Frear

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 […]

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 […]

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 […]

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 […]

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; […]