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
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Manure – A Multi-Purpose Resource : ”Things are Changing in the Barnyard!”
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. - PowerPoint PPT Presentation
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Manure – A Multi-Purpose Resource:”Things are Changing in the Barnyard!”
Bruce T. Bowman
Expert Committee on Manure ManagementCanadian 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
Three priority issues to manage:
Nutrients Odours Pathogens
............................. but also …….
Manure ManagementPriority Issues
Context: Presentation will be more applicable for larger confined livestock operations than for grazing-based systems.
Water volumes Carbon = Energy $$$
Two major loss pathways:
As volatile ammonia (NH3)
As nitrous oxide (N2O) (greatest impact of GHGs – 310x effect of CO2)
Gaseous losses can occur at any stage of handling with continued exposure to air.
Conserving Nutrients:Gaseous Nitrogen losses from Manure
Ammonia losses are also rapid from bare floors; Remove manure when fresh to closed storage to minimize NH3 losses.
Why should we minimize these losses?
Increasing replacement costs for commercial N = $$$- 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:Ammonia losses from Manure
Conserving Nutrients:Nitrous Oxide Production
Oxidation
Reduction**
Nitrification & denitrification are biological processes 30° - 40°C
Nitrification
Denitrification
ammonium nitrate
nitrate nitrogen gas
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.
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).
Reasons to Recycle Livestock Nutrients
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)
Whole Farm Nutrient Balances(Budgets)
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).
Managing On-Farm Nutrient Surpluses
Criteria for exporting manure nutrients: Odour-free Pathogen-free Dewatered (dried) for transportation
Manure processing can address these issues.
Requirements for Exporting Surplus Livestock Nutrients
The need to export surplus nutrients will increase with further intensification of livestock operations.
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.
Societal
Reduce siting / zoning problemsRegain public support
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
Anaerobic Digestion – best solution for deadstock and for animal rendering – 2 valuable end products
Renewable energy recovery (heat, electricity) Organic fertilizer/amendment end product
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)
2. Regulatory Issues
Electrical generation – interconnects / net meteringPower Utilities starting to change policies for small renewable energy generators (up to 500 kw)
Off-farm biomass inputs (boost biogas production)can result in C. of A.s – regulations being changed to allow <20% food-grade wastes
Managing emissions / dischargesBiogas flare, potential ghg, or liquid discharges
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)
Future livestock farming will be structured around bio-energy energy independence using co-gen technologies.
Facilitate conservation and recycling of resources (nutrients, carbon = $$$)
Create greater diversification of income income stabilization (independent from commodity prices!) - Green Electricity- Processed manure solids- Emission Trading Credits- Co-located integrated industries- Tipping fees for food-quality wastes (energy boost)
– reduced odours, pathogens greater societal support
– greater flexibility for applying/selling processed manure
Strengthen rural economy utilizing more local inputs (employment, resource inputs – biomass crops)- Municipality can be a partner (wastes, buy energy)- Farm co-ops take increased control of rural businesses Produce value-added products on-farm- Reduced transportation costs for manufacturing (bio-based)
First Steps (courtesy of Penn State Univ. Extension)
Do your homework — read background info on biogas
Seek preliminary technical assistance
Talk to digester owners
Talk to your electric power company – safety/connects
Investigate potential financial incentives such as tax credits
and loans
Talk to digester system designers and installers
Considering a Digester?
Selecting a Digester - ManureNethttp://res2.agr.ca/initiatives/manurenet/en/man_digesters.html#Selecting
Micro CHP (Combined Heating and Power)
Distributed Power Generation
Electricity + Heat generated at each residenceSmall engine + generator replace furnace & water heater
Grid
85 % efficiency
Micro CHP (Combined Heating and Power)Distributed Power Generation
Centralized Gas-Fired Plant Micro CHP
INPUT 100 100
Waste Energy 57 <15
Line Losses 4 - 7 0
Electricity 39 20
Useful Heat Energy 0 65
Net Useful Energy 36-39 85+
More efficient use of resources (15% vs 60% loss) (39 vs 85 % efficiency)
Micro CHP units run on natural gas or biogas Excess electricity exported to grid (10 kw units - $$) 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