1. January 20, 2009 Dr. Catherine Keske Dr. Sybil Sharvelle
Anaerobic Digestion: Turning One Man’s Trash Into Another Man’s Treasure
January 20, 2009
Dr. Catherine Keske
Dr. Sybil Sharvelle

2. Recovering Manure to Produce Energy
Benefits of Anaerobic Digesters
How Digesters Work
Trends and Feasibility
Economic Issues
How to Get Involved or Learn More
Questions
With all of the regulation and controversy surrounding manure management, it’s sometimes hard to think of manure as a “treasure trove”. However, through anaerobic digestion, we can convert manure from confined feeding operations into energy that can be used on the farm. This is particularly beneficial to dairies, which require a gIn many cases, extra energy can be supplied back to the grid. Even though the practice was first implemented in the 1970’s, updated engineering technology can convert waste into energy source with greater technical and economic efficiency than in the past. Dr. Sybil Sharvelle is a civil engineer from CSU, and she has conducted a significant amount of research on this process at Purdue in Indiana, where she earned her doctorate. She is going to speak about how these devices work in the Intermountain West. She will also speak about several of the trends in anaerobic digestion.

3. Benefits of Anaerobic Digesters
Environmental
Economic and Social
Production
Soil management
Manure management
Biogas production
Reduces environmental pollution
Water
Green house gases
Ammonia
On-farm energy generation (avoid electricity purchases)
May sell energy to utilities
Savings on bedding
Sale of composted solids
Carbon credits available
Renewable energy certificates
Odor control
Bedding savings: If a farm uses a solids separator, solids may be sold for bedding or used to replace current bedding materials.
Farms that switch from an anaerobic manure lagoon to a digester are eligible for carbon credits if the digester reduces methane emissions. (PA—4.41 carbon credits/lactating cow per year).

4. Anaerobic Digestion: How It Works
Green Power
Anaerobic Environment
Cogeneration
CH4
Organics  Acids
Acids  CH4
High BOD
Waste
Hot Water
High Nutrient
Low Odor
Waste

5. ADM Soybean Processing
Model Project: Quadra Project in Indiana
Green Power
Frito Lay
Biodiesel Plant
WE Can Do This in Colorado Too!
Cold Soybean Oil
Food Waste
Anaerobic Digester
Hog Waste
Hot Soybean Oil
ADM Soybean Processing

6. Waste Suitablility Low solids content, < 14% solids
Low inorganic content
Soil
Rocks
Higher organic content, more energy content

7. Colorado – Cold Climate
Average Annual Minimum Temperature

8. Covered Lagoon – Not an Option

9. Average Annual Precipitation In Colorado
Colorado – Dry Climate
Average Annual Precipitation In Colorado
Need to Find Nearby Source of Wastewater or Add Groundwater to Waste

10. Successful Digester at Dairy in Montana

11. Alternative Design - Two Stage Leachate Collection
Low Moisture
Manure and
Other
Waste
Organics
Anaerobic Digester
High Organic Leachate
Methane Gas

12. Costs of Anaerobic Digesters
Cost of the digester:
Approximately $1 million
Average life: 15 yrs. (Range: )
Cost of the solids separator:
Approximately $75,000
**Key to raising profitability**
Opportunity cost
Cost of your next best alternative
While the costs are high, it is also important to remember that “keeping the neighbors happy” (i.e. keeping the odors minimized) is also a benefit. Legal fees will significantly raise your operating costs. I like to remind people of this, as well.

13. Are Digesters Profitable? “Yes…”
Several models show profitability
Measured in cash flows associated with the investment
Critical to use a solids separator
Use the solids as a co-product
Bedding is the most economic use
Larger herds lead to economies of scale
Key element to profitability: Energy prices
2,000

14. “…But…Will a Digester Work for My Operation?”
Greater than 500 head (more than 1,000 head preferred)
Requires steady flow of manure (CAFOs)
Climate matters – the warmer the better
Must be able to use the biogas
“Community” digesters are an option
Pipelines transport waste to central site
Could consider other facilities (e.g. food processing)

15. “Yes, But…” Economic Considerations
Majority of studies conducted in the East
Profitability relies on carbon credits
$2 per metric ton of CO2
“Net positive gain” may include a net gain to the environment (not necessarily a net gain to the farmer/rancher)
Profitability critically depends upon energy prices

16. Want to Learn More? Contact Us!
Institute for Livestock and the Environment:
USDA Producer Workshop
2/19/09 York, Nebraska
AgStar:
Colorado Governor’s Energy Office:
Sponsoring feasibility studies
Contact us—we have several grant proposals pending and will begin implementing these programs in the very near future.

17. Questions?