http://www.extension.org/67702 Land application of manure in regions with intense confined livestock and poultry production is an environmental concern when land is limiting because it promotes soil phosphorus (P) surplus and potential pollution of water resources. A net accumulation of soil P results from the disproportion between lower nitrogen (N) and P ratio (N:P) in animal manure and the higher N:P ratio in harvested crops. Although manure can be moved off the farm, its transportation becomes less economical with increasing distances from the source. Thus, management alternatives to land application are needed to resolve agronomic P imbalances for more effective recycling of manure P.

1. Process for Recovery of Phosphorus
from Solid Manure
Ariel Szogi, Matias Vanotti, Patrick Hunt
USDA-ARS, Coastal Plain Soil, Water,& Plant
Research Center
Florence, SC

2. Overview
• Why phosphorus recovery?
• What did we do?
• What we have learned?
• Future plans

3. Environmental Issues
• N:P ratio - Animal Waste vs. Crop Plants
• Accumulation of manure P in soil
• Limited mineral phosphate reserves
Why phosphorus recovery?

4. N:P Ratio & Soil P Accumulation
Manure N:P = 2:1
Nutrient Uptake
Plant N:P > 4.0
Soil P surplus Runoff
Leaching

5. Recoverable Manure P
• Quantity of the nutrient available for land application or utilization for other
purposes
• Mass of nutrient per ton of manure remaining after nutrient losses during
manure collection, transfer, storage, and treatment
• Total U.S. annual production of recoverable P2O5 = 650,000 Mt
Source: USDA-NRCS (Kellogg et al. 2000)
18%
17%
8%
19%
38%
Cattle
Dairy
Other
Swine
Poultry

6. ARS-Quick
Wash Process
Phosphorus
Recovery Process
Washed
Solid Residue
Selective
P extraction
Manure
Solids
P precipitation
P precipitation
enhancement
Recovered P
Liquid
1
2
3
U.S. Patent Pending
Licensed by
Renewable Nutrients LLC
Pinehurst, NC
What did we do?

7. Animal Waste
High in Phosphorus
Washed
Solid
Residue
STEP 2
Lime
Dewatered
Concentrated
Phosphorus
Solids
Decanted Liquid
+ Soluble
Phosphorus
Effluent
STEP 3
Flocculant
Dewatered
Low P
Manure
Solids
STEP 1
Acid
D
D
Quick Wash Process

8. Quick Wash Pilot Treatment Unit

9. Quick Wash – Poultry Litter
• Step 1: Acidification: pH 3 – 5
Mineral or organic acids (e.g. sulfuric, hydrochloric, citric,
oxalic, EDTA)
• Step 2: P precipitation: Liming
pH 10 with hydrated lime (calcium hydroxide)
• Step 3: P precipitation enhancement
Anionic polymer (PAM)

10. Quick Wash - Poultry Litter
• Washed solid residue
Low P product – Step 1
• Recovered Phosphorus
Concentrated P – Steps 2&3

11. Quick Wash – Poultry Litter
Step 1 – P Selective Extraction
pH 8.1 pH 4.5

12. Quick Wash – Poultry Litter
Step 1 – P Selective Extraction
pH 8.1 pH 4.5

13. Quick Wash – Poultry Litter
Step 1 – P Selective Extraction
pH 8.1 pH 4.5
Control Treatment
N:P 1.8:1 5.8:1

14. Quick Wash – Poultry Litter
Step 2 & 3 – P Recovery
Lime addition
0
200
400
600
800
0 2 4 6 8 10 12 14
pH
TotalPinLiquidExtract
(mg/L)
0
20
40
60
80
100
TotalPRemovedfrom
LiquidExtract(%)

15. P removal
Lime addition
pH 9 - 10
P enhancement
Flocculant addition
(PAM -)
Quick Wash – Poultry Litter
Pilot Unit
Step 2 Step 3

16. Phosphorus Concentration
Dry Weight Basis
Source Total P P2O5
% %
Raw broiler litter 2.0 4.6
Recovered broiler litter 5.9 13.5

17. Elemental Composition of Recovered
P Material from Poultry Litter
Constituent Mean
%
Phosphorus 5.9*
Calcium 13.4
Carbon 23.8
Nitrogen 2.4
Magnesium 1.0
Potassium 1.1
Sodium 0.3
*Recovered P material > 90% plant
available P (citrate-soluble)

18. Quick Wash – Tested Applications
• Poultry waste: Broiler and Turkey litter,
Laying hen manure
• Animal waste: Swine manure
• Municipal biosolids

19. Use of Recovered P as Fertilizer
Greenhouse Study
•Annual ryegrass
•P Sources: 1) recovered P,
2) raw broiler litter,
3) TSP
4) unfertilized - control
•Soil with very low content of plant
available P

20. Use of Recovered P as Fertilizer
RESULTS:
• There was significant dry matter production for all P sources with respect
to a unfertilized control
• Differences in dry matter production were not significant
among P sources except at very high application rates of commercial TSP
The recovered P is suited for its use as a source of P fertilizer
Greenhouse Study
•Annual ryegrass
•P Sources: 1) recovered P,
2) raw broiler litter,
3) TSP
4) unfertilized - control
•Soil with very low content of plant
available P

21. Challenges & Opportunities
• Increasing price of fertilizers
• Policies on manure management
• Incentives to adopt new technology
• Treatment costs (manure type, % P
removal target, equipment)

22. Opportunities
• Recovery of P from manure can help to reduce manure
P application to soils already high in P.
• The aspect of P recovery and reuse is important for the
global cycling of P. Unlike N, world reserves of high
quality mineral P are limited.
• Centralized treatment facilities have been proposed to
recover P in areas with high density of animal
production
• Potential economic benefits from water quality credits
programs

23. Publications
• Szogi, A.A., Vanotti, M.B., and Hunt, P.G. Phosphorus recovery from
poultry litter. Trans. ASABE 51(5):1727-1734. 2008.
• Szogi, A.A., and Vanotti, M.B. Prospects for phosphorus recovery from
poultry litter. Bioresour. Technol. 100(22):5461-5465. 2009.
• Szogi, A.A., Bauer, P.J., and Vanotti, M.B. Fertilizer effectiveness of
phosphorus recovered from broiler litter. Agron. J. 102(2):723-727. 2010.
• Szogi, A.A., Bauer, P.J., and Vanotti, M.B. Vertical distribution of
phosphorus in a sandy soil fertilized with recovered manure phosphates. J.
Soils Sediments 12(3):334-340. 2012.