Anaerobic Digestion (Biogas)
Anaerobic digestion (AD) is a process in which organic matter from wet organic wastes (i.e. liquid manure, food processing wastes, etc.) is converted into methane by bacteria in the absence of oxygen. The methane is then collected and may be used to generate combined heat and power (CHP) or renewable methane fuel (RNG). In addition, the AD process creates potentially valuable by-products (i.e. fibrous solids/peat moss replacement and liquid wastewater rich in bio-available nutrients) while also alleviating key environmental concerns. These include reduction in odor, indicator pathogens, and greenhouse gas emissions as compared to non-AD baselines.
CSANR views AD as important technology for organic management but more importantly as a core unit operation in a grander vision of a bio-refinery. Within the bio-refinery approach multiple wastestreams are collected, separated and selectively treated for more efficient processing while also harnessing interconnected synergies and production of multiple co-products and revenue streams. CSANR has supported extensive efforts in improving AD technology for:
- multiple organic wastes,
- co-digestion of manure with outside organics,
- development and demonstration of novel nutrient recovery technologies for production of concentrated nutrient co-products,
- development and demonstration of novel biogas purification systems,
- integration of pyrolysis/chars within an AD platform,
- reporting of reliable techno-economic and feasibility studies related to farm-based AD projects, and
- technical/extension/outreach support for farmers, rural communities, project developers, and engaged agencies.
See also our Small-Scale Biogas page.
Featured Anaerobic Digestion Publications
Astill, G., R. Shumway, and C. Frear. 2016. This tool calculates the economic value of investment under a variety of technology and price scenarios for an AD system. The budget calculator includes options for anaerobic digestion, codigestion, compressed natural gas, combined heat and power, environmental credits, fiber solids separation, phosphorous solids separation, struvite precipitation, ammonium sulfate recovery, and water ultra-filtration/reverse osmosis.
Astill, G.M. and C.R. Shumway. Washington State University, School of Economic Sciences Working Paper 2016-5, March 2016.
Astill, G.M. and C.R. Shumway. Washington State University, School of Economic Sciences Working Paper 2016-2, March 2016.
Astill, G.M. and C.R. Shumway. Washington State University, School of Economic Sciences Working Paper 2016-1, February 2016.
N. Kennedy, G. Yorgey, C. Frear, D. Evans, J. Jensen, C. Kruger. 2015. WSU Fact Sheet FS180E. This fact sheet is to provide farmers, third party project developers, regulatory agencies, and other stakeholders with a basic understanding of the chemical composition of renewable natural gas, the most appropriate end-use options for dairy digesters, and some of the more common techniques used to clean biogas to RNG quality at dairy digesters. In describing specific technologies, the authors aim to provide information based on the current literature, but not to favor one technology over another. For additional detail or information about other technologies, more comprehensive reports and reviews are available (Krich et al. 2005; Ryckebosch et al. 2011; Jensen 2011).
N. Kennedy, G. Yorgey, C. Frear, C. Kruger 2015. WSU Fact Sheet FS172E. Anaerobic Digestion Systems Series provides research-based information to improve decision-making for incorporating, augmenting, and maintaining anaerobic digestion systems for manures and food by-products. This publication focuses on pre-consumer food wastes that can sustainably be used as substrates for co-digestion with dairy manure and increase the value of co-products. Topics covered include complementary and problematic substrates, the substrate procurement process, regulations, and solutions for co-digestion processing issues.
S. M. Mitchell, N. Kennedy, J. Ma, G. Yorgey, C. Kruger, J. L. Ullman, C. Frear. Sept 2015. WSU Fact Sheet FS171E. Anaerobic digesters are used worldwide to produce bioenergy and sustainably treat organic waste from municipal, industrial, and agricultural operations. This fact sheet reviews the basic elements of anaerobic digestion and the process used by digesters, including the types of digesters, biochemistry of influents and effluents, laboratory evaluations and optimizing anaerobic digesting through modeling.
Galinato, S., C. Kruger, and C. Frear. 2015. WSU Extension Publication EM090E. This publication introduces readers to key concerns regarding the profitability of anaerobic digestion systems and includes a discussion of general project costs and potential revenue sources. This publication also examines the potential profitability of three alternative anaerobic digester systems: (a) combined heat and power, which is the baseline system; (b) boiler as a substitute for combined heat and power; and (c) renewable natural gas infrastructure.
Yorgey, G., C. Frear, C. Kruger, T. Zimmerman. 2014. WSU Extension Fact Sheet FS136E.
Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.
Kennedy, N. 2013. BioCycle Magazine. Feasibility study supports a shift from the conventional CHP model to a renewable natural gas (RNG) model that takes advantage of the accelerating move to natural gas fuels in the transportation sector.
Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.
Prepared for Innovation Center for US Dairy by Jingwei Ma, Nick Kennedy, Georgine Yorgey and Craig Frear. Nov 2013. Washington State University.
Mitchell, S., J. Ullman, A. Teel, R. Watts, C. Frear. Bioresource Technology Volume 149, December 2013, Pages 244–252.
Website highlighting a WSU – Bellingham Technical College partnership to offer training for anaerobic digestion technicians. Full curriculum, videos and more available online.
Jarvis, E. R. Davis, C. Frear. Aug 2013.
C. Frear, C.Kruger, H. Collins, M. Garcia-Perez, C. Stockle, R. Shumway, G. Astill, T. Ewing, N. Kennedy, T. Khalil, and G. Yorgey. July 2013. Academic Poster.
Frear, C, M. Garcia-Perez, C. Kruger, S. Chen. 2013.
J. Ma, B. Zhao, C. Frear, Q. Zhao, L. Yu, X. Li, S. Chen. June 2013.Bioresource Technology Volume 137, June 2013, Pages 41–50.
May 2013. CSANR produced a 7.5 minute video showing how state-of-the-art anaerobic digestion systems can offer multiple benefits to society.
April 2013. Zhao, B., J. Ma, Q. Zhao, and C. Frear. WSU subcontract work on Department of Energy Project 22902.
J. Ma, C. Frear, Z. Wang, L. Yu, Q. Zhao, X. Li, S. Chen. Bioresource Technology. Volume 134, April 2013, Pages 391–395.
J. Ma, L. Yu, C. Frear, Q. Zhao, X. Li, S. Chen. Bioresource Technology. Volume 131, March 2013, Pages 6–12.
May 2012. Coppedge, B., G. Coppedge, D. Evans, J. Jensen, K. Scanlan, B. Scanlan, P. Weisberg, and C. Frear. An anaerobic digester case study for alternative outtake markets. A report to Washington State Department of Commerce.
WSU and Bellingham Technical College produced this video as a part of their grant-funded Anaerobic Digestion Technician certificate program. The video explains the technical aspects of operating and maintaining an anaerobic digester.
Frear, C., Ewing, T., Yu, L., Ma, J., and Chen, S. 2012. Olympia, WA. Washington State Department of Ecology.
Q. Zhao, A. Jiang, L. Yu, C. Frear, and S. Chen. Poster presented June 2011.
Western Rural Development Center’s Rural Connections Newsletter Climate Change issue June 2011 contains three articles written by CSANR faculty and staff members. View the entire issue here (6 MB), or view the individual articles by clicking the titles here: Anaerobic Digestion in the Pacific Northwest; Climate Change and Family Forest Landowners in the Pacific Northwest: Attitudes & Understanding; Climate Change and Agriculture in the Pacific Northwest.
With support from USDA Western Sustainable Agriculture Research & Education Program (Western SARE), CSANR developed a project to explore options for developing improved technology for applications in small farm settings in the US. Resources developed in the project are available on this site.
Professor Shulin Chen’s Research Laboratory group at the WSU Department of Biological Systems Engineering. Research efforts include organic waste inventory and characterization; anaerobic digestion of manure and food processing wastes; High Solids Anaerobic Digestion for the Organic Fraction of Municipal Solid Wastes (OFMSW); recovery of nutrients and fertilizers from organic wastes; and pre-treatment technology for advanced biofuels derived from organic wastes.
Additional Anaerobic Digestion Publications
L. Yu, Q. Zhao, J. Ma, C. Frear, S. Chen. Bioresource Technology. Volume 124, November 2012, Pages 8–17.
May 2012. Coppedge, B., G. Coppedge, D. Evans, J. Jensen, K. Scanlan, B. Scanlan, P. Weisberg and C. Frear. An anaerobic digester case study for alternative outtake markets and remediation of nutrient loading concerns within the region. A report to Washington State Department of Commerce.
This webinar highlights recent research by Rita Hummel of WSU on struvite as a phosphorus source for greenhouse production of bedding plants and vegetable starts. Her research includes struvite derived from municipal wastewater and dairy manure. Craig Cogger opened the webinar with a brief overview of the phosphorus challenge. After Rita’s presentation of greenhouse research results, Keith Bowers discussed struvite production as one phosphorus removal technology for wastewater at livestock, food processing, and public sewage treatment sites. The webinar closed with a brief summary by Craig and an open question period.
Streubel, J. D., H. P. Collins, J. M. Tarara, and R. L. Cochran.; Posted online 5 Jan. 2012
WSU scientists have conducted extensive research on Anaerobic Digestion (AD) as a technology for recovery of methane (energy), stable carbon, and nutrients from organic wastes such as manure, food processing wastes and the organic fraction of municipal solid wastes (OFMSW). Our research has evaluated the technical and economic performance of commercially available systems, developed improved AD reactors, and commercialized WSU patented nutrient recovery technology. This webinar, presented by CSANR director Chad Kruger and CSANR scientist Craig Frear, will provide an update on the latest results from the WSU Climate Friendly Farming Project’s AD research.
Frear, C., W. Liao, T. Ewing, and S. Chen. Clean – Soil, Air, Water 2011,39 (7), 697–704.
WSU Extension Fact Sheet FS040E. Yorgey, G., C. Kruger, K. Steward, C. Frear, & N. Mena. August 2011.
Frear, C., Wang, Z., Li, C., Chen, S., (2011). Journal of Chemical Technology & Biotechnology, 86:145-152.
C. Frear. May 2011. PowerPoint presentation at 2011 AgSTAR Conference.
Z. Wang, J. Ma, S. Chen. Bioresource Technology. Volume 102, Issue 2, January 2011, Pages 697–702.
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