wisconsin Energies; AG Environmental Solutions

Aerobic Digestion

Aerobic Thermophilic Digestion for stabilising and pasteurising raw sludge. LIMUS Umwelttechnik GmbH, Eichborndamm 165, D - 13403 Berlin; Tel: +49 (0)30 40 90 09 - 0, Fax: +49 (0)30 40 90 09 22; E-Mail: info@limus.de  - The LIMUS-Biotherm-Process has been designed particularly for sludge treatment of smaller purification plants. Both digestion and safe hygienisation in one step is ensured. Thermophilic Aerobic Digestion is economically in investment, simply in operation and thus superior to other systems for a population between 5.000 and 50.000. The process is suitable also for the pre- treatment of faecal sludges.

Digestion Effects On Dewaterability of Thermophilic And Mesophilic Aerobically Digested Biosolids  (2001) [57pdf] Jianpeng Zhou et al., Environmental Eng. Program, Dept of Civil Engineering, U. of British Columbia, 2324 Main Mall, Vancouver, BC, Canada V6T 1Z4; Email: jpzhou@civil.ubc.ca-This study found that thermophilic aerobic digestion significantly deteriorated dewaterability of the secondary sludge, but had less effect on the primary and the mixed sludge. Mesophilic aerobic digestion had-gradual and continued effects that deteriorated dewaterability of all types of sludge. Sludge retention time was not a predominant factor for effects of thermophilic digestion on-dewaterability, but was important in the effects of mesophilic digestion.

Auto-ThermophilicAerobic Digestion (ATAD)

VERTAD™ –Auto-Thermophilic Aerobic Digestion: Demonstration-Scale Test Results (2002) [604 pdf]; Jeff Guild, NORAM Engineering and Constructors Ltd., et al., * NORAM Engineering and Constructors Ltd., Suite 400, 200 Granville St., Vancouver, BC, Canada, V6C 1S4; tel: 604-681-2030, Fax: 604-683-9164; VERTAD™ is an auto-thermophilic aerobic digestion process, employing a subsurface verticalreactor to aerobically digest mixed primary and secondary wastewater treatment solids. High-metabolic activity results in heat generation, which enables the production of Class A Biosolidsat short solids retention times (SRT).

2nd Generation Autothermal Thermophilic Aerobic Digestion:-Conceptual Issues and Process Advancements [414 KB pdf]. Kevin L. Staton and James E. Alleman, School of Civil Eng., Purdue U., West Lafayette, Indiana 47907-1284; Richard L. Pressley and James Eloff, Thermal Process Systems, 779 Courtney Drive, Crown Point, IN 46307-4365; Tel.: 219-663-1034; FAX: 219-663-7248;  A technical assessment of the upcoming, 2nd generation improvements being developed for, and implemented with, these ATAD systemssuch that the latter shortcomings can be obviated. In addition, the key conceptual issues with ATAD operations will be addressed, covering both design and operational details.

Autothermal Thermophilic Aerobic Digestion Research, Application & Operational Experience (Oct. 2003) [1847 KB pdf]; H.G. Kelly (Dayton & Knight Ltd); D.S. Mavinic, U. B.C., Vancouver, BC - Review of recent ATAD research, current applications & case studies presented.

Multiple-Stage Anaerobic Digestion

Influence of temperature and feeding mode on digestion and sanitation efficiency during multiple-stage anaerobic treatment of liquid dairy cattle manure. (Thesis, July 2008). Mathias Effenberger, Bavarian State Res. Center for Agric., Freising, GERMANY;  Evaluation of the performance of a multiple-stage anaerobic digestion process with respect to the degradation of organic matter and the inactivation of pathogenic and indicator organisms in liquid dairy cattle manure. During the three-stage mesophilic-thermophilic-mesophilic anaerobic treatment of liquid manure from cattle receiving a high-fiber diet, a comparably high methane yield of 0.24 m3 per kg of volatile solids was achieved. When the temperature in the first treatment stage was decreased from 38 to 20-25°C, the process stability in the thermophilic reactor was significantly improved while overall the methane yield and the reduction of indicator organisms remained essentially unchanged. Based on these findings, 2-stage thermophilic-mesophilic anaerobic digestion can be approved as a treatment technology for liquid manure to minimize the input of pathogenic and indicator organisms from livestock farming into the environment.

Co-Digestion

Feasibility of increased biogas production from the co-digestion of agricultural, municipal, and agro-industrial wastes in rural communities (2008). Tanya McDonald et al., Olds College, Olds, AB T4H 1R6, Canada. J. Env. Eng. & Sci. 7:263-273;    In rural communities, such as Olds, Alberta (population 7248) energy may be produced through anaerobic co-digestion of municipal, agricultural, and agro-industrial wastes. An inventory within a 20 km radius of Olds revealed that 291 000 tonnes of wet organic waste are generated annually (96.8% manure) with an electrical potential of 42 GWh (1 GWh = 106 kWh). Analysis of feedlot, hog, dairy and poultry manure, offal, food, grass, and biosolids identified the potential for waste blending to optimize solids content, nutrient balance, and pH level. In laboratory tests, biogas yield increased from 0.382 m3/kg volatile solid (VS) for feedlot manure alone to 0.513, 0.517, and 0.500 m3/kg VS with co-digestion of 30% hog manure, 15% offal, and 30% offal, respectively. Methane content of biogas increased from 75.8% in feedlot manure digestion to 78.8, 79.5, and 80.9% with co-digestion of 30% hog manure, 15% offal, and 30% offal, respectively.

Opportunities, Constraints, and Research Needs for Co-digestion of Alternative Waste Streams with Livestock Manure in Minnesota (Nov. 23, 2005) [pdf]- Minnesota Dept of Agriculture, Agric. Resources Management & Development Div. The purpose of this report is to identify potential waste streams in Minnesota that could be combined with manure to enhance biogas production and increase revenues of an AD system.

Environmental aspects of the anaerobic digestion of the organic fraction of municipal solid wastes and of agricultural wastes. Water Sci Technol. 2005;52(1-2):203-8. W. Edelmann (1), U.Baier (2) and H. Engel (3), (1) arbi GmbH, Baar, Switzerland, (2) HSW Wädenswil, Switzerland, (3) engeli engineering, Neerach, Switzerland - In order to get more detailed information for better decision making in future biogenic waste treatment, different processes to treat biogenic wastes in plants with a treating capacity of 10,000 tons of organic household wastes per year as well as agricultural codigestion plants were compared by life cycle assessments (LCA).

Anaerobic codigestion of hog and poultry waste. (2001). Bioresource Technology 76:165-168. Magbanua B.S.; Adams T.T.; Johnston P.; Dept of Civil Eng., Mississippi State U., MS 39762-9546, Anaerobic batch tests were performed using hog and poultry wastes in various proportions. Treatments that received both wastes produced higher yields of biogas, up to 200+/-30 mL/g volatile solids (VS) destroyed, and methane, up to 130+/-20 mL/g VS destroyed, compared to either waste alone.

Co-digestion of Manure with Industrial and Household Waste (2000) [166 KB pdf];The Kristianstad biogas plant is the first in Sweden to co-digest municipal solid waste with manure and other organic biomass to produce energy and fertiliser. In 1998, the plant handled over 70,000 tonnes of waste and produced biogas equivalent to 20,000 MWh. This project offers a sustainable solution to waste disposal problems encountered in many countries.

Co-digestion of animal manure and organic household waste: the Danish experience [513 KB pdf] Svend-Erik Jepsen, Danish Env. Protection Agency - series of 17 slides of Danish information - improved energy production over incineration approaches; Co-digestion with animal manure results in a stable process.

Anaerobic Digesters in Northern Ireland. Contact: Dr. Les. Gornall  (Dec. 1996) - some examples of mixed poultry and dairy waste digesters.

Co-Treatment of Municipal Commercial Solid Waste and Cow Manure Using a Two Phase Anaerobic Process [346 KB pdf]; A. Hanson^a, Z. Samania, G. Smith^b, Hui Wei Yua, ^aDept of Civil, Agricultural and Geological Engineering, ^bBiology and Microbiology Dept, New Mexico State Univ., Las Cruces, NM, 88003, USA.  evaluated the feasibility of producing methane gas from combined segregated municipal and agricultural waste (feedlot manure). The combination of the two wastes resulted in sufficient nutrient value and bacterial diversity to improve the biodegradability of cellulose and increase the efficiency of gas production from the combined wastes.

Feedstocks for Anaerobic Digestion (1998) [216 KB pdf]; Steffen, R.; Szolar, O. and Braun, R., Institute for Agrobiotechnology Tulln, U. of Agric. Sci., Vienna Austria - Feedstock is defined to include any substrate that can be converted to methane by anaerobic bacteria. Feedstocks can range from readily degradable wastewater to complex high-solid waste. Even toxic compounds may be degraded anaerobically depending on the technology applied.

Treatment of animal waste in co-digestion biogas plants in Sweden [521 KB pdf] - Åke Nordberg, JTI,  Swedish Institute of Agricultural Engineering, Box 7033, SE-750 07 Uppsala, Sweden - pdf presentation of biogas plants in Sweden.

Documents with Useful Facts and Figures

Methane Fuel Gas from Livestock Wastes: A Summary. James C. Barker, Biol. & Agric. Eng., NC State University, Raleigh, NC - NC Coop Ext Pub. EBAE 071-80 (Mar., 2001) Anaerobic digestion optimizing factors; digester design criteria; digester tank size; biogas properties; misc. digester operating parameters, facts & figures.

Generating Methane Gas From Manure. Charles D. Fulhage, Dennis Sievers and James R. Fischer, Dept of Agric. Eng., U. of Missouri-Columbia (Oct. 1, 1993) - data on potential gas production of swine, dairy, poultry and beef; A comparison of some typical farm heat requirements and the number of animals needed to meet these requirements; Loading rates, detention time and digester volume for swine, dairy, poultry and beef.

The use of digested slurry within agriculture [80 KB pdf] Henrik Ørtenblad, Herning Municipal Utilities, Denmark -  During the digestion of the manure at the AD plant about half of the carbon is released as methane and carbon dioxide (usually referred to as "biogas"). The dry matter content decreases and the digested slurry has a higher viscosity than cattle slurry in particular. At the same time part of the organic nitrogen, e.g. in proteins, is released as ammonium. Ammonium is directly available for the crops when it is applied to the fields. The rest of the organic nitrogen must be mineralised by soil bacteria before it is available for the crops, which is the reason why organic fertilizers have a lower efficiency compared to mineral fertilizers. 

Demonstration Of Biogas Production Using Low Moisture Content Beef Cattle Manure (may 2000)[487 KB pdf], Final Report for Western Regional Biomass Energy Program (1998-2000). Dr. David Parker, Box 60998, West Texas A&M University, Canyon, TX 79015; A research and demonstration project was performed to evaluate biogas production at ambient temperatures using beef cattle manure scraped from open lot feedyards. Laboratory experiments were conducted to measure potential biogas production rates using beef cattle manure at 21° C (70° F). 

Anaerobic digestion.  Chapter 5, Solid waste management (June 2003) [567 KB pdf]; Tjalfe G. Poulsen, Aalborg University, Sweden - energy yields from AD; process parameters; biogas production potential 

Update of the Biogas Industry in Canada (Oct, 2010) Natural Resources Canada. IEA Bioenergy Task 37.

Anaerobic Digestion - Standards and Guidelines

Anaerobic Digester  (Sept. 2009) [84 KB pdf]; USDA / Natural Resources Conservation Service Conservation Practice Standard (No.) CODE 366

Anaerobic Digestion Good Practice Guidelines [1562 KB pdf]; Renewable Energy Association, London, England EC1N 8LE. Anaerobic digesters produce conditions that encourage the natural breakdown of organic matter by bacteria in the absence of air. Anaerobic digestion (AD) provides an effective method for turning residues from livestock farming and food processing industries into:  1. Biogas (rich in methane) which can be used to generate heat and/or electricity; 2. Fibre which can be used as a nutrient-rich soil conditioner, and, 3. Liquor which can be used as liquid fertiliser.

New Regulatory Requirements for Anaerobic Digestion Facilities and Vegetated Filter Strip Systems (July 2007) OME & OMAFRA have introduced an amendment to the Nutrient Management Regulation, which sets clear standards and guidelines for the operation, design, and construction of anaerobic digestion facilities, which use off-farm waste. An exemption from approval requirements under the Environmental Protection Act (EPA) for these facilities that meet standards in the Nutrient Management Regulation has also been created. 

 A.D. Standards and Quality Control. (U.K.). Information Portal on A.D.  Gateway to information on anaerobic digestion, biogas and digestate. Information relevant to England, Scotland and N. Ireland.

Environmental Due Diligence (EDD) Of Renewable Energy Projects: GUIDELINES for Biogas Systems (Release 1.0) [384 KB pdf] (2004) United Nations Env. Programs - Environmental Due Diligence (EDD) is the collection and assessment of data relative to environmental conditions or impacts prior to a transaction to identify and quantify environment-related financial, legal, and reputational risks.

Farms seeking to insure growing number of electricity-generating manure digesters. (2007). Even for farm insurers accustomed to underwriting unique combinations of personal, commercial, and farm exposures, manure digesters pose new challenges. “Insurance companies are increasingly faced with questions on how to handle exposures generated from these systems,” says Eric Hubicki, assistant vice president for agriculture in the Chicago office of Munich Reinsurance America. “Generally,” Hubicki says,” a well-designed and managed digester will have few safety concerns.  “However, the biogas can pose health risks for workers and be explosive in confined spaces. Electrical equipment and connections in biogas exposed areas requires special adaptations to avoid spark ignition.” “If the methane is piped to a tank for storage, the operation is essentially a flammable gas compressor station like that found in the natural gas industry,” says Michael Fusselbaugh, senior vice president for business development at The Hartford Steam Boiler Inspection & Insurance Company (HSB), Hartford, Conn.

Impacts of Antibiotics and Other Inhibitors on AD Systems

The effects of certain antibiotics on biogas production in the anaerobic digestion of pig waste slurry - Bioresource Technology, April 2002, vol. 82(2): 205-208(4). Lallai A.; Mura G.; Onnis N., Dipartimento di Ingegneria Chimica e Materiali, Universita di Cagliari, Piazza d'Armi-09123, Cagliari, Italy. Antibiotics commonly used in the treatment of pigs - amoxicillin trihydrate, oxytetracycline hydrochloride and thiamphenicol - were added at different concentrations to aliquots of pig waste slurry plus anaerobic sludge in serum bottles. The biogas production and methane concentration in the headspace were monitored to determine the effect of the antibiotics on the anaerobic process. 

A system approach to biogas technology - from " Biogas technology: a training manual for extension" (FAO/CMS, 1996) - Mineral ions, heavy metals and the detergents are some of the toxic materials that inhibit the normal growth of pathogens in the digester. Small quantity of mineral ions (e.g. sodium, potassium, calcium, magnesium, ammonium and sulphur) also stimulates the growth of bacteria, while very heavy concentration of these ions will have toxic effect. For example, presence of NH4 from 50 to 200 mg/L stimulates the growth of microbes, whereas its concentration above 1,500 mg/L produces toxicity. Similarly, heavy metals such as copper, nickel, chromium, zinc, lead, etc. in small quantities are essential for the growth of bacteria but their higher concentration has toxic effects.

The action of antibiotics on the anaerobic digestion process (1996) [222 KB pdf]; Appl Microbiol Biotechnol (1996) 46: 587-592.  J. L. Sanz, N. Rodriguez and R. Amils, Dept de Biologia Molecular, Univ. AutoÂnoma de Madrid, Canto Blanco 28049 Madrid, Spain. Antibiotics can disturb the production of biogas during anaerobic digestion; study shows a systematic approach to understanding how the different bacterial populations involved in the final conversion of organic matter into methane are inhibited by 15 antimicrobial agents with different specificities and modes of action; chloramphenicol and chlortetracycline could cause the complete inhibition of the acetoclastic methanogenic archaea.

Effect of antibiotics on psychrophilic anaerobic digestion of swine manure slurry in sequencing batch reactors. (2000). D. I. Massé, D. Lu, L. Masse and R. L. Droste,  AAFC, Lennoxville, QC & Department of Civil Engineering, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5. Bioresource Technology, Vol 75(3): 205-211. The effect of antibiotics on the psychrophilic anaerobic digestion (PAD) of swine manure slurry in sequencing batch reactors (SBRs) was investigated. Six antibiotics, tylosin, lyncomycin, tetracycline, sulphamethazine, penicillin and carbadox, were individually added to the pig diet at their maximum prescribed level.

Impact and biodegradability of pharmaceuticals on the anaerobic digestion process. (2003). Fountoulakis, Michalis¹, Stamatelatou, Katerina¹, Lymberatos, Gerassimos¹, ¹ University of Patras, Dept. Chem.l Eng., Karatheodori st. 1, Patras, Greece, Greece. Soc. for Env. Toxic. & Chem. Europe - An interesting issue is whether the presence of pharmaceuticals in wastewaters has an adverse effect on a biological treatment process and specifically on the anaerobic digestion process used for sludge treatment. In this work, the effect and the biodegradability of six pharmaceuticals compounds (carbamazepine, sulfamethoxazole, propranolol hydrochloride, diclofenac sodium, ofloxacin, clofibric acid) on anaerobic digestion was studied with SMA and BMP tests.

Inhibition Of Microbial Metabolism In Anaerobic Lagoons By Selected Sulfonamides, Tetracyclines, Lincomycin, And Tylosin Tartrate (2005). Keith A. Loftin et al.,Env. Res. Ctr, Dept of Civil, Arch. & Env. Eng., U. of Missouri-Rolla, Rolla, Missouri 65409-0030, USA. Env. Toxic. & Chem. 24:(4). The introduction of antibiotics into anaerobic lagoons commonly used for swine waste treatment has the potential for negative impacts on lagoon performance, which relies on a consortium of microbes ranging from fermentative microorganisms to methanogens. To address this concern, the effects of eight common veterinary antibiotics on anaerobic activity were studied. The selected antibiotics significantly inhibited methane production relative to unamended controls, thus indicating that antibiotics at concentrations commonly found in swine lagoons can negatively impact anaerobic metabolism. Additionally, historical antibiotic usage seems to be a potential factor in affecting methane production.

The action of antibiotics on the anaerobic digestion process (1996) J. L. Sanz á N. RodrõÂguez á R. Amils Appl. Microbiol. & Biotech 46:(5-6) 587-592.  Antibiotics can disturb the production of biogas during anaerobic digestion. This study shows a systematic approach to understanding how the different bacterial populations involved in the final conversion of organic matter into methane are inhibited by 15 antimicrobial agents with different specificities and modes of action.  [pdf version]

Economic Assessments   (Feasibility Studies) of Anaerobic Digestion

See also: Life Cycle Assessments of Farm Energy Systems
              Anaerobic Digestion and GHG Emission Reductions

Europe

Energy and economic analysis of biogas heated livestock buildings (2003). Biomass and Bioenergy, 24(3):239-248. Petros Axaopoulos and Panos Panagakis, Agric. Eng. Dept, Agricultural U. of Athens, Iera Odos 75, 118 55, Athens, Greece  - The possibility to cover the annual space-heating requirements of a typical swine nursery by the methane produced using a solar-assisted anaerobic digester of innovative design, is studied for two Greek areas. A simple sensitivity analysis concerning the economics of the solar-assisted anaerobic digester indicated that its profitability strongly depends on to what extent the produced methane is used.

Economics of anaerobic digestion of agricultural waste: Technical summary, (Oct. 1998) [65 KB pdf]; Ian Higham, AEA Technology Environment, Culham, Abingdon, Oxfordshire (UK) OX14 3DB; Tel: +44 (0)1235 463391; Fax: +44 (0)1235 463050; environment-help1@aeat.co.uk. A comprehensive economic analysis should include any avoided costs of disposal or avoided environmental costs.  The economics of AD plant could be further improved if the environmental benefits of the plant were costed. For example the plant can contribute to reduced greenhouse gas emissions, reduced water pollution, reduced odour pollution. If economic value was placed on these benefits they could be treated as a further income stream to the plant.

Internalising Environmental Benefits of Anaerobic Digestion of Pig Slurry in Norfolk (2000) (399 KB pdf); Rachel Boyd & Julian Parfitt, U. of East Anglia (UK). The digester was most likely to be profitable if there was a developed market for the fibre. Internalising the environmental benefits resulted in the net present value (NPV) of the farm digester increasing from £13351 to £475311. If the government paid 50% grants for 60 digesters in Norfolk, the environmental benefits would give this investment a NPV of over £3.5 million, although if the savings from avoided carbon dioxide from fertiliser production were not factored in, the NPV is negative.

Anaerobic Digestion, Turning Organic Waste into Energy and Fertilizer: A pre-feasibility study of a biogas demonstration plant in the Entre o Douro e Vouga Region in Northern Portugal (Technical Summary)(Oct. 2003) [174 KB pdf]; Harold Leffertstra, U. of Zaragoza, Zaragoza, Spain - Study has assessed the economic feasibility & environmental benefits of an AD plant of 15,000 tons feedstock/year. The plant could be slightly profitable with the existing prices for electricity (70 €/MWh) and gate fees (20-30 €/ton waste) assumed investment costs of 3.5 million € and annual operation and management (O&M) cost of 250 000 €, values which are relative uncertain.

Biogas Digest (Volume III): Biogas - Costs and Benefits and Biogas – Programme Implementation [279 KB pdf] - Werner Kossmann & Uta Pönitz, Information and Advisory Service on Appropriate Technology (ISAT), Tel.: +49 6196/79-0; Fax: +49 6196/797352; E-mail: gate-isat@gtz.de ; Stefan Habermehl, Household Energy Appropriate Technologies (HEAT) GmbH - Biogas - Costs and Benefits; Macro-economic evaluation; Economic Viability (Financial Analysis).

Life Cycle Assessment of different uses of biogas from anaerobic digestion of separately collected biodegradable waste in France (Sept 2007) [104 KB pdf]. 1) to identify the best method to use the biogas from anaerobic digestion of separately collected biodegradable waste (biowaste);  2)  to evaluate the strength and weaknesses of the two main different organic recycling: anaerobic digestion (methanisation) and composting.

Socio-economic Analysis of Centralised Biogas Plants [135 KB pdf]. L.H. Nielsen & K. Hjort-Gregersen* - Risø National Lab., Frederiksborgvej 399, box 49, DK- 4000 Roskilde, Denmark;  *Danish Res. Inst. of Food Economics,  U. of South Denmark, Niels Bohrsvej 9, DK-6700 Esbjerg, Denmark.  The admixture of organic waste from industry is very important both for the corporate economy and for the socio-economic result. For the socio-economic result, admixture of organic waste contribute important combined benefits concerning e.g. increased production of biogas and energy sales, savings related to organic waste treatment, improved fertiliser value (NPK) and increased CO2 reduction.

North America - Economic Assessments
   Before 2000

The Economics of Biogas in the Hog Industry (Fall 1999) [254 KB pdf]. A Report Prepared for Natural Resources Canada (NRCan) by The Canadian Agricultural Energy End Use Data and Analysis Centre (CAEEDAC).   Climate change and the need for renewable energy have emerged as two of the most crucial issues that researchers, practitioners and corporations will have to deal with in the next millennium. These two issues have come to a head in Saskatchewan as the structure and practices of the hog industry have been experiencing significant changes. In particular, there has been a shift from small hog operations (20 to 30 sows) to larger and more intensive operations (600 to 1200 sows). Intensive livestock operations have given rise to several environmental issues concerning methane emissions and the disposal or spreading of manure. Public concerns about climate change, air pollution, water quality and rising energy consumption all place pressure on producers and industry to reduce emissions and promote pollution-free sources of energy.

Benefits, Costs and Operating Experience at Ten New Agricultural Anaerobic Digesters [See 116 KB pdf file] Mark A. Moser, Richard P. Mattocks, Dr. Stacy Gettier, Kurt Roos. Presented at: BioEnergy 98, Expanding Bioenergy Partnerships, Madison, Wisconsin, Oct. 4-8, 1998 -  Farmer motivation for building and operating anaerobic digesters has expanded from solely energy benefits to include manure treatment cost savings,nutrient conversion, odor and pathogen control, and byproduct recovery. Three dairy plug flow digesters (NY, CT, OR), three covered pig manure lagoons (NC, VA, IA) and one heated mixed pig manure digester (IL) have been placed in operation, since January 1997 with AgSTAR technical assistance.   Keeping the Neighbors Happy - Reducing Odor while Making Biogas [140 KB PDF]

Economics and Environmental Impact of Biogas Production as a Manure Management Strategy [71 KB pdf] Cady R. Engler et al, Texas A&M University. Economic analysis indicates that energy credits alone are not enough to offset the cost of investing in a biogas production facility. Credits for reductionof odors, insect pests and other environmental problems have not been included in the analysis.

Viability of Methane Production by Anaerobic Digestion on Iowa Swine Farms [43 KB pdf]. M. Ernst, J. Rodecker, E. Luvaga, T. Alexander, James Kliebenstein, John Miranowski, Dept of Agric. Economics, Iowa State U. - Speaking strictly from the standpoint of cash costs, on-farm methane production by anaerobic digestion has not attracted a huge crowd of enthusiasts due to the lack of demonstrated financial feasibility. However, potential benefits of anaerobic digestion expand beyond the cash or direct economic benefits. Anaerobic digestion offers an alternative for dealing with a number of social and economic issues, particularly those related to agriculture.

North America - Economic Assessments  
     After 2000

CANADA

How Ontario Can Profit From Green Jobs and Greenhouse Gas Reduction through Biogas. (Apr. 2009) [ KB pdf.   Ryan Little, Stormfisher Biogas.  As a result of the Green Energy Act, Ontario has the potential to emerge as a major player in the cleantech and renewable energy industries, resulting in both a healthier environment and new jobs.

Optimizing the Size of Anaerobic Digesters (2006) [208 KB pdf]. Emad Ghafoori, Peter C. Flynn, U. of Alberta. Can. Soc. for Bioeng. Paper .06-102. Anaerobic digestion of manure from confined feeding operations (CFOs) to produce biogas and in turn electric power in farm or feedlot based units as well as centralized plants is evaluated for two settings in Alberta, Canada: a mixed farming area, Red Deer County, and an area of concentrated beef cattle feedlots, Lethbridge County.

Electricity and Heat Production Using Biogas from the Anaerobic Digestion of Livestock Manure:  Literature Review (2005) [129 KB pdf]. Martin Van Haren, Ron Fleming, Ridgetown College, U. of Guelph, Ridgetown, ON, Canada N0P 2C0 - Objectives - Describe alternatives for producing electricity from biogas derived from livestock manure; Determine optimum recovery rates of energy from manure;  Determine the most appropriate generator system for typical situations;  Describe options for connection to the electrical power grid;  Determine the profitability and viability of producing electricity and heat from biogas.

Potential for hydrogen and methane production from biomass residues in Canada (2007). David B. Levin et al., Bioresource Technology, Vol. 98(3), Feb.2007, P. 654-660.  Canada generates approximately 1.45 × 10⁸ t of residual biomass per year, containing an estimated energy value of 2.28 × 10⁹ GJ, which is equivalent to about 22% of Canada’s current annual energy use. Anaerobic digestion of these biomass residues using conventional technologies could generate 1.14 × 10¹⁰ m³/year of CH₄ with a heating value of 4.56 × 10⁸ GJ. 

Agricultural Biomass Residue Inventories and Conversion Systems for Energy Production in Eastern Canada (July 2002) [751 KB pdf]. T. Helwig, R. Jannasch., R. Samson, A. DeMaio and D. Caumartin, Resource Efficient Agricultural Production (REAP) - Canada, Ste. Anne de Bellevue, Quebec, H9X-3V9 - report provides an overview of available crop residues and livestock manure in eastern Canada. The inventories are linked to an assessment of energy conversion systems that are either in the commercial stage or are in the late development or pilot stage.

A Canadian Biomass Inventory: Feedstocks for a Bio-based Economy (June 2003) [705 KB pdf]. Susan M. Wood & David B. Layzell, BIOCAP Canada Foundation, Queen’s University, Kingston, ON. A detailed analysis was carried out to assess the capacity of Canada’s biological resources – in particular, agriculture and forestry - to support a bio-based economy.

Waste-Based Energy Feasibility Study (Sept. 2003)[2591 KB pdf]. Municipality of Chatham-Kent, Ontario; prepared by: Earth Tech Canada Inc., & Kinectrics Inc., 800 Kipling Ave., Toronto, ON M8Z 6C4 (Project: 55484) - Municipality of Chatham-Kent, in consultation with representatives from the agricultural and academic sectors, determined that the feasibility of generating alternative “green” energy from the processing of an organic-based feedstock using anaerobic digestion (AD) technology should be investigated.  Ag-Impact Study [3627 KB pdf] (Ridgetown College, U. of Guelph).

Manure into Gold: A strategic framework for manure management in Ontario [344 KB pdf] (Mar. 2, 2004) Ernest Lowe, Ivan Weber, Sustainable Systems Inc., 300 Frank H. Ogawa Plaza, Suite 210, Oakland, CA. 94612- Prepared for: Centre for Research in Earth and Space Technology CRESTech), 4850 Keele St. Toronto, ON M3J 3K1; Tel: (416) 665-5413 Fax: (416) 665-2032 - This report proposes a strategic context for manure management in Ontario and focuses on priorities for short-term and long-term research and development financing. It proposes a possible mission statement that establishes a sustainable economic development context for this strategy: 

Optimum Sizing for Anaerobic Digestion (March 2006) [695 KB pdf]. Emad Ghafoori & Peter Flynn, Dept of Mechanical Eng., U. of Alberta.  The key message of this study is that small farm based manure digesters are less cost effective than centralized units that receive manure from many producers. Farmers that want to process manure and produce power are better to transport their manure than to process it on site.
See also: Optimizing the Size of Manure Anaerobic Digesters [560 KB pdf]

Economic Feasibility of Anaerobic Digesters. (2008). Alberta Agriculture & Rural Development.  factsheet provides a fairly high level, theoretical approach to exploring the costs of the technology. Data is provided in the form of tables as well as through examples that are useful to determine the economic feasibility of adopting an anaerobic digester/biogas plant for agricultural operations.

Possibilities for Anaerobic Digestion on Ontario Swine Farms (2008) [243 KB pdf]. Ron Fleming, Malcolm MacAlpine, Ridgetown College, U. of Guelph, Ridgetown, ON, Canada; project involved the use of two pilot scale anaerobic digesters at the U. of Guelph Ridgetown Campus to measure biogas production from liquid swine manure, liquid swine manure mixed with corn silage and liquid swine manure mixed with shredded sugar beets.

U.S.A.

Manure Use for Fertilizer and for Energy: Report to Congress (June 2009) [1200 KB pdf]. J.M. MacDonald, M.O. Ribaudo, M.J. Livingston, J. Beckman, and W. Huang, Econ. Res. Serv., U.S.D.A. Animal manure can be used as a fertilizer, and it can improve soil quality. Manure can also be used as a feedstock for energy production. But excessive concentrations of manure, either in storage or in land application, can create environmental risks, and farmers are facing increased regulation of their manure management practices.

Recommendations to the San Joaquin Valley Air Pollution Control Officer Regarding Best Available Control Technology for Dairies in the San Joaquin Valley (Jan., 2006) [964 KB pdf]. Dairy Permitting Advisory Group (DPAG), San Joaquin Valley Air Pollution Control District - a compilation of issues and factors that the Dairy Permitting Advisory Group (DPAG) recommends the San Joaquin Valley Air Pollution Control District consider as the District proceeds with determining the best available air pollution control technology (BACT) for future new and modifying dairy permitting applications.

Humboldt County Energy Element Background Technical Report. (2005) [pdf]. Prepared by: Schatz Energy Research Center, Humboldt State U.; Author: Jim Zoellick. California state law requires each city and county to adopt and periodically update a general plan, which serves as a local blueprint for future physical development and guides most land use decisions. The Redwood Coast Energy Authority is assisting Humboldt County's Community Services Development Department in the preparation of an “Energy Element” as part of the County’s current General Plan update process.

DeVries Dairy Bion NMS Nutrient and Atmospheric Emission Quantification Project: Analytical Approach Details and Results.  [353 KB pdf] (Oct. 2005). James Morris, Jere Northrop, George Bloom, P.E. (TEXAS).

An Evaluation Of A Mesophilic, Modified Plug Flow Anaerobic Digester For Dairy Cattle Manure. Gordondale Farms, WI) (July 2005)[372  KB pdf]. EPA/Agstar;  Eastern Research Group, Inc., 1600 Perimeter Park, Morrisville, NC 27560; John H. Martin, Jr.  - report summarizes the results from one of a series of AgSTAR studies designed to more fully characterize: 1) the air and water quality improvements provided by anaerobic digesters for managing manure and other wastes in the swine and dairy industries, and 2) the associated costs.

An Assessment of Technologies for Management and Treatment of Dairy Manure in California's San Joaquin Valley (Dec., 2005) [842 KB pdf]. Dairy Manure Technology Feasibility Assessment Panel, California Air Resources Board - There are a great many companies selling products and processes to treat manure. Although the Panel accepted submissions for only 6 weeks, we received 44 submissions, and another 25 after the deadline. It is apparent that many companies are seeing entrepreneurial opportunities for industrial scale manure management and treatment, and that these technologies hold promise for potential use as best management practices at dairies.

Biomethane from Dairy Waste: A Sourcebook for the Production and Use of Renewable Natural Gas in California (July 2005) [4761 KB pdf]. Prepared for Western United Dairymen - report examines the feasibility of producing biomethane from dairy manure. We investigated a number of possible technologies for producing renewable forms of energy and fuel from dairy wastes as well as applications and markets for these products. Although some of the applications proved to be technically or economically infeasible at this time, we believe that the information gathered could prove useful for other investigators or future studies. With this in mind, we designed this sourcebook for readers and investigators interested in exploring alternate uses of biogas created from dairy wastes.

Anaerobic Digestion Feasibility Study  (June 2004) [2900 KB pdf]. Bluestem Solid Waste Agency and Iowa Department of Natural Resources - The objectives of the study were to answer the following questions posed by Bluestem: 1. Where has AD been effectively used to manage targeted fractions of the solid waste stream?   2. Can AD be effectively used to manage the organic fraction of Bluestem's waste stream?   3. What impact would the incorporation of an AD component have on Bluestem's overall integrated solid waste management system?  4. What cost parameters are associated with the application of AD to the management of targeted fractions of Bluestem's municipal solid waste (MSW)?  5. What are the potential barriers to siting and developing an AD facility to manage a portion of Bluestem's MSW?

Environmental Impacts and Economic Comparison of Alternative Dairy Systems (Dec., 2004) [470 KB pdf]. Amanda Bilek, The Minnesota Project. Project (2000-2004) is designed to gather and distribute critical information needed by dairy producers throughout Minnesota on the environmental impacts and economic viability of various manure handling systems. A conventional dairy manure handling system, a manure handling system with an anaerobic digester (Haubenschild Farms near Princeton), and a pasture dairy will be compared.

Feasibility Study of Fuel Cells for Biogas Energy Conversion on Large Dairy Farms (Sept. 2004) [75 KB pdf]. Technical Note FC-1- Stefan Minott, Norman Scott and Brian Aldrich, Dept. of Biol. & Env. Eng., Manure Management Program, Cornell U.  Feasibility study of using fuel cells to generate heat and electricity (cogeneration) from biogas was conducted in 2002 using data from AA Dairy in Candor, NY, which has been producing biogas from the A.D. of dairy manure since 1998. Molten carbonate fuel cells (MCFC) were found to be technically feasible on dairy farms with 1,000 cows; however, MCFC systems are not expected to be economically feasible until current unit costs of about one million dollars can be significantly reduced.

An Economic Comparison of Two Anaerobic Digestion Systems on Dairy Farms (July 2003)[86 KB pdf].   Peter Wright & Scott Inglis,Biol. & Env. Engin., Cornell U.;  presented at the 2003 ASAE Ann. Int. Meet. Las Vegas, Nevada, USA - Two dairy farms in New York State have recently installed anaerobic digesters as a method to control odors and create value added by-products from their manure. The mass flow, nutrient flow and economics of these two systems will be compared.

Anaerobic Digester Methane To Energy: A Wisconsin Statewide Assessment (Jan. 2003) [478 KB pdf].  Prepared For: Focus On Energy, Thomas E. Vik,  McMahon Assoc., Inc., 1445 McMahon Dr., Neenah, WI 54956; Tel.: 920.751.4200; Fax: 920.751.4284; To determine the technical and economic feasibility of generating electricity from the methane using a packaged generation system that includes an engine, generator, gas treatment system and heat recovery system. The study would determine which size communities and treatment plants this technology makes economic and practical sense and would develop a priority list and implementation plan for those communities.

An Assessment of the Performance of the Colorado Pork, LLC. Anaerobic Digestion and Biogas Utilization System (Mar., 2003) [409 KB pdf]. John H. Martin, Jr.,  Hall Associates, 23 Evergreen Dr., Georgetown, Delaware 19947 - report summarizes the results from one of a series of studies designed to: 1) more fully characterize and quantify the protection of air and water quality provided by waste management systems currently used in the swine and dairy industries and 2) delineate associated costs; report presents an assessment of the performance of the mesophilic intermittently mixed anaerobic digester used for swine manure stabilization and biogas production at Colorado Pork, LLC. (CP), Lamar, Colorado. Also presented is an assessment of the use of the biogas captured to generate electricity.

A Comparison of Dairy Cattle Manure Management with and without Anaerobic Digestion and Biogas Utilization (Mar., 2003) [250 KB pdf]. John H. Martin, Jr., Eastern Research Group, Inc., 35 India St.,  Boston, MA 02110.. for Kurt Roos, AgSTAR Program, U.S. EPA , Ariel Rios Bldg, 200 Pennsylvania Ave. NW (6202J), Washington, DC 20460-  Objective is to develop a better understanding of: 1) the potential of individual system components and combinations of these components to ameliorate the impacts of swine and dairy cattle manures on environmental quality and 2) the relationships between design and operating parameters and the performance of the biological and physical/chemical processes involved.

Minnesota’s Potential for Electricity Production Using Manure Biogas Resources (Final Report) (April 2003) [232 KB pdf]. Minnesota Dept of Commerce, State Energy Office - basic assessment of the feasibility and potential for using animal wastes in anaerobic methane digesters to create electricity in Minnesota.

Anaerobic Digesters for King County Dairies (June, 2003)(Washington). Feasibility study: A centralized digester to serve dairies of the Enumclaw Plateau does meet feasibility requirements. It can meet the needs of all parties and produce acceptable financial returns.  Final Report [2942 KB pdf].
       Study to Evaluate the Price and Markets for Residual Solids from a Dairy Cow Manure Anaerobic Digester.(Oct. 2003). The study incorporates a review of an earlier Feasibility Study report with research into the operation of similar, existing digesters and a market study to evaluate the most likely potential market and the probable value of the solids in that market.   Full Report

Feasibility Study On Implementing Anaerobic Digestion Technology On Humboldt County Dairy Farms (CA) [324 KB pdf] (June, 2003) - Antonio Reis, Richard Engel, Schatz Energy Research Center, Humboldt State U., Arcata, CA 95521 - In summary, the dairy would have at least 400 cows that are housed in freestall barns for a portion of the year; could produce between 4 million and 6.4 million cubic feet of biogas and 124,000 to 198,000 kilowatt-hours of electricity annually, leading to potential annual avoided electrical costs of $11,100 to $23,800.

The Economics and Feasibility of Electricity Generation using Manure Digesters on Small and Mid-size Dairy Farms (Jan., 2002) [256  KB pdf]. Aashish Mehta, Dept of Agric. & Applied Economics, U. of Wisconsin, Madison WI.  This paper will serve as a first pass at the economics of digester/generators. It is hoped that the calculations and insights will be of interest to potential adopters and policy practitioners alike.

Bio-Gas Plants And Hog Farming In North Carolina [390KB pdf] (Spring, 2001). Joseph Lewis, Dept. of Economics, Duke Univ., Durham, NC. This paper proposes that in order to effectively battle environment problem economically, North Carolina adopt a system of centralized bio-gas plants that would serve numerous farms in a given area. Biogas plants used efficiently eliminate the environmental risks associated with hog farmers. A centralized biogas plant collects waste from surrounding farms and uses it to produce high quality fertilizer and energy.

Final Report for the Iowa Livestock Industry Waste Characterization and Methane Recovery Information Dissemination Project (2001) [1454 KB pdf]. M. V. Garrison & T. L. Richard, Dept of Agric. & Biosystems Eng., Iowa State U., Ames, IA 50011 - The purpose of this document is to summarize analytical methods, characterize Iowa livestock wastes, determine fossil fuel displacement by methane use, assess the market potential, and offer recommendations for the implementation of methane recovery technologies.

Centralized Digester Systems (Co-op, Community)

Bio-Gas Plants And Hog Farming In North Carolina [390KB pdf]. Joseph Lewis, Dept. of Economics, Duke Univ., Durham, NC Spring, 2001 - This paper proposes that in order to effectively battle environment problem economically, North Carolina adopt a system of centralized bio-gas plants that would serve numerous farms in a given area. Biogas plants used efficiently eliminate the environmental risks associated with hog farmers. A centralized biogas plant collects waste from surrounding farms and uses it to produce high quality fertilizer and energy. 

Danish Centralized Biogas Plants: Plant Descriptions (2000) [1295 KB pdf]. Bioenergy Dept., U. of Southern Denmark - excellent overview of 20 centralized biogas plants in Demark, including operational information on each plant.  

Danish Centralized Biogas Plants: Integrated Energy Production, Waste Treatment and Nutrient Redistribution Facilities (1999) [1982 KB pdf]. Bioenergy Dept., U. of Southern Denmark;  rationale, concepts and background to the development of Danish centralized biogas plants.

Methane Energy and Agricultural Development (MEAD) Project. (Hooley Digester). The Port of Tillamook Bay, 4000 Blimp Blvd., Tillamook, OR 97141;  tel. 503.842.2413;  installing a centralized methane digester to biologically process the manure from 4000 of the county's 30,000 dairy cows.  Manure will be picked up by facility personnel, treated, and a portion returned to participating farms. Transportation costs will be offset by sale of electricity as "green power" and by sale of fiber recovered for use by a potting soil manufacturer.

Anaerobic Digesters for King County Dairies  (June, 2003) (Washington) - feasibility study - A centralized digester to serve dairies of the Enumclaw Plateau does meet feasibility requirements. It can meet the needs of all parties and produce acceptable financial returns.  Final Report [2942 KB pdf].

“Self Screening” Assessment: “The Appropriateness of a Community Manure Food Waste Digestion System” [442 KB pdf] (Aug. 2003) Richard Mattocks,  RCM Digesters, Inc., Riverdale, NY for Agricultural Utilization Res. Inst. (AURI), Crookston, MN  - A certain minimum number of animals will be required to participate for the Community Manure Food Waste Digestion Facility to be economically viable. A rule of thumb is to have manure from the equivalent of 6000 mature Holsteins in a 5 mile driving range of the centralized facility.

Pathogen Reduction in AD systems

See also -Pathogen Issues

Factors controlling pathogen destruction during anaerobic digestion of biowastes. (2005). Waste Management 25(4)417-425. S.R. Smith et al., Dept of Civil and Environ. Eng., Imperial College London, SW7 2AZ, UK. The degree of disinfection achieved by a particular anaerobic digester is influenced by a variety of interacting operational variables and conditions, which can often deviate from the ideal. Experimental investigations demonstrate that Escherichia coli and Salmonella spp. are not damaged by mesophilic temperatures, whereas rapid inactivation occurs by thermophilic digestion.

Reduction of Selected Pathogens in Anaerobic Digestion (Oct. 2003) - P.E. Wright, (Dept of Agric. & Biol. Eng., Cornell U.) S. F. Inglis, S. M. Stehman, and J. Bonhotal  - Pap. 074-082 in the Animal, Agricultural and Food Processing Wastes, Proc. of the 9th Int. Symp., 11-14 Oct. 2003 (Raleigh, NC, USA), ed. Robert Burns. ASAE Pub #701P1203 - mesophilic systems (T=100°F) have the potential to reduce pathogens entering the environment. Results show almost a 3-log reduction in fecal coliforms and slightly more than a 2-log reduction in M. avium paratuberculosis (Map).

Pathogen Survival in Swine Manure Environments and Transmission of Human Enteric Illness—A Review. (2003) [99  KB pdf]. Tat Yee Guan, Richard A. Holley.Dept of Food Science, U. of Manitoba, Winnipeg, MB, R3T 2N2; J. Env. Qual. 32:383–392; Generally, pathogens survived longer in environmental samples at cool temperatures but differences were seen in liquid and solid manure. Based on actual data plus some data extrapolated from cattle manure environments, holding manure at 25°C for 90 d will render it free from the pathogens considered (Escherichia coli O157:H7, Salmonella, Campylobacter, Yersinia, Cryptosporidium,and Giardia)  (reference publication).

Evaluation of the pathogen reduction from plug flow and continuous feed anaerobic digesters. [69 KB pdf]. J. H. Harrison et al.,  WSU-Puyallup, 7612 Pioneer Way, Puyallup, WA 98371. Samples of pre-AD liquid, post AD liquid, and post AD solid were assayed bi-weekly, on two consecutive days, for six sampling events from a continuous feed and plug flow AD. Samples were quantitatively assayed for generic E-coli and enterococci and qualitatively assayed for Mycobacterium avium paratuberculosis (MAP), and bovine enterovirus, and Salmonella spp. While substantial quantitative reductions occurred for E. coli and enterococci, the low level of survival of these indicator organisms along with the frequent survival of enterovirus and MAP indicates that anaerobic digestion, even followed by composting, would not remove all biosecurity hazard.

Reduction Of Selected Pathogens In Anaerobic Digestion [ KB pdf]. P. E. Wright et al., Cornell Univ. Results show almost a 3-log reduction in fecal coliforms and slightly more than a 2-log reduction in Map. This paper describes an anaerobic digester and shows the comparative results of testing between a farm with a digester and a farm without a digester.

Inactivation of virus during anaerobic digestion of manure in laboratory scale biogas reactors. (1996). Antonie van Leeuwenhoek Vol 69(1):25-31. Reduction of porcine parvovirus, bovine enterovirus and faecal enterococci were measured in biogas reactors continuously run on manure and manure supplemented with household waste at 35°C and 55°C and in batch test run at 70°C. The death rates for faecal enterococci were generally higher than for porcine parvovirus and lower than for bovine enterovirus.

Bruce T. Bowman, Archivist
Last Updated: Thursday, May 03, 2012 03:50:02 PM