Transcript Manure – A Multi-Purpose Resource: ”Things are Changing in

Manure – A Multi-Purpose Resource:
”Things are Changing in the Barnyard!”
Bruce T. Bowman
Expert Committee on Manure Management
Canadian Agri-Food Research Council
London, ON
Presented to:
Nova Scotia Soil & Crop Improvement Association
February 22, 2005
Presentation Outline
 Conserving and Recycling Manure Nutrients
 Relevance and links to manure processing
 Manure Processing – Anaerobic Digestion
 Renewable Energy & Livestock Farming
 New Opportunities – rural revitalization,
diversification, and energy independence
 Micro CHP distributed power generation
Manure Management
Priority Issues
Three priority issues to manage:
 Nutrients
 Odours
 Pathogens
............................. but also …….
 Water volumes
 Carbon = Energy $$$
Context: Presentation will be more applicable for larger confined
livestock operations than for grazing-based systems.
Conserving Nutrients:
Gaseous Nitrogen losses from Manure
 Two major loss pathways:
 As volatile ammonia (NH3)
 As nitrous oxide (N2O)
(greatest impact of GHGs – 310x effect of CO2)
 Gaseous losses can occur at any stage of
handling with continued exposure to air.
Conserving Nutrients:
Ammonia losses from Manure
 Ammonium (NH4+) - non-volatile;
 pH 9.4
pH 7.5
pH 7.0
Ammonia (NH3) - volatile
[NH3] / [NH4+] = 0.50 (50%)
[NH3] / [NH4+] = 0.018 (1.8%)
[NH3] / [NH4+] = 0.0056 (0.56%)
@(20°C)
Keep pH near 7 (neutrality) to minimize NH3 losses
 Ammonia losses are also rapid from bare floors; Remove
manure when fresh to closed storage to minimize NH3 losses.
Conserving Nutrients:
Ammonia losses from Manure
 Why should we minimize these losses?
 Increasing replacement costs for commercial N = $$$
- Urea production  energy intensive + GHG emissions
 Ammonia emissions receiving more scrutiny from both
animal and human health perspectives
(smog potential – lower Fraser Valley in BC)
 Ammonia - a toxic substance under CEPA (Can. Env.
Protection Act)
 Secondary source for nitrous oxide (N2O) production.
Conserving Nutrients:
Nitrous Oxide Production
Nitrification
Oxidation
ammonium
nitrate
Denitrification
Nitrification &
denitrification are
biological processes
30° - 40°C
Reduction**
nitrate
nitrogen gas
Conserving Nutrients:
Reducing Nitrous Oxide Emissions
 Maintain aerating conditions - in manure storage &
handling, or in soil following land application.
(e.g. avoid application on saturated soils – restricted aeration;
 Reduce Exposure to Air in Storage - negative air
pressure covers on lagoons reduce gaseous losses.
 Reduce “labile carbon” content in manure
(energy source for microbes) – 50% of carbon in digested
manure is converted into biogas, depriving soil microbes of
this energy source following soil application  less N2O
production. (minimal negative impacts on soil quality)
Trends in the Fertilizer Industry
-- Post WWII (1945) - Cheap & plentiful mineral fertilizers helped spur
intensification and specialization in production
agriculture after 1945.
 Cereal production (cash-cropping) is often separate from
livestock production, relying only on mineral fertilizers.
(Mixed farming systems are usually more sustainable).
 Started to create some regional nutrient surpluses
(Quebec, North Carolina, Chesapeake Bay area).
 Consequence: Nutrients in livestock manures originating
from imported feeds - not recycled back to source for next
cash-crop production cycle.
LARGE-SCALE NUTRIENT FLOWS
Recycling Nutrients & Organic Matter
Nutrient inputs
Food
Products
Manure
Cereal Production
Human
Consumption
Nutrients
O.M.
Annual
Mineral
Fertilizer
Additions
Nutrients & O.M. NOT recycled
Regional nutrient excesses
Wastes
Local Farm
Landfills
Reasons to Recycle
Livestock Nutrients
 Many confined livestock operations import more
nutrients than they export, resulting in nutrient
accumulations.
(US studies - NE, WA, PA) … not sustainable in long term.
 Can not continue to increase N loadings and still
maintain current nitrate water quality standards.
 Human activities doubled global N fixation rate in 20th century.
 In many countries, P is considered a non-renewable
resource – finite supply, some of which have high
heavy metal contents (e.g. Cd in phosphate from Idaho).
Whole Farm Nutrient Balances
(Budgets)
 Balancing Nutrient INPUTS & OUTPUTS
at farm-scale or at small watershed-scale.
– Next stage in Nutrient Management Planning &
Source Water Protection.
 As more precise nutrient management planning is
implemented, many farmers will discover nutrient
surpluses somewhere within their land base.
 Recent Studies in U.S.A. show that majority of farms
studied have nutrient surpluses, esp. Nitrogen.
(INPUT/OUTPUT > 1.5)
(Koelsch & Lesoing, 1999; Cogger, 1999)
Managing On-Farm
Nutrient Surpluses

Three Options (singly or in combination)
1.
Reduce nutrient inputs to balance nutrient
exports from the land base (e.g. improved feeding
strategies – nutrient use efficiency e.g. phytase).
2.
Increase land base for applying manure
nutrients (buy, rent more land or contract for
exporting excess manure; Exporting liquid manure
nutrients < 15 km radius (economics).
3.
Export surplus nutrients from the farm in the
form of value-added products (new revenue organic fertilizers/amendments).
Requirements for Exporting
Surplus Livestock Nutrients
 The need to export surplus nutrients will increase
with further intensification of livestock operations.
 Criteria for exporting manure nutrients:
 Odour-free
 Pathogen-free
 Dewatered (dried) for transportation
Manure processing can address these issues.
What is Manure Processing?
 ….“Treating” the entire manure volume to reduce
odours & pathogens.
Two best technologies:
 Anaerobic digestion – high cost, greater revenue
 Composting – low-cost, limited revenue
 Manure processing can provide the farmer with
increased flexibility for managing surplus nutrients,
while solving other environmental problems.
Why Digest Manure?
Potential Benefits
Environmental
Economic
 Reduce odours & pathogens
- flexibility to export surplus nutrients
 Conserve nutrients (N)
- reduce mineral fertilizer use
 Reduce emissions
- GHGs & ammonia
 Renewable energy generation
- energy independence
 Export surplus Livestock nutrients
 Emission reduction trading credits
 Tipping fees – food-grade wastes
- 20 – 25% energy boost
Societal
 Reduce siting / zoning problems
Regain public support
 Opportunity for new rural partnerships
Balancing Issues
in a Sustainable Farming Operation
1. Yield/Productivity
(economics)
Pre-1965
Societal Concerns
2. Environmental Protection
Since 1970s  2-D
Both are science-based
3. Societal Concerns
Since 1990s  3-D
 Perception-based, emotional
 Can over-ride other 2 factors.
 Opposition difficult to reverse
once initiated
Anaerobic Digestion
Processes
Anaerobic Digestion
A Few Facts
 Mimicking fermentation in a ruminant stomach.
(most digesters are mesophylic ~ 37°C – body temp.)
 Kills weed seeds – reduces herbicide use.
 pH often increases about 0.5 unit during digestion.
 Closed system – no nutrient or gaseous losses (e.g. N)
- closer N:P ratio than with raw manure
 About 50% of carbon  biogas (CH4 + CO2, 65:35, tr. H2S)
- (nutrients in more plant available, predictable form)
Anaerobic Digestion
…….. More Facts
 Certain antibiotics can HALT digestion processes
 Solids range: up to ~ 13% (easily pumpable)
 Hydraulic Retention Time: (processing time):
- 20–35 days @ 37°C
 Odour Reduction: ~ 90 % or more
 Pathogens Reduced to:~ 1/1000 – 1/10,000 (mesophylic);
- Eliminate pathogens by pasteurizing (1hr @ 70°C)
Managing Dead Stock
A Waste + Nutrient Issue
 Currently a waste issue that costs the farmer to
manage – end products have lost their value since
BSE crisis - can’t recycle animal protein through feed
system – e.g. bonemeal has lost much of its value
 Current disposal methods have limitations
 Burial – limited capacity, point source pollution potential
 Incineration – N and C lost, minerals?; emission issues
renewable energy recovery possible
 Composting – cost recovery for composted solids
Managing Dead Stock
A Waste + Nutrient Issue
 Anaerobic Digestion – best solution for deadstock
and for animal rendering – 2 valuable end products
 Renewable energy recovery (heat, electricity)
 Organic fertilizer/amendment end product
 Conserves N, P & some C for recycling back to land
 Minimizes odour problems; eliminates pathogens
 Pre-treatment = shredder + Pressure/Temperature
- treated waste virtually all digestible
- possible elimination of BSE prions
Types of Anaerobic Digesters
Courtesy of: US EPA AgStar Handbook
Components of a Complete Mix
Mesophillic Digester
Hydraulic reactor
Buffer tank - Premix
Remove foreign
materials
Combined Gas
+ Effluent Storage
Co-Gen Set
Grid
Courtesy: Rentec Renewable Technologies
Manure Processing
Anaerobic Digestion

Low Tech

High Tech
Barriers to Adoption
of Anaerobic Digesters
1.
Initial Investment / Payback Issues
2.
Regulatory Issues
3.
Reliability, Trust & Expertise
4.
Managing Complexity
Overcoming
Barriers to Adoption
of Anaerobic Digesters
1.
Initial Investment / Payback Opportunities

$300K - $5M, depending on scale of operation
– Plant Life = 20 – 30 yr
– Payback = <10 yr (electricity, solids sales, emission credits)

Policy changes - Environmental Loan
Guarantees & Tax Incentives
– to assist farmer in managing initial capital risks

Payback - What is the value of odour/pathogenfree manure products to the farmer? – change
from societal opposition to support (partnerships)
Overcoming
Barriers to Adoption
of Anaerobic Digesters
1. Potential Revenue Streams
 Electricity Purchase Agreements
– Net Metering, Dual Metering – Peak Demand Generation
– Nova Scotia, Ontario, Saskatchewan - leading provinces
– may be sufficient to be energy independent;
delivered power ~ 2 x generating costs (ON = 12 - 15¢/kwh)
 Sale of Processed Solids/ Org. Fertilizers
– excess nutrients exported – promotes nutrient re-use
 Emission Trading System currently developing
- sell credits for reducing emissions
- current value of e-CO2 ~ $10/tonne
 Tipping Fees for Receiving Food-Grade Wastes
– boost biogas output (20 – 30%)  increases revenue
Overcoming
Barriers to Adoption
of Anaerobic Digesters
2.
Regulatory Issues

Electrical generation – interconnects / net metering
Power Utilities starting to change policies for small
renewable energy generators (up to 500 kw)

Off-farm biomass inputs (boost biogas production)

Managing emissions / discharges
can result in C. of A.s – regulations being changed to allow
<20% food-grade wastes
Biogas flare, potential ghg, or liquid discharges

Fertilizer/amendment products (quality, certification)
– labeling requirements
Overcoming
Barriers to Adoption
of Anaerobic Digesters
3. Reliability, Trust & Expertise
 Small installed digester base in Canada
(12 – 18 in advanced design or already built)
 Limited knowledgeable Canadian design/build firms
- limited track record
 Demonstration Program – AAFC/NRCAN - 3 yr - Energy
Co-generation from Agricultural/Municipal Wastes (ECoAMu)
4 digesters (AB – Beef; SK – Hogs; ON – Beef; QC - Hogs)
ManureNet
http://res2.agr.gc.ca/initiatives/manurenet/en/hems/ecoamu_main.html
Overcoming
Barriers to Adoption
of Anaerobic Digesters
4. Managing Complexity
 A.D. adds yet another new technology to be
managed by farmer – Time; Skill-sets
 Service agreements
 Co-Gen – Power Utility – electricity export
 Remote monitoring & process control in realtime – practical technology now available
Integrated Livestock Farming System
Closed Loop Single Farm Energy Centre
Nutrient inputs
- 15% feed costs
<20% Off-Farm
Food-Grade Wastes
Nutrient
Recycling
Revenue #2
Electricity
Export
Anaerobic
Cereal
Production
Digester
Co-gen
Electricity
Revenue #1
Nutrient
Export
Non-Ag Uses
Home gardens
Turf/golf
Parks
Heat
Nutrient
Surplus
Organic
Fertilizer
CO2
Surplus
Co-Located
Industries
Bio-ethanol plant
Greenhouses
(Veg., Flowers)
Fish Farm
Local Farm
Revenue #3
Optional
A Centralized Co-operative Rural Energy System
Potential Components
Dewatered
Digestate
Liquid
Digestate
Organic
Fertilizers
water
Co-gen Resource Centre
Food Grade
Organics
Local
Municipal
Organics
Electricity
Heat
Rendering,
Deadstock
Wet Distillers Grain - 15% savings
CO2
Clean Water
Co-Located
Industries
Greenhouses
(Veg., Flowers)
Fish Farm
Slaughterhouse
Bio-ethanol plant
Challenges Facing
Confined Livestock Operations
Energy
 Increasing price volatility (The China factor)
 Less reliable supplies (Declining fossil reserves)
 Increasing N fertilizer costs
Environment
/ Health
 Increasing regulations – nutrients, pathogens
 Municipal waste issues (biosolids)
 Rendering / deadstock – limited uses/value
 GHG emission reductions – Kyoto protocol
 Increasing livestock intensities – odour
Economics
 Continuing vulnerability of farm incomes
 Increasing costs of compliance
Re-Defining
Confined Livestock Farming
 Future livestock farming will be structured around
bio-energy  energy independence using co-gen
technologies.
 Facilitate conservation and recycling of resources
(nutrients, carbon = $$$)
 Create greater diversification of income
 income stabilization (independent from commodity prices!)
- Green Electricity
- Processed manure solids
- Emission Trading Credits
- Co-located integrated industries
- Tipping fees for food-quality wastes (energy boost)
Re-Defining
Confined Livestock Farming
 Substantially reduce existing environmental issues
– reduced odours, pathogens  greater societal support
– greater flexibility for applying/selling processed manure
 Strengthen rural economy utilizing more local inputs
(employment, resource inputs – biomass crops)
- Municipality can be a partner (wastes, buy energy)
- Farm co-ops take increased control of rural businesses
Produce value-added products on-farm
- Reduced transportation costs for manufacturing (bio-based)
Farm Bio-Energy Centres
As Integrators & Facilitators
GHG reductions
Deadstock
Income
Stabilization
Odours Environmental
Solutions
Pathogens
Nutrient
export &
Recycling
Reduce
herbicide
use
Farm Bio-Energy
Energy
Independence
Municipal
Organic wastes
Rural Revitalization
Heat
Electricity
Clean water
CO2
Electricity
Manure solids
Emission
credits
Tipping fees
Independent
Of
Livestock
prices
Co-located industries
Local biomass inputs
Considering a Digester?

First Steps (courtesy of Penn State Univ. Extension)

Do your homework — read background info on biogas

Seek preliminary technical assistance

Talk to digester owners

Talk to your electric power company – safety/connects

Investigate potential financial incentives such as tax credits
and loans

Talk to digester system designers and installers
Selecting a Digester - ManureNet
http://res2.agr.ca/initiatives/manurenet/en/man_digesters.html#Selecting
Micro CHP
(Combined Heating and Power)
Distributed Power Generation
Electricity + Heat generated at each residence
Small engine + generator  replace furnace & water heater
85 % efficiency
Grid
Micro CHP
(Combined Heating and Power)
Distributed Power Generation
Centralized GasFired Plant
Micro CHP
100
100
57
<15
4-7
0
39
20
Useful Heat Energy
0
65
Net Useful Energy
36-39
85+
INPUT
Waste Energy
Line Losses
Electricity
Micro CHP
(Combined Heating and Power)
Advantages

More efficient use of resources (15% vs 60% loss)
(39 vs 85 % efficiency)






Micro CHP units run on natural gas or biogas
Excess electricity exported to grid (10 kw units - $$)
Blackout & Terrorist proof (totally distributed generation)
Significant GHG reductions
Almost eliminate line losses (electricity used on-site)
In Ontario – 2 million homes would produce 10,000 Mw
– equivalent to several nuclear power plants
No environmental assessments required – minor impacts
 Several thousand units being tested in Europe & Japan;
USA senate holding hearings on technology potential

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