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

pH 9.4 [NH3] / [NH4+] = 0.50 (50%) @(20°C)pH 7.5   [NH3] / [NH4+] = 0.018 (1.8%)pH 7.0   [NH3] / [NH4+] = 0.0056 (0.56%)

Keep pH near 7 (neutrality) to minimize NH3 losses

Conserving Nutrients:Ammonia losses from Manure

Ammonium (NH4+) - non-volatile; Ammonia (NH3) - volatile

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)

Conserving Nutrients:Reducing Nitrous Oxide Emissions

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.

Food Products

HumanConsumptionCereal Production

LARGE-SCALE NUTRIENT FLOWSRecycling Nutrients & Organic Matter

AnnualMineral

FertilizerAdditions

Nutrients & O.M. NOT recycled

Regional nutrient excesses

Local Farm

Manure

Nutrients O.M.

Wastes

Landfills

Nutrient inputs

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

Opportunity for new rural partnerships

Economic

Renewable energy generation

- energy independence

Export surplus Livestock nutrients Emission reduction trading credits Tipping fees – food-grade wastes

- 20 – 25% energy boost

Environmental

Reduce odours & pathogens - flexibility to export surplus nutrients

Conserve nutrients (N)- reduce mineral fertilizer use

Reduce emissions - GHGs & ammonia

Why Digest Manure?Potential Benefits

Yield / Productivity

Environmental Protection

S

oci

etal

Co

nce

rns

Balancing Issues in a Sustainable Farming Operation

1. Yield/Productivity (economics)

2. Environmental Protection

Both are science-based

3. Societal Concerns

Perception-based, emotional

Can over-ride other 2 factors.

Opposition difficult to reverse once initiated

Pre-1965

Since 1970s 2-D

Since 1990s 3-D

Anaerobic DigestionProcesses

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

A Few 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)

Anaerobic Digestion

…….. More Facts

Managing Dead StockA 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

Anaerobic Digestion – best solution for deadstock and for animal rendering – 2 valuable end products

Renewable energy recovery (heat, electricity) Organic fertilizer/amendment end product

Managing Dead StockA Waste + Nutrient Issue

Pre-treatment = shredder + Pressure/Temperature - treated waste virtually all digestible

- possible elimination of BSE prions

Conserves N, P & some C for recycling back to land Minimizes odour problems; eliminates pathogens

Types of Anaerobic Digesters

Courtesy of: US EPA AgStar Handbook

Components of a Complete Mix Mesophillic Digester

Courtesy: Rentec Renewable Technologies

Buffer tank - Premix

Hydraulic reactor

Combined Gas + Effluent Storage

Co-Gen Set

Remove foreign materials

Grid

High Tech

Manure Processing Anaerobic Digestion

Low Tech

1. Initial Investment / Payback Issues

2. Regulatory Issues

3. Reliability, Trust & Expertise

4. Managing Complexity

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/pathogen-free manure products to the farmer? – change from societal opposition to support (partnerships)

Overcoming Barriers to Adoption

of Anaerobic Digesters

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 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

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)

OvercomingBarriers to Adoption

of Anaerobic Digesters

ManureNet

http://res2.agr.gc.ca/initiatives/manurenet/en/hems/ecoamu_main.html

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 real-time – practical technology now available

OvercomingBarriers to Adoption

of Anaerobic Digesters

Revenue #2Electricity

Export

Revenue #1Nutrient Export

Integrated Livestock Farming System

Closed Loop Single Farm Energy Centre

Local Farm

Organic Fertilizer

Non-Ag UsesHome gardens

Turf/golfParks

Nutrient

SurplusCo-Located Industries

Bio-ethanol plantGreenhouses

(Veg., Flowers)Fish Farm

Cereal Production

- 15% feed costs

Revenue #3Optional

Nutrient

Recycling

Anaerobic

Digester

<20% Off-Farm Food-Grade Wastes

Nutrient inputs

Co-gen

SurplusElectricity

Heat

CO2

Co-Located Industries

Greenhouses(Veg., Flowers)

Fish FarmSlaughterhouse

Bio-ethanol plant

A Centralized Co-operative Rural Energy System

Potential Components

LiquidDigestate

Resource Centre

Electricity

Clean Water

Heat CO2

DewateredDigestate

Food GradeOrganics

Local MunicipalOrganics

Rendering, Deadstock

Organic Fertilizers

water

Co-gen

Wet Distillers Grain - 15% savings

Challenges Facing Confined Livestock Operations

Increasing price volatility (The China factor)

Less reliable supplies (Declining fossil reserves) Increasing N fertilizer costs

Continuing vulnerability of farm incomes Increasing costs of compliance

Increasing regulations – nutrients, pathogens Municipal waste issues (biosolids) Rendering / deadstock – limited uses/value GHG emission reductions – Kyoto protocol Increasing livestock intensities – odour

Energy

Environment

/ Health

Economics

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)

Re-Defining Confined Livestock Farming

ElectricityManure solids

Emission credits

Tipping fees

Heat Electricity

Clean waterCO2

Municipal Organic wastes

Co-located industriesLocal biomass inputs

OdoursPathogens

Nutrient export & Recycling

Reduce herbicide

use

GHG reductionsDeadstock

Farm Bio-Energy CentresAs Integrators & Facilitators

EnvironmentalSolutions

IncomeStabilization

Rural Revitalization

Farm Bio-Energy

EnergyIndependence

IndependentOf

Livestockprices

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

Micro CHP (Combined Heating and Power)

Advantages

Resource Information on

http://res2.agr.gc.ca/initiatives/manurenet/manurenet_en.html

6,000 external web links Several hundred digital technical/research reports

Manure TreatmentDigester CompendiumNutrient RecoveryAmmonia EmissionsNutrient ManagementEnvironmental IssuesGHG EmissionsOdour ManagementLand Application

Storage & HandlingHousing / FeedlotsFeeding StrategiesCodes, Acts,

RegulationsHealth & SafetyLinksDigital LibraryExpertiseEnvironmental Archive

(150 digital reports)