The document discusses the feasibility of installing anaerobic digesters at cattle operations in Colorado and the arid West region. It introduces anaerobic digestion and its benefits. It then addresses some of the feasibility problems in the region, such as cold winters and dry climates, which can impact waste quality and digester temperatures. An online decision support tool developed by Colorado State University is presented to help determine technical and economic feasibility of different anaerobic digestion technologies for various waste types and operation sizes.

1. FEASIBILITY OF
INSTALLATION OF
ANAEROBIC DIGESTERS AT
CATTLE OPERATIONS AND
DEMONSTRATION OF A
DECISION SUPPORT TOOL April 4, 2013
Sybil Sharvelle
Jeff Lasker
Catherine Keske
Lucas Loetsher

2. Presentation Overview
 Introduction to anaerobic digestion
 Feasibility problems in Colorado and arid West
region
 Online Decision Tool Developed by CSU

3. Anaerobic Digestion
High Carbon
Waste
Organics
 Acids
Acids 
CH4
High Nutrient
Low Odor
Product
Anaerobic Environment
Cogeneration
Hot Water
CH4
Green Power
Near Complete Pathogen Removoal

4. Uses for Methane Biogas
Methane Gas
Cogeneration
Electricity Hot Water
Purification to Supply
Natural Gas Lines Boiler
Purification
and
Liquifaction

5. Benefits
 Reduce greenhouse gas emissions
 Methane released from animal waste is captured
 Displacement of fossil fuels
 Improved waste treatment
 Pathogen reduction
 Carbon removal
 Odor control
 Renewable source of energy

6. Classic Lagoon Waste
Management

7. Simple – Covered Lagoon

8. High Tech – Above Ground,
Stainless Steel

9. AD Throughout US

10. Site Suitability
 Digester temperature ideal at 35o
C (98o
F)
 Locations with cold winters are not ideal
 Waste Quality
 Low solids content, < 17% solids
 Low inorganic content
 Soil
 Rocks
 Higher organic content, more energy content

11. Colorado – Cold Climate
Average Annual Minimum Temperature

12. Recommended Solids Content
Technology Recommended Waste
Solids Content
Covered Lagoon < 3%
Plug Flow 11 - 17%
Complete Mix 5 - 10%
Upflow Sludge Blanket 3 - 7%
Fixed Film
Dry Digestion
<3%
> 40%

13. Solids Content
 Waste management practice impacts solids
content
 Collection by flushing
 Concrete scrape
 Dry lot

14. Flush Collection
3-5% Solids

15. Scrape Collection on Concrete
Source: EPA AgSTAR
8-17% Solids

16. Dry Lot
Solids 20-90%

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

18. Problems with Dry Lot
Collection
 Dry scrape manure
 Contains rocks and sand
 Up to 80% TS in arid climate

19. Plug Flow
 Slow, requires high retention time
 Typically loaded in batches on farm
Rocks and sand will Settle and Build Up

20. Complete Mix
 Well mixed
environment
 Slightly faster rate
of digestion than
plug flow
High solids material can not be mixed
Sand/Rocks detrimental to moving parts

21. Technical Feasibility for AD
Technical
Feasibility
Good
Technical
Feasibility
Poor
Flush
Dairy
Concrete
Scrape Dry Lot

22. ADM Soybean
Processing
Biodiesel
Plant
Anaerobic
Digester
Frito Lay
Hot Soybean Oil
Cold Soybean Oil
Hog Waste
Food Waste
Biodiesel
Green Power
Codigestion: Planned Project in Indiana

23. Online Decision Tool Developed by CSU
 http://www.erams.info/AD_feasibility/

24. Learn About
AD
Determine
Technical
Feasibility
Determine
Economic
Feasibility
Select
Appropriate
Technology
Maintain AD
System
1 2 3 4 5

32. Summary
 AD can be a great waste management tool
 Care must be taken to ensure technical and
economic feasibility
 Online tool available for decision support

33. Acknowledgements
 Colorado NRCS
 Colorado Agriculture Experiment Station
 Colorado Governors Energy Office

34. Questions???