Frear Publications

74 Publications

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.

Anaerobic Digestion: Beyond Waste Management

May 2013. CSANR produced a 7.5 minute video showing how state-of-the-art anaerobic digestion systems can offer multiple benefits to society.

Anaerobic Digestion of Algal Biomass Residues with Nutrient Recycle

April 2013. Zhao, B., J. Ma, Q. Zhao, and C. Frear.  WSU subcontract work on Department of Energy Project 22902.

A simple methodology for rate-limiting step determination for anaerobic digestion of complex substrates and effect of microbial community ratio

J. Ma, C. Frear, Z. Wang, L. Yu, Q. Zhao, X. Li, S. Chen. Bioresource Technology.  Volume 134, April 2013, Pages 391–395.

Kinetics of psychrophilic anaerobic sequencing batch reactor treating flushed dairy manure

J. Ma, L. Yu, C. Frear, Q. Zhao, X. Li, S. Chen. Bioresource Technology.  Volume 131, March 2013, Pages 6–12.

Experimental and modeling study of a two-stage pilot scale high solid anaerobic digester system

L. Yu, Q. Zhao, J. Ma, C. Frear, S. Chen. Bioresource Technology. Volume 124, November 2012, Pages 8–17.

Renewable Natural Gas Feasibility for Qualco Energy

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.

Renewable Natural Gas and Nutrient Recovery Feasibility for DeRuyter Dairy

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.

Anaerobic Digester Technician video – Bellingham Technical College

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.

Two novel floor-scale anaerobic digester systems for processing food waste. Part 1: Multi-reactor, liquid recycle system for high solids. Part 2: Moderate solids system.

Frear, C., Ewing, T., Yu, L., Ma, J., and Chen, S. 2012. Olympia, WA. Washington State Department of Ecology.

Estimating greenhouse gas emissions from soil following liquid manure applications using a unit response curve method

G. Wang, S. Chen, C. Frear. Geoderma. Volume 170, 15 January 2012, Pages 295–304.

Extracting valuable energy, carbon and nutrient resources from organic waste

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.

Evaluation of Co-Digestion at a Commercial Dairy Anaerobic Digester

Frear, C., W. Liao, T. Ewing, and S. Chen. Clean – Soil, Air, Water 2011,39 (7), 697–704.

Anaerobic Co-Digestion on Dairies in Washington State – The solid waste handling permit exemption

WSU Extension Fact Sheet FS040E. Yorgey, G., C. Kruger, K. Steward, C. Frear, & N. Mena. August 2011. This fact sheet is part of the AD Systems Series.

Biogas potential and microbial population distributions in flushed dairy manure and implications on anaerobic digestion technology

Frear, C., Wang, Z., Li, C., Chen, S., (2011). Journal of Chemical Technology & Biotechnology, 86:145-152.

An Integrated Pathogen Control, Ammonia and Phosphorus Recovery System for Manure and/or Organic Wastes

Q. Zhao, A. Jiang, L. Yu, C. Frear, and S. Chen. Poster presented June 2011.

WRDC Rural Connections Newsletter: Climate Change issue

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.

An Integrated Pathogen Control, Ammonia and Phosphorus Recovery System for Manure and/or Organic Wastes

C. Frear. May 2011. PowerPoint presentation at 2011 AgSTAR Conference.

Smale-Scale Biogas Plant Enterprise Assessment Tool

A worksheet to facilitate preliminary planning for a biogas plant on a small farm.

Biofuel Economics and Policy for Washington State

This report is a comprehensive response to 2007 Washington State legislation (HB 1303) that tasked Washington State University to 1) analyze the types and corresponding amounts of biofuel in the state and 2) recommend viable incentive programs to promote biofuel market development. Inside you will find policy recommendations based on analysis of a broad set of policy options, including renewable fuel standards and subsidies, carbon taxes, as well as approaches to support research, implementation of new technologies, and creation of infrastructure.

Leaching Bed Reactor for Producing Stabilized Plant Growing Media from Dairy Manure

Liao, W., Frear, C., Oakley, K., Chen, S. (2010). Biosystems Engineering 106(3), 278-285.

Bioenergy as an Agricultural GHG Mitigation Strategy in Washington State

Chapter 22 in Climate Friendly Farming: Improving the Carbon Footprint of Agriculture in the Pacific Northwest. Full report available at

« Older Frear Publications

Newer Frear Publications »