Manure Processing in Wisconsin

Troy Runge

Associate Professor

Biological System Engineering

UW Madison

1/26/2017

Topics

• Dairy Manure Issues

• Manure Separation Technologies & Rationale

• Research Work

• Separation technologies

• Nutrient separation

• Pathogen reduction

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Dairy in Wisconsin

• NASS for dairy

cows – 1.3

million cows

• 9990 farms

• 284 CAFO

permits

• $43.4 Billion

Economic

Impacthttp://www.wmmb.com/assets/images/pdf/WisconsinDairyData.pdf

http://dnr.wi.gov/topic/AgBusiness/CAFO/StatsMap.html

Cow “back-end output”Manure Produced by a 1,400 lb Cow/Day

Manure (lbs) 112

Manure (gal) 13.5

Total Solids (dry lbs) 14

Volatile Solids (dry lbs) 11.9

COD (lbs) 12.5

TK Nitrogen (lbs) 0.63

Total Phosphorus (lbs) 0.098

Total Potassium (lbs) 0.36

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1.3 million cows = 26.5 million tons/year

= 28 Trillion Btu from AD generated CH4

= generate ~4% of our electricity

Manure management in WI Rough rule of thumb - Dairy

farming

1 acre of tillable land per cow for feed

1 acre of tillable land per cow for manure spreading

Have enough land

~1 million cows

~10 million tillable acre

Issue has become one of cow density

http://en.wikipedia.org/wiki/Concentrated_Animal_Feeding_Operation

2012 Manure and Crop P

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Watershed-level Manure and Crop P

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Six Mile Pheasant Branch Creeks

Subwatershed area: 119 square miles

Crop area: 54% of subwatershed area

Avg. P assimilative capacity: 401 ton P/year

Avg. Manure P rate: 625 ton P/year

P manure/P crop = 1.56

Dane County

Area: 1,238 square miles

Crop area: 46% of county area

Avg. P assimilative capacity: 3,082 ton P/year

Avg. Manure P rate: 2,044 ton P/year

P manure/P crop = 0.66

Potential Manure Issues

Large amount manure: Environmental

& health risks

Water Quality concerns:

Leaching and runoff

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Farms and public concerns on pathogen

from application and recycling

Large Dairies = Large amount of manure

Mean Monthly Runoff, P-, N-. & Sediment Loss from Discovery Farms and Pioneer Farm 2003-08

Late Winter and Spring are the times of maximum

runoff, P-loss, N-loss and Sediment loss in Wisconsin

Runoff(inches)

Totalphosphorus(lb/ac)

TotalNitrogen(lb/ac)

Sediment(lb/ac)*(1/200)0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

September

October

November

December

January

February

March

April

May

June

July

August

Runoff(inches) Totalphosphorus(lb/ac) TotalNitrogen(lb/ac) Sediment(lb/ac)*(1/200)

Averages over 26 farm years

Fall Winter Spring Summer

Lets take a tour of the manure processing

Manure Process Tour

Reception

tank

Mixing

tankClarifier

Recycled

flush water

Digester

Bedding

DAF

High Solids

Lagoon

Screening

drums

Screw

press

Low Solids

Lagoon

Small

fibers

Biogas

SolidsLiquids

Barn

Maple Leaf Dairy Processing - Simplified

Manure Processing Rationale

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Solid/liquid separation

Nutrient fractionation

Pathogen reduction

Energy production

Separation Technologies

• Mechanical separation

• Screens

–Stationary inclined (static) screens

–Vibrating screens

–Rotating screens

• Presses

–Roller presses

–Belt presses

–Screw presses

• Centrifuges Source: Katers, John. 2008. Value-

added Opportunities for Separated

Manure Solids presentation.

• Gravity settling (passive)

• Clarifiers

• Settling Ponds

• Chemical addition to assist flocculation

Separation Rationale

• Produce sellable material – Organic fertilizer

• Improved land application logistics

• Recycling

• Process Water

• Bedding

• Enable nutrient fractionation

Recycling Water and Bedding

Maple Leaf Dairy

• Flush system – remove and transport manure

• Recycle fibers for bedding

Saves

• 25 million gallons of water

• 1.1 million tons of bedding

Enable Nutrient Fractionation

Ratio N P2O5 K2O

Manure 3 1 2

Liquid 4 1 3

Solid 2 2 1

• Create low solids stream with low P (high N) for use on

farm fertilizer.

• Create high solids stream with high P (low N) for transport

to low P land.

Removal of P out of Watershed

• Separation can creates high solids/high P fertilizer

• Can be dried and granulated

• Can be exported to:

• Low P land in watershed

• Outside watershed

• As organic fertilizer

• AD gas is envisioned as nice source of drying heat

• Envision Depot model for processing numerous smaller farms

TP Removal Comparison

Technology Initial TS (%)TP Removal

(%)

Settling Basin ~4 28

Screw Press variable 15-24

Centrifuge variable 60

Dewatering using

Geotextiles0.71 46

Inclined Plane variable 53

Screens 0.4-3.2 <17

Screens with

Polymers0.4-3.2 34-65

Chemical

Precipitation0.87-1.5 80-90

Polymer P separation• Significant additions of chemical

and polymer

• 80-90% TP removal

• Chemical additions can be high

Anaerobic Digestion Does NOT Remove P

Wright, et al. 2004. Preliminary Comparison of Five Anaerobic Digestion

Systems on Dairy Farms in New York State

0

100

200

300

400

500

600

700

800

900

AA DDI FA ML* NHTota

l Ph

osp

ho

rus

Co

nce

ntr

atio

n

(mg/

kg)

Facility

Total Phosphorus

Input

Output

Increase of 2%

Pathogen Management

• Manure Pathogen

Reduction

• Worker safety

• Herd health

• Recycling water

• Bedding

• Land application

• Worker safety

• Irrigation/Fertigation

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Pathogen Content: AD is the most effective in reducing

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0

1

2

3

4

5

6

RM PDAF AD DS L

Lo

g10

MP

N/m

L

Total coliform E. coli

RM: Raw manure

PDAF: Post-digester/Pre-DAF feed

AD: Post-digester/Pre-DAF effluent

DS: Post-digester/Pre-DAF sludge

L: Lagoon

Investigations into Pathogen Reduction with Polymers

Polymer

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Bacteria

TEM--E. Coli cells after incubated with PDCD

Polymer / Pathogen Experiment Results

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0

1

2

3

4

5

6

7

8

0 5 10 15 20

Lo

g (

MP

N/m

L)

Incubation Time (Hour)

50ppm

500ppm

2500ppm

Control

PAM Added in Buffer

0

2

4

6

8

10

0 5 10 15 20

Lo

g (

MP

N/m

L)

Incubation Time (Hour)

50ppm

500ppm

2500ppm

ControlPAM Added in TSB

0

2

4

6

8

0 5 10 15 20

Lo

g (

MP

N/m

L)

Incubation Time (Hour)

1ppm

5ppm

50ppm

500ppm

2500ppm

Control

PDCD Added in Buffer

0

2

4

6

8

10

0 5 10 15 20

Lo

g (

MP

N/m

L)

Incubation Time (Hour)

1ppm

5ppm

50ppm

500ppm

2500ppm

Control

PDCD Added in TSB

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Two-step separation (manure tests)

Treatment TS % Total Coliforms

(MPN/mL)

E. coli

(MPN/mL)

Digestate 4.08 7270 4880

PAM 1.15 261 186

PAM+PDCD 0.96 72 2

Also investigating Pathogen Reduction via Centrifugation

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2000 4000 6000 8000 10000

Red

ucti

on

Rate

Centrifuge Speed (×g)

Total coliform

Total solids

E. coli

Energy cost

Manure Processing Conclusions

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• Processing can effectively

• Manage Solids / Liquids / Nutrients

• Reduce Pathogens

• Allow water recycling and manure fiber production

• Polymers can be effective for manure flocculation

• Allows simpler systems (lagoons, screens, clarifiers) to

be used

• Can also reduce pathogen densities

• High speed centrifugation has a notable impact on solids

reduction and pathogen reduction but higher cost

Future Perspective

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• Manure Processing will become more predominant

• Dairy Farms will get bigger

• Value of fertilizer

• Precision agriculture practices

• Will allow solids to be moved further

• Move manure more cost effectively/safely to further fields

• Sell as organic fertilizers

• Export P nutrients out of “High P index” areas

• Need to have good techniques to use separated liquids

• High N,K and low P

• “Fertigation” is preferred method of land application by

farmers

WI Regulations on Manure Nutrient Management

Two laws are involved in manure nutrient management

• NR243 – Regulates manure management on CAFO’s

• NR214 – Regulates permanent spray fields & excludes manure

regulated under NR243

• NR214 usually is applied to permanent spray fields that can receive effluent nutrients

in excess of crop needs, such as from canneries, and require prohibitively expensive

environmental monitoring

• NR214 has been applied to non-permanent fertigation of raw manure to actual crop

needs or less than crop needs

Updates to regulations need to occur to keep pace with new

separation technologies.

trunge@wisc.edu

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