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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 Publications

Nutrient Recovery: Products from dairy manure to improve soil fertility

Benedict, C., J. Harrison, S. Hall, G. Yorgey. 2018. Washington State University. FS305E.

Approaches to Nutrient Recovery from Dairy Manure

Frear, C., J. Ma, G. Yorgey. 2018. WSU Fact Sheet EM112E. This fact sheet is part of the AD Systems Series.

Completing a Successful Feasibility Study for an Anaerobic Digestion Project

Jensen, J., C. Frear, C. Kruger, G. Yorgey. Jan. 2018. WSU Fact Sheet FS292E. This fact sheet is part of the AD Systems Series.

Technology Research and Extension Related to Anaerobic Digestion of Dairy Manure, 2015-2017 Biennium

Garcia-Pérez, M., Chen, S., Kruger, C., Yorgey, G., Ai, P., Ayania, M., Dunsmoor, A., Englund, K., Ewing, T., Frear, C., Gao, A., Ghoghare, R., Hall, S.A., Jensen, J., Ma, J., Manoharan, G., Martinez, J., Nasir, A., Parlina, I., Pelaez-Samaniego, M.R., Pereira-Ferraz, G., Rajagopalan, K., Smith, M., Suliman, W., Wang, D., Yao, Y., Yu, L. 2017. Compiled and edited by Hills, K., Hall, S.A., Saari, B., Zimmerman, T. A Project Report for the Washington State University Agricultural Research Center and the Washington State Department of Agriculture. 173 pp.

Video: Recovering Nutrients from Manure – New Tools for Maintaining Air and Water Quality

Hall, S., and G.G. Yorgey. 2017.  Produced by CAHNRS Communications. Washington State University, Pullman, WA.  This video profiles two Washington State dairies – Edaleen Dairy and Royal Dairy – who have implemented new technologies that partition, and in some cases recover, some of the nitrogen and phosphorus in manure. The video discusses both the potential that these new tools have to improve manure management for dairies, and some of the challenges that remain.

Soil Amendments

Yorgey, G., W. Pan, R. Awale, S. Machado, A. Bary. 2017. Chapter 7 In Yorgey, G. and C. Kruger, eds. Advances in Dryland Production Systems in the Pacific Northwest. Washington State University Extension, Pullman, WA.

Approaches for adding value to anaerobically digested dairy fiber

Manuel Raul Pelaez-Samaniego, Rita L Hummel, Wei Liao, Jingwei Ma, Jim Jensen, Chad Kruger, and Craig Frear. 2017. Renewable and Sustainable Energy Reviews 72, 254-268.

Digested Fiber Solids: Methods for Adding Value

Jim Jensen , Dr. Craig Frear , Dr. Jingwei Ma , Chad Kruger , Rita L. Hummel , Georgine Yorgey , WSU Fact Sheet FS235E. November 2016.  This publication describes the composition and separation process for fibrous solids that result from the digestion of dairy manures. It also reviews both current and future potential uses of fiber. This fact sheet is part of the AD Systems Series.

Profits from pollutants: Economic feasibility of integrated anaerobic digester and nutrient management systems

Astill, G.M. and C.R. Shumway.  Journal of Environmental Management. 2016. In Press.

Phosphorus Uptake by Potato from Fertilizers Recovered from Anaerobic Digestion

Collins, H. P., E. Kimura, C. S. Frear, and C. E. Kruger. 2016. Agron. J. 108:2036-2049. doi:10.2134/agronj2015.0302

Economic Feasibility of Anaerobic Digester Systems with Nutrient Recovery Technologies

Galinato, S. P., C. E. Kruger, and C. Frear. Sept. 2016. WSU Fact Sheet TB27E. This publication analyzes the economic feasibility of three nutrient recovery technologies that work in tandem with anaerobic digester systems. This fact sheet is part of the AD Systems Series.

Assessing the effect of different treatments on decomposition rate of dairy manure

Khalil, Tariq M. , Stewart S. Higgins, Pius M. Ndegwa, Craig S. Frear, Claudio O. Stöckle.  Journal of Environmental Management, Volume 182, 1 November 2016, Pages 230-237, ISSN 0301-479.

Considerations for Incorporating Co-Digestion on Dairy Farms

Kennedy, N., G. Yorgey, C. Frear, and C.E. Kruger. July 2016. WSU Fact Sheet EM088E. This publication discusses the impacts of incorporating co-digestion at dairy-based anaerobic digesters. That is, mixing manure with non-manure waste in anaerobic digesters. This information is based on stakeholder perspectives and a literature review of infrastructure, operational upgrades, and related costs and revenues when non-manure wastes are added to dairy digesters. This fact sheet is part of the AD Systems Series.

Anaerobic digestion effluents and processes: the basics

S. M. Mitchell, N. Kennedy, J. Ma, G. Yorgey, C. Kruger,  J. L. Ullman, C. Frear.  Sept 2015. WSU Fact Sheet FS171E. 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. This fact sheet is part of the AD Systems Series.

On-Farm Co-Digestion of Dairy Manure with High-Energy Organics

N. Kennedy, G. Yorgey, C. Frear, C. Kruger 2015. WSU Fact Sheet FS172E. 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. This fact sheet is part of the AD Systems Series.

Biogas Upgrading on Dairy Digesters

N. Kennedy, G. Yorgey, C. Frear, D. Evans, J. Jensen, C. Kruger. 2015. WSU Fact Sheet FS180E.  This fact discusses 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. This fact sheet is part of the AD Systems Series.

Anaerobic Digester Project and System Modifications: An Economic Analysis

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 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. This fact sheet is part of the AD Systems Series.

Technology Research and Extension Related to Anaerobic Digestion of Dairy Manure, 2013-2015 biennium

Chen, S., C. Frear, M. Garcia-Perez, C. Kruger, A. Abghari, P. Ai, N. Abu-Lail, G. Astill, I. Dallmeyer, M. Flury, A. Fortuna, A. Gao, J. Garcia-Nunez, R. Ghoghare, J.B. Harsh, H. Iqbal, J. Jensen, N Kennedy, J. Ma, S. Mitchell, M. Smith, W. Suliman, D. Wang, G. Yorgey, L. Yu, Q. Zhao, S. Zhang, and T. Zhu. 2015. Washington State Department of Agriculture, Olympia, WA.

Advancing Organics Management in Washington State: The Waste to Fuels Technology Partnership

Chen, S., C. Frear, M. Garcia-Perez, J. Jensen, D. Sjoding, C. Kruger, N. Abu-Lail, G. Astill, I. Dallmeyer, M. Flury, A. Fortuna, J. Garcia-Nunez, S. Hall, J.B. Harsh, H. Iqbal, N Kennedy, J. Ma, S. Mitchell, B. Pecha, R. Pelaez-Samaniego, A. Seker, M. Smith, W. Suliman, G. Yorgey, L. Yu, and Q. Zhao. 2016. Publication 16-07-008. Washington Department of Ecology, Olympia, WA.

Evaluation of an integrated ammonia stripping, recovery, and biogas scrubbing system for use with anaerobically digested dairy manure

Jiang, A., Zhang, T., Zhao, Q., Chen, S., Li, X., Frear, C. (2014). Biosystems Engineering, 119: 117-126.

The selective removal of H2S over CO2 from biogas in a bubble column using pretreated digester effluent

Kennedy, N., Zhao, Q., Ma, J., Chen, S., and Frear, C. (2015). Separation and Purification Technology 144, 240-247.

Anaerobic digestion of C1-C4 light oxygenated organic compounds derived from the torrefaction of lignocellulosic materials

Liaw, S.S., Frear, C., Lei, W., Zhang, S., Garcia-Perez, M. (2015). Fuel Processing Technology, 131: 150-158.

Ammonia recovery from anaerobic digester effluent through direct aeration

Zhao, Q., Ma, J., Zeb, I., Yu, L., Chen, S., Zheng, Y.M., and Frear, C. (2015). Chemical Engineering Journal 279, 31-37.

Anaerobic Digester System Enterprise Budget Calculator

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.

The Market Impact of Widespread Adoption of Anaerobic Digestion with Nutrient Recovery Technology in US Dairy Industry

Astill, G.M. and C.R. Shumway. Washington State University, School of Economic Sciences Working Paper 2016-2, March 2016.

A Real Options Analysis with Learning Spillovers: Investment in Anaerobic Digester Technology

Astill, G.M. and C.R. Shumway. Washington State University, School of Economic Sciences Working Paper 2016-1, February 2016.

The Dairy Manure Biorefinery

Graphic poster depicting the biorefinery concept. Developed by Nick Kennedy, Jingwei Ma, Craig Frear, Georgine Yorgey, Tara Zimmerman, Chad Kruger, and Jim Jensen.

The Rationale for Recovery of Phosphorus and Nitrogen from Dairy Manure

Yorgey, G., C. Frear, C. Kruger, T. Zimmerman. 2014. WSU Extension Fact Sheet FS136E. This fact sheet is part of the AD Systems Series.

Additional Publications

Dairy Waste Biorefinery

Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.

Economics of Dairy Digesters in Washington State

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.

Organic Waste Biorefinery

Kennedy, N., C. Frear, M. Garcia-Perez, C. Kruger, and S. Chen. 2013. Concept illustration and description.

Review of emerging nutrient recovery technologies for farm-based anaerobic digesters and other renewable energy systems

Prepared for Innovation Center for US Dairy by Jingwei Ma, Nick Kennedy, Georgine Yorgey and Craig Frear.  Nov 2013.  Washington State University.

The effects of the antibiotics ampicillin, florfenicol, sulfamethazine, and tylosin on biogas production and their degradation efficiency during anaerobic digestion

Mitchell, S., J. Ullman, A. Teel, R. Watts, C. Frear.  Bioresource Technology Volume 149, December 2013, Pages 244–252.

Anaerobic Digestion (AD) Technology Certificate Program

Website highlighting a WSU – Bellingham Technical College partnership to offer training for anaerobic digestion technicians.  Full curriculum, videos and more available online.

Efficient Use of Algal Biomass Residues for Biopower Production with Nutrient Recycle: Final Project Report

Jarvis, E. R. Davis, C. Frear. Aug 2013.

Anaerobic Digestion Systems: Integrating emerging technologies to improve environmental and economic impact

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.

2011-2013 Anaerobic Digestion Related R&D Research Summary for WSU ARC/WSDA Appendix-A Funds

Frear, C, M. Garcia-Perez, C. Kruger, S. Chen. 2013.

Methanosarcina domination in anaerobic sequencing batch reactor at short hydraulic retention time

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.

External Links

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