manure processing in wisconsin - wisconsin energy institute
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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
12
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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