Full proceedings at: http://www.extension.org/72952 While EPA AGSTAR has long supported the adoption of anaerobic digestion on dairies and swine farms, they have not historically focused on the use of anaerobic digestion on egg laying and other poultry facilities. This has been because the high solids and ammonia concentrations within the manure make anaerobic digestion in a slurry-based system problematic. Development of enhanced downstream ammonia and solids recovery systems is now allowing for effective digestion without ammonia toxicity. The process also generates dilution water, avoiding the need for fresh water consumption, and eliminating unwanted effluent that needs to be stored or disposed of to fields. The system produces high-value bio-based fertilizers. In this presentation, a commercial system located in Fort Recovery Ohio will be used to detail the process flow, its technologies, and the co-products sold.

1. Poultry Digestion: Emerging Farm-
Based Opportunity
Craig Frear, Chad Kruger
Center for Sustaining Agriculture and
Natural Resources
Washington State University
Photo: Andgar

2. Outlines
1. Poultry Statistics/Ammonia
2. Concerns with AD of poultry
3. Example
4. Conclusion
Photo: DVO

3. Poultry Statistics/Ammonia
Photo: Jim Jensen

4. Poultry Statistics: Layers
Layers/Broilers
• 387 farms with 269 M or 77% of
market~700K mean (Layers) and 33,000
farms with 8.5 B or 67% of market~250K
mean (Broilers).
• 20-30 lbs. fresh manure per day per 100
layers at 75% moisture
• Naturally dry during storage, achieving 20-
60% dry solids
• High nutrient content (dry values)
• Organic C 15.3%
• Nitrogen 3.3%
• Phosphorus 2.9%
• Calcium 17.9%
USDA/NASS 2012 Census; Ohio State University Extension—ANR-4-98
wattagnet.com
labexkorea.wordpress.com

5. Ammonia Emissions
• 16-21 g NH3 year-1 hen-1 from belt
manure systems with forced air
systems producing less
• 13 ppm NH3 from house
exhaust
• 116 g NH3 year-1 hen-1 from
compost of manure
• 123-167 ppm NH3 compost
exhaust
worldpoultry.net
xrpoultry.com
Fournel et al, 2012; Zhao et al, 2008; Ni et al., 2012 (image)

6. Concerns with Poultry AD
Photo: Jim Jensen

7. High Solids Content and Ammonia
• Singh et al., (2010) in their review paper
summarize that poultry manure digestion
without co-digestion is only feasible at TS
< 6% and even then prone to upset and
failure due to ammonia toxicity
• Ward (2003) concluded that of all
treatment options for poultry manure, only
pellets and compost were economically
viable, ruling out AD as non-viable due to
ammonia toxicity, dilution concerns and
non-nutrient resolution
• Recent papers have emphasized
ammonia stripping prior to digestion so as
to resolve most if not all of the AD
concerns (Singh et al., 2010).Gamble, unpublished data

8. Example
Photo: Jim Jensen

9. Ohio Egg Layer AD Example

10. Ohio Egg Layer AD Example

11. Ohio Egg Layer AD Example
Stored manure solids (30-50% total solids) are transported to be mixed with
return water from the digestion and nutrient recovery process. The mixing
process produces an influent of about 9% total solids and a flow rate of about
500 tons day-1 with an ammonia concentration of about 2,500-3,000 mg N L-1.
A nearly closed-loop is developed with 85% of effluent recycled back to the
front end of the system—the missing 15% of effluent is lost during drying and
is replaced with egg wash water.

12. Ohio Egg Layer AD Example
The influent is digested in an approximate 25 day residence anaerobic
digester operating at 100F. Biogas produced from the process is sent to an
engine/generator set to produce electricity to the grid and recovered waste
heat which is used to maintain digester temperature and dry solids.

13. Ohio Egg Layer AD Example
Effluent, not at ammonia concentrations of 3,800-4,000 mg N L-1 is then sent to
an ammonia stripping system to recover the ammonia as gas and then contact
with sulfuric acid to make ammonium sulfate fertilizer for sales. Resulting
ammonia concentrations after treatment are approximately 1,500 mg N L-1

14. Ohio Egg Layer AD Example
After the ammonia is recovered, the remaining effluent is sent to a dissolved air
flotation (DAF) system for removal of fine solids and phosphorus. The system
produces a wastewater that is 2.5% total solids and has 85% of the phosphorus
removed. Product flows from the nutrient recovery are:
• ~ 1.2 tons of ammonia is recovered day-1, to produce roughly 15 tons of
ammonium sulfate solution (8% nitrogen) or upon drying 5-6 tons of
ammonium sulfate solids day-1 (21% N, 24% S)
• ~ 23 tons of dry nutrient solids day-1 with nutrient values of (21% C, 4% N, 6%
P, 1% K, 10% Calcium, 3% Magnesium + other micronutrients)

15. Conclusion
Photo: Jim Jensen

16. Conclusion
• Presently seven poultry digester operations exist on farms in the US, many of
them practicing direct anaerobic digestion of poultry manure and/or off-farm
substrates in a dilute manner to avoid ammonia toxicity.
• Numerous citations in literature as well as emerging commercial systems
endeavor to make a larger bio-refinery around the poultry digestion concept,
incorporating advance ammonia and solids recovery so as to avoid inhibition
and reduce volume of wastewater produced.
• Existing refinement in choice and performance of technologies used in the
systems is on-going as is market maturity for developed fertilizers and
techno-economics for overall viability of such projects.
• Given enhancements and continued demonstration, poultry manure digestion
for combined production of biogas (electricity or CNG) and fertilizer with a
near closed-loop use of waste liquids holds strong potential.
• This potential is now just being realized with several such poultry projects
being pitched in the Chesapeake Region

17. This research was supported by funding from USDA
National Institute of Food and Agriculture, Contract #2012-
6800219814; and from the WSU Agricultural Research
Center;
Acknowledgements

18. Contact Information
Craig Frear, PhD
Assistant Professor
Washington State University
PO Box 646120
Pullman WA 99164-6120
509-335-0194
cfrear@wsu.edu