demonstration of biogas production using low moisture content

Conclusions
CONCLUSIONS AND SUGGESTIONS FOR FURTHER ACTIVITIES
Beef cattle feedlots in the Texas panhandle produce more than 6 million beef cattle annually, and the manure
from these feedlots represents a tremendous biogas energy potential. This project utilized laboratory and field
experiments to evaluate biogas production from beef cattle manure scraped from open lots. The field project
evaluated using landfill-type cells for producing biogas from beef cattle manure. In laboratory experiments
where low density polyethylene (LDPE) containers were used as mini digesters, we discovered that the
containers were too permeable to gases to obtain representative biogas production rates. In modified
experiments, biogas production rates reached a maximum of 0.14 liters per gram VS at a wet basis moisture
contents of 70%, which is lower than published values of about 0.3 liters per gram VS.
In the field demonstration project, biogas was produced during a 12 week period in August through October. A
total of 1,500 m 3 of biogas was produced at a rate of 0.10 liters per gram VS. While the results are promising,
only producing biogas for 3 months out of the year severely limits the application of this method at beef cattle
feedyards. A heated digester would produce biogas year-round, however, additional studies and engineering
work are warranted to see if the landfill-cell method would be economically justifiable for use at beef cattle
feedyards.
REFERENCES
Angelidaki, I. and B.K. Ahring. 1994 Anaerobic thermophilic digestion of manure at different ammonia leads:
Effect of temperature. Water Research 28: 727-731.
ASAE, 1999. Uniform terminology for rural waste management. ASAE Standard S292.5. American Society of
Agricultural Engineers, St. Joseph, MI.
Engler, Cady R. and Marshall J. McFarland. 1997. Dairy manure digestion research and demonstration project.
In Proceedings of Workshop #1, Livestock Waste Streams: Energy and Environment. pp. 64-68. Texas
Renewable Energy Industries Association:Austin, TX.
Hansen, Kaare Hvid, Irini Angelidaki and Birgitte Kiger Ahring. 1998. Anaerobic digestion of swine manures:
inhibition by ammonia. Water Research 32:5-12.
Kottwitz, D.A. and D.D. Schulte. 1982. Tumble-mix anaerobic digestion of dry beef manure. ASAE Paper
Presented at the 1982 Winter Meeting, American Society of Agricultural Engineers, St. Joseph, MI.
Misra, Upama, Sonjay Singh, Amarika Singh, and G.N. Pandey. 1992. A new temperature controlled digester
for anaerobic digestion for biogas production. Energy Conservation Management 33:983-986.
Nalgene, 1999. Physical properties of Nalgene Labware, Internet Source.
Parker, D.B., B.W. Auvermann, B.A. Stewart and C.A. Robinson. 1997. Agricultural energy consumption,
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