Methane Production via Anaerobic Digestion of Feedlot Manure

A.K. Watson, G.E. Erickson, S.C. Fernando, T.J. Klopfenstein, A.Schmidt

Trial 1Seven, 1 L anaerobic digestersCattle Diets: Control WDGS

82.5% DRC47.5% DRC5% Molasses 40% WDGS7.5% Alfalfa 7.5% Alfalfa5% Supplement 5% Supplement 0.986% Urea

Trial 2Cattle Housing: Open Lot Confinement Manure OM 26% 88%

Trial 3Ten, 45 L anaerobic digestersCattle Housing: “Pure” manure 80% OM Soil surface of pen 10% OM Stockpiled 20% OM Fresh 25% OM Cement pad 50% OM

Trial 1: Effects of cattle diet Trial 2: Effects of cattle housing

CONT WDGS SEM P-value CONF FDLT SEM P-value

DMD, % 42.7 44.9 1.06 0.05 39.0 19.9 2.79 < 0.01

OMD, % 51.0 52.9 1.14 0.10 46.7 24.8 3.11 < 0.01

Methane, L/d 0.551 0.634 0.05 0.10 0.478 0.229 0.07 < 0.01

Methane, L/g OM fed 0.116 0.137 0.01 0.05 0.103 0.189 0.03 0.01

Trial 1: Effects of cattle diet on microbial communityEubacteria Archaea

CONT

WDGS177 137

8747

-0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5

-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5Principal Coordinate Analysis

Bacteria-WDGS Bacteria-CONTArchaea-WDGS Archaea-CONT

PC1 (23.6% - Bacteria, 53.9% - Archaea)

PC2

(15.

5% -

Bact

eria

, 14.

0% -

Arch

aea)

ConclusionsTrial 1• Manure from cattle fed WDGS had increased methane potential compared to corn

based CONT• Dietary changes can lead to changes in microbial community that provide

opportunities to alter methane production from cattle manureTrial 2• Open lot manure can be used as anaerobic digester feedstock if ash buildup is avoidedTrial 3—In progress• Strategically harvesting manure may enhance methane production from open lot

manure and allow the feedlot industry to implement anaerobic digestion of manure

Cement Pad

Soil surface

Introduction Results

Variation in Microbial CommunityHomova Archaea P < 0.001 Eubacteria P = 0.019Amova Archaea P < 0.001 Eubacteria P < 0.001