Waste to Watts: Anaerobic Digestion of Livestock Manure (Sood)

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By: Dave Sood, Consultant, The presentation will cover key aspects of anaerobic digestion: -Methane Production from Manure -AD and Its Benefits -AD Process -Operating Conditions for AD -Manure Characteristics and Digester Types -AD and Water Quality -Manure Characteristics and Digester Types -Economic Analysis -AD in Europe -Why Digesters Fail? -Cold Climate Digesters -Key to Successful Digesters in Cold Climates -A success story & Carbon Credits: Haubenschild Dairy, Minnesota, USA


<ul><li> 1. 08/17/14 Waste to Watts: Anaerobic Digestion (AD) of Livestock Manure By: Dave Sood Consultant Email: davesood@aol.com </li></ul> <p> 2. 08/17/14 Waste to Watts - 2 Overview The presentation will cover key aspects of anaerobic digestion: Methane Production from Manure AD and Its Benefits AD Process Operating Conditions for AD Manure Characteristics and Digester Types AD and Water Quality Manure Characteristics and Digester Types Economic Analysis AD in Europe Why Digesters Fail? Cold Climate Digesters Key to Successful Digesters in Cold Climates A success story &amp; Carbon Credits: Haubenschild Dairy, Minnesota, USA 3. 08/17/14 Waste to Watts - 3 AD and its Benefits Odor and fly control Electricity, fuel for heating and Residual by-product Reduced pathogens; weed seed destruction Greenhouse Gas Reduction Others 4. 08/17/14 Waste to Watts - 4 Turkey Livestock Manure storage G till frsta sidan 5. 08/17/14 Waste to Watts - 5 The AD Process Acetate Hydrolytic &amp; Fermentative Bacteria Soluble Acids, Alcohols, &amp; Neutral Compounds Acid-Forming Bacteria Methane-Forming Bacteria Methane, C02, &amp; Trace Gases Acetate Organic Residue Acid-Forming Bacteria Acetate H2 H2, C02 Source: USEPA/AgStar 6. 08/17/14 Waste to Watts - 6 Methane Production from Manure 7. 08/17/14 Waste to Watts - 7 AD and Water Quality Existing Sources: Open Feedlots, Pasture, Stock piles, storage etc. N most monitored: CWA, EUs Nitrate Directives AD Converts Organic N to Ammonia better predictable Reduces runoff: By-product Residue more stable 8. 08/17/14 Waste to Watts - 8 Manure Characteristics &amp; Digester Types 9. 08/17/14 Waste to Watts - 9 Operating Conditions for AD Operating Parameter Typical Value Temperature Mesophilic 950 F Thermophilic 1300 F pH 7-8 Alkalinity 2,500 mg/liter (minimum) Retention time 10 30 days Loading Rate 0.15 0.35 lb VS/ft3 /day Biogas yield 3 8 ft3 /lb VS Methane content 60 70% Calorific Value 17 25 MJ/m3 10. 08/17/14 Waste to Watts - 10 Manure Digestion Issues High Capital Costs System Sizing: Technology Type, Permitting By-product Use (Electricity and Residues) Feedstock Supplements Type of Engine/Generator Cold Weather Comfort Level of Lenders Operator Knowledge and Training 11. 08/17/14 Waste to Watts - 11 Types of Digesters Plug-Flow Complete Mix Covered Lagoons Others 12. 08/17/14 Waste to Watts - 12 Family-size Biodigesters Most Popular are Chinese (Fixed dome) and Indian (Floating Dome) and their Modifications; (4 m3 and larger) Provide Energy for Lighting and Cooking to Over 23 Million, Mostly Rural Households Worldwide; Most Installations are in China, India and Nepal National Programs Sustainability have Often Required Subsidies, Easy Access to Credit, Market Development and Owner/operator Training. 13. 08/17/14 Waste to Watts - 13 Plug-Flow Digester AA Dairy in upstate New York, USA processes manure from around 600 cows and powers the farm with biogas product 14. 08/17/14 Waste to Watts - 14 Complete Mix Digester RCM Digesters - Colorado, US 15. 08/17/14 Waste to Watts - 15 Covered Lagoon 8,600 Hog Finishing Farm 16. 08/17/14 Waste to Watts - 16 Economic Analysis 500-Cow Dairy Farm (2004) System Components: Manure Digester, Settling tank, Solids Separator, Engine/Gen. Capital Costs (2001): 475,000 (includes 150 W Generator) O &amp; M Costs: $19,500/Yr. Miscellaneous: $18,000/year Revenues: Highly dependent on electricity rates, extent of avoided fertilizer purchases, extent of (free) labor by owner/operator etc. Payback Period: 4-6 years at 7.5 cents/kWh, Operator Labor, Some grants 17. 08/17/14 Waste to Watts - 17 AD in Europe Leading Countries: Denmark, Sweden, Germany, Others Current EU Deployment: 307 MW; potential 12,296 MW Types: Community Digesters, Heating/Mixing. Feedstock: Manure/dairy, fish, catering wastes etc. Supporting Policies: grants/premium elect. Price (15c kWh/Germany/v. high) Evolving/Improving 14 Euros/credit; U.S. Carbon Market: $4.10/credit (Values Change) 18. 08/17/14 Waste to Watts - 18 Why Digesters Failed? Poor Digester Design Incompatibility Each farm unique Poor Equipment Digester Engine Generator Toxic Substances Excessive NH3 (such as from urine) Harmful feed additives Poor Management Biological System Lack of knowledge/training/interest Poor Rate of Return Low price (3 cents/kWh) vs 7 cents/kWh Weak regulatory support 19. 08/17/14 Waste to Watts - 19 Few General Rule-of-Thumb Figures AD costs lower with greater animal nos. 13-14 pigs = One lactating cow 500-Cow Dairy Digester = 30-50k ft3 /day 1kW = 5-8 Cows = 40- 65 hogs/finishers = 1,000 birds/Layers Cow/methane/yr. = 200 liters of gasoline 1 cow/day = 1 - 2 kWh/day = 100 W for 22 hrs. 20. 08/17/14 Waste to Watts - 20 Key to Successful Cold Climate Digesters Manure collection, non-frozen Thermal system design (efficient/effective) Digester design (adequate size, insulation) Insulate exposed pipes Others, as needed 21. 08/17/14 Waste to Watts - 21 Cold Climate Operating Digesters Haubenschild Dairy, IL, 1999, 950 cows New Horizon, IL, 2002, 2,400 cows Stencil Farms,WI, 2001, 1,200 cows AA Dairy, NY, 1997, 1,000 cows Dairy Dev. Intl., NY, 1997, 1,000 cows. Matlink Farm, NY, 2001, 700 cows 22. 08/17/14 Waste to Watts - 22 Costs/Benefits Dairy Farm Start Date Capital Cost Electric Savings / Sales ($ / year) Hot Water Savings ($/year) Fiber Value ($/year) Haubenschild 1999 $335,000 $80,000 $20,000 No recovery Stencil 2001 $450,000 $40,000 $15,000 $40,000 New Horizons 2002 $875,000 $100,000 $19,000 $60,000 AA Dairy 1997 $311,500 $40,000 -- $10,000 DDI 2001 $325,000 None $30,000 $15,000 Matlink 2001 $625,000 $80,000 $15,000 $30,000 Source: USEPA/RCM Digesters Six Cold Climate Region Digesters in the U.S. 23. 08/17/14 Waste to Watts - 23 A Success Story: Haubenschild Dairy 24. 08/17/14 Waste to Watts - 24 Haubenschild Dairy, Princeton, MN 900 dairy cows, 1,000 acres, 4-generation family farm Plug-flow digester; gravity flow Total Cost (2005): $775,000; Generator: $375,000; O &amp; M/Year: By owner; 1 cents/kW Revenues:Variable, Electricity use on-farm and some area houses, Carbon credit/year (since 2003), credit for solids Funding Sources: 1/3rd owner; Rest: USEPA, MN State Agencies (0 % loan) 25. 08/17/14 Waste to Watts - 25 Engine-generator at Haubenschild, MN 26. 08/17/14 Waste to Watts - 26 Electricity Metering, Haubenschild Dairy, Connection to the Power Co. 27. 08/17/14 Waste to Watts - 27 By-product Storage Tank, Haubenschild, 28. 08/17/14 Waste to Watts - 28 Fuel Cell at Haubenschild Farm, MN 29. 08/17/14 Waste to Watts - 29 Digester Systems Biogas Flare Digester Building 30. 08/17/14 Waste to Watts - 30 Future Needs Include: Documenting Systems Performance/Costs Optimize Designs and Operations New Business Models/Electricity Pricing Farmer Training/Information Dissemination Country-specific needs including supporting policies. </p>


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