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Ann C. WilkieSoil and Water Science Department
University of Florida-IFAS
acwilkie@ufl.edu
Midwest Manure Summit
Lambeau Field, Green Bay, Wisconsin
February 16, 2011
Ecological Impacts on Future Farming
Fossil
Fuel
Cycle
CO2
Millions of years
Millions of years
Photosynthesis
exceeds
decomposition
Time, heat, pressure
Millions of years
Organic Matter Buried
under Sediments
Oil
CoalGas
CO2
About 100 years
Natural Resources
Waste
Greenhouse Gases
Biodiversity
EnergyHuman Health
Water
The Dimensions of Sustainability
Community
IMPACTS OF GLOBAL WARMING
• Climate change – shorter, warmer winters, earlier springs, changes in rainfall patterns, hotter temperatures affect growing seasons and animal health
• Plant health – many species are vulnerable to warmer temperatures and will respond differently to higher CO2 concentrations
• Wildlife – habitats may be transformed, degraded, or destroyed
• Human health – a warmer climate makes it easier for disease-bearing insects (ticks, mosquitoes) to spread and reproduce
ISSUES FACING FARMS
OF THE FUTURE
• Environmental regulations
– Water quality
– Air quality
– Odor
• Increasing cost of energy
• Some actions that address climate
change issues are simply good
management practices, such as:
– Efficient manure use
– Farm energy efficiency
– Cover cropping
– Development of local markets
NUTRIENT MANAGEMENT
• Land application is the most
sustainable option for manure nutrients
• Nitrogen
– Haber-Bosch process is energy intensive
• Phosphorus
– Finite resource
Steam
reformin
g
Source: wikipedia.com (http://en.wikipedia.org/wiki/File:Haber-Bosch-En.svg)
Haber-Bosch process for the production of Ammonia
Phosphate MiningSource: http://cdn.wn.com/pd/fb/2c/21c0d2bd610bbea9a2cae5319c20_large.jpg
Source: http://seekingalpha.com/article/182522-taking-stock-of-phosphorus-and-biofuels
Dairy Express
Nitrogen & Phosphorus
• Nutrient management plans
• Export excess – Where?
• Manure application for bioenergy crops?
• Fugitive nutrients– Wild algae
• Farmed algae– Domesticated algae
Matching Manure Nutrients to Crop Needs:
Feed Management
• Eliminating excessive phosphorus
and nitrogen in dairy cow feed
provides a cost savings by reducing
unnecessary supplements and
leads to decreased concentrations
of nutrients in manure.
• This approach is suitable for all
regions and dairies of all sizes.
• Eliminating excess crude protein (a major source of nitrogen) in cow
diets can decrease air emissions of ammonia.
• Dairy cows are typically fed 20-25% more phosphorus than
recommended by NRC. Reducing dietary phosphorus intake provides
major environmental benefits while saving producers money.
Phosphorus in dairy diets vs. NRC recommended levels (NRC, 2001)
Matching Manure Nutrients to Crop Needs:
Feed Management
Human-related Sources of Methane in the United States(% of total methane emissions)
• Unlike other greenhouse gases, methane can be used to produce energy since it is the major component (95%) of natural gas.
• Consequently, for many methane sources, opportunities exist to reduce emissions by capturing the methane and using it as fuel.
Electrical and/or
thermal energy
Biofertilizer
Organic
wastes Anaerobic
digestionBiogas
Solar energy
Animal husbandry
Biofuel production
Crop harvesting
Industrial processing
Human consumption
Photosynthesis
H2O
CO2
Biogas Cycle
Energy
crops
Natural gas
pipeline
Methanogenesis
Complex Organic Carbon
Monomers & Oligomers
Organic Acids
Acetate – H2 / CO2
CH4 + CO2
Hydrolysis
Acidogenesis
Acetogenesis
Anaerobic Digestion
COMPLEX
ORGANIC
MATTER
SIMPLE
ORGANICS
ACETATE
H2
/ CO2
METHANE and CARBON DIOXIDE
LOW ODOR EFFLUENT
LIQUEFACTION
PHASE
GASIFICATION
PHASE
ACIDOGENS METHANOGENS
STORAGE versus TREATMENT
• Unbalanced fermentation
• Intermediate metabolite accumulation
• Malodor
• Balanced fermentation
• Waste stabilization
• Permanent odor reduction
Benefits of Anaerobic Digestion
• Renewable energy
• BOD/COD reduction
• Odor reduction
• Pathogen reduction
• Nutrient conservation
• Greenhouse gas reduction
Odor Controland
Greenhouse Gas Mitigation
National Biodigester Programme
Cambodia (July 2010)
Biogas Burner – Cambodia (July 2010)
Renewable energy use reduces
CO2 pollution from fossil-fueled
power plants
More electricity from farm methane= Less electricity from fossil fuels= CO2 emission reductions
Electrical Grid
Anaerobic Digesters in the
U.S. Livestock Market
• 157 operating digesters
– 126 on dairies
– 24 on hog operations
Source: U.S. Environmental Protection Agency, U.S. Anaerobic Digester Status Report, October 2010.
Feedstocks
• Animal manures
• Agro-Industrial wastewaters
• Municipal wastewaters
• Municipal solid wastes
• Biofuels by-products
• Energy crops / crop residues
Gases
Kerosene
Gasoline
Diesel
Engine Oil
Fuel Oil
Tarmac
Crude Oil
Oil Refinery
Biogas
Manure
Fibrous
Solids
Liquid
Cellulose Biofuel
Peat substitute
Compost
Gasification
AnaerobicDigestion
Biofertilizer
Crops
AlgaePress cake
Oil Biodiesel
Methane
Electricity
Animal feed
Manure Biorefinery
Solids Separation
Biofuels
• The rapid growth in biofuels production
has significant impacts that must be
managed:
– Energy demand
– Wastewater production
– Water and Land use
– Air emissions
• Larger facilities mean increased
wastewater and by-product volumes
CLOSED
LOOP
DAIRY / FEEDLOT BIOETHANOL PLANT
ANAEROBIC DIGESTER
MANURE BIOGAS
FEED
STILLAGE
Co-location Synergies
TRANSESTERIFICATION
PRESS
CAKE
BIODIESEL
Oil
pressing
CRUDE
GLYCEROL
Washing
WASTE
OIL
VIRGIN
OIL
CRUDE
BIODIESEL
WASHWATER
METHANOL + KOH
Anaerobic
Digestion
BIOGAS
OIL CROPS
ALGAE
Centralized Farm Oil Refinery
Periphyton Bio-Reactors
Biogas
High-Nutrient
Wastewater
Anaerobic
Digestion
Algal Sludge
Algal Cake
Biodiesel
Glycerin
Bioregional
Processor
Clean
Water
Biofertilizer
WATER
SUNLIGHT
Energy
Crops
Biogas
Plant
Biofertilizer
CO2
CO2 WATER
Methane
Green Grass to
Green Gas
Moo-ving to Sustainability
• Biogas
– Environmental compliance
– Carbon credits
• Manure nutrients
– Biofertilizer for bioenergy crops
• Biodiesel
– Fuel and Feed
Photovoltaic panels at Limes Farm, Bourne, UK
Source: Smye Holland Associates Limited, Peterborough, UK. 12/23/2010
http://www.smye-holland.com/SmyeHolland_NewsDetail.aspx?PressRelease=2918
Photovoltaic panels at Red Fire Farm, Granby, MA.
Source: Daily Hampshire Gazette, Northampton, MA. 9/13/2010
http://www.gazettenet.com/2010/09/13/seeds-change
Wind machines on farm.
Source: Farm CPA Today, 7/20/2009
http://www.farmcpatoday.com/2009/07/
Israeli farmers use barn roofs to generate electricity.
Kfar Vitkin, Israel. 11/11/2009
Source: http://www.life.com/image/93252134
Glazed flat-plate collectors for an on-farm milk processor
(Enerworks & Ronnybrook Farms).
Source: Ministry of Agriculture Food & Rural Affairs, Ontario, CA.
http://www.omafra.gov.on.ca/english/engineer/facts/sol_wat.htm
Further Reading …
• Our Ecological Footprint: Reducing Human Impact
on the Earth. Mathis Wackernagel & William Rees
(1995).
• Enriching the Earth: Fritz Haber, Carl Bosch, and
the Transformation of World Food Production.
Vaclav Smil (2000).
• Beyond Oil: The View from Hubbert’s Peak.
Kenneth S. Deffeyes (2006).
• Eating Fossil Fuels: Oil, Food and the Coming
Crisis in Agriculture. Dale Allen Pfeiffer (2008).
Ann C. WilkieSoil and Water Science Department
University of Florida-IFAS
acwilkie@ufl.edu
Midwest Manure Summit
Lambeau Field, Green Bay, Wisconsin
February 16, 2011
Ecological Impacts on Future Farming
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