Digester Performance Evaluations
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
Prior to the development of the protocol for assessing digester performance, AgSTAR commissioned a series of studies to characterize the environmental and financial improvements provided by anaerobic digestion systems, which are provided below:
Comparison of the Performance of a Conventional and a Modified Plug Flow Digester for Scraped Dairy Manure (PDF) (8 pp, 127K) Jack Martin, Hall Associates, presented this paper at the American Society of Agriculture and Biological Engineer's International Symposium on Air Quality and Waste Management for Agriculture, September 16, 2007. Co-authored with Kurt Roos, AgSTAR, this paper presents a comparison of the performance of a conventional and a modified plug flow digester for scraped dairy cattle manure based on results from 12-month studies to characterize the performance of each design with respect to waste stabilization and biogas production and utilization.
A Comparison of the Performance of Three Swine Waste Stabilization Systems (PDF) (26 pp, 64K) This report presents a comparison of the efficacy of three stabilization systems in reducing the air and water pollution potential of swine wastes based on materials balances developed from results of analyses of samples collected over a 12-month period. The three systems are: a covered anaerobic lagoon followed by an effluent storage pond previously used as a combined treatment and storage lagoon for a farrow-to-wean operation; a minimally aerated single-cell lagoon with ozone injection; and a single-cell anaerobic lagoon for finishing operations.
An Assessment of the Performance of the Colorado Pork, LLC. Anaerobic Digestion and Biogas Utilization System (PDF) (43 pp, 412K) This report analyses the performance and associated costs of an in-ground, heated and mixed digester at a farrow-to-wean swine operation in Colorado.
A Characterization of Transformations Occurring As Swine Manure Accumulates in Deep Pits (PDF) (32 pp, 282K) This report analyses the physical and chemical transformations that occur as swine manure accumulates in deep pits under a slatted floor and uses this information to assess emissions of methane, ammonia, and hydrogen sulfide; and manure characteristics that potentially affect water quality.
An Evaluation of a Covered Anaerobic Lagoon for Flushed Dairy Cattle Manure Stabilization and Biogas Production (PDF) (46 pp, 140K) This report analyses the performance and associated costs of a manure management system operating on a flush dairy in California. The study's focus was the performance of an unheated, covered anaerobic lagoon in a subtropical climate with biogas utilization to produce electricity.
A Comparison of Dairy Cattle Manure Management with and without Anaerobic Digestion and Biogas Utilization (PDF) (59 pp, 543K) This report compares the performance and associated costs of two dairy manure management strategies at two typical upstate New York dairy farms. One of these farms uses a storage pond and the other uses a plug flow digester with biogas utilization to produce electricity.
Evaluation of Mesophilic, Modified Plug Flow Anaerobic Digester for Dairy Cattle Manure (PDF) (38 pp, 372K) This report analyses the performance of a manure management system operating on a dairy in Wisconsin. The study's focus was the performance of a modified plug flow anaerobic digester for dairy cattle manure in a cold climate, as well as the performance of a screw press separator for the recovery of coarse solids.