Kennedy Publications

13 Publications

Biogas Upgrading on Dairy Digesters

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).

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

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.

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. 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.

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.

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.

Monitoring Soil Carbon Pools and Fluxes Following Land Conversion to Irrigated Agriculture in a Semi-arid Shrub Steppe Ecosystem

Chapter 19 in Climate Friendly Farming: Improving the Carbon Footprint of Agriculture in the Pacific Northwest. Full report available at

Soil carbon pools and fluxes following land conversion in a semi-arid shrub-steppe ecosystem

Cochran, R.L., H.P. Collins, A.C. Kennedy, and D.F. Bezdicek. 2007. Biology and Fertility of Soils. 43:479-489.

Effects of Biodynamic Preparations on Compost Development.

Carpenter-Boggs, L., J. Reganold, A. Kennedy. 2000. Biol. Agric. Hortic. 17:313-328. The study showed that additions of herbal biodynamic preparations to compost piles resulted in consistently higher pile temperature during active composting, and higher nitrate levels and lower dehydrogenase:carbon dioxide release in mature compost samples, compared to the control.

Organic and Biodynamic Management: Effects on Soil Biology

Carpenter-Boggs, L., A.C. Kennedy, J.P. Reganold. 2000. Soil Sci. Soc. Am. J. 64:1651-1659.

Use of phospholipid fatty acids and carbon source utilization patterns to track microbial community succession in developing compost.

Carpenter-Boggs, L., A.C. Kennedy, J.P. Reganold. 1998. Applied and Environmental Microbiology 64:4062-4064.