Manure Processing: Microbial Impacts on Manure

Management Strategies

July 13, 2016

Becky Larson Assistant Professor and Extension Specialist

Biological Systems Engineering University of Wisconsin-Madison

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Why Apply Manure to Alfalfa?

• requires phosphorus and potassium • benefit from the micronutrients, particularly boron • removes large amounts of nitrogen from the field when

harvested as hay, and draw down nitrate levels within its root zone

• typically have low erosion, nutrient runoff and nutrient leaching potential

• opportunities for manure application throughout the year

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Land Base Declining

Area of

manure

application

Small

(1-99)

Medium

(100-199)

Large

(200-999)

Permitted

(>=1000) All

(Ha) 83 / 72 121 / 105 286 / 248 788 / 738 418 / 267

8 19 35 35 97

(Ha/AU) 1.07 / 0.97 0.88 / 0.77 0.68 / 0.59 0.40 / 0.34 0.65 / 0.54

8 19 35 35 97

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Application Timing

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Manure Application

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8

9

Draghose Lines

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Traveling Gun

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12

Center Pivot

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Risk vs. Distance

AGI: acute gastrointestinal illness, GN: gram negative bacteria, BB: bovine Bacteroides

1 in 100,000

1 in 10,000

1 in 1,000

1 in 100

Factor of 10

Factor of 100

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Manure Systems

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Manure Handling

Manure Collection

Manure Storage

Manure Processing/ Treatment

Land Application or

Final Treatment

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Anaerobic Digestion

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Covered Lagoons

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Dry Digestion

OshKosh Dry Digester, BIOFerm

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Small Scale Digesters

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Community Digesters Dane County Digester, 2011

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Agricultural Digesters

• 247 digesters in the U.S. • 37 in Wisconsin 35 different facilities All dairy facilities All liquid manure based systems

• ~300,000 metric tons CO2 eq/year removal Equal to:

63,000 passenger cars, or 322 million lbs of coal burned, or 83 wind turbines

• 229 WI dairy CAFO (>1,000 Animal units) facilities ~12% have digesters

Animals (No. of head) Operational

< 1,000 9

1,000-2,000 9

> 2,000 19

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AD Process Flow

Slurry

Biogas

Separator Digestate

Filtrate (liquid)

Fiber (solid)

Feedstock's

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End Products

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Odor

Swine Manure (Hansen et al. 2006, Applied Engineering in Agriculture)

• Malodorous VFA reduced 79-97%

• Odor reduced above undisturbed slurry store reduced

• Land application odor reductions: 17% AD 50% AD + SLS

(Orzi et al., 2015, Science of the Total Environment)

• Odors reduced 98%

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Bovine Polyomavirus

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1

10

100

1000

10000

100000

1000000

10000000

100000000

1E+09

Mea

n Pa

thog

en C

once

ntra

tion

(gc/

gm)

Farm #1

Farm #3

Farm #4

Farm #5

Farm #6

Farm #7

Farm #8

Bovine Polyomavirus

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Antibiotic Degradation

Alvarez et al., 2010, Bioresource Technology • Fate of antibiotics in pig manure in AD • oxytetracycline (OTC) and chlortetracycline (CTC) • Reduction in antibiotics over time, as well as

methane production • Antibiotics adsorbed to solids increasing duration

for destruction

• Many antibiotics to be tested

• Not many studies to date

• May increase intermediates

• Beef manure studies by Arikan (2006, 2007, 2008) found some degradation in initial component, increases in some intermediaries

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-60

-50

-40

-30

-20

-10

0

10

SLS AD AD+SLS

kg C

O2-

eq to

n-1

excr

eted

man

ure

CO2(f) CO2(b) N2O(f) N2O(b) CH4(f) CH4(b) NET

Global Warming Potential

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Thank You!