Full proceedings available at: http://www.extension.org/72839 We constructed a phosphorus (P) removal structure on a poultry farm in Eastern OK; this is a BMP that can remove dissolved P loading in the short term until soil legacy P concentrations decrease below levels of environmental concern. A P removal structure contains P sorbing materials (PSMs) and are placed in a location to intercept runoff or subsurface drainage with high dissolved P concentrations. As high P water flows through the PSMs, dissolved P is sorbed onto the materials by several potential mechanisms, allowing low P water to exit the structure. While they vary in form, P removal structures contain three main elements: 1) use of a filter material that has a high affinity for P, 2) containment of the material, and 3) the ability to remove that material and replace it after it becomes saturated with P and is no longer effective.

1. C. Penn, J. Payne*, J. Vitale, J. McGrath and D. Haak
Oklahoma State University
University of Maryland
Illinois River Watershed Partnership

2.  Occurs primarily via
surface flow:
- Particulate P – carried
on eroded particles,
not immediately bio-
available
- Dissolved P – 100%
biologically available

3. 0
100
200
300
400
500
600
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
Trt 1
Trt 2
Trt 3
Trt 4
Trt 5
Coale, F.J. and R. Kratochvil 2011: Unpublished data
Mehlich-3Phosphorus(mgkg-1)
Plant optimum soil test P level
Cessation of fertilizer applications

4.  Most traditional BMPs do:
- target particulate P
- veg buffers, riparian areas
- prevent soil P from increasing
- limit P applications

5.  Most traditional BMPs do not:
- target dissolved P
- difficult to target
 High P soils will continue to produce
dissolved P for years
Runoff P vs. Soil Test P (Miami, OK)
y = 0.0016x + 0.287
R2
= 0.89
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 500 1000 1500 2000 2500
Soil Test P (ppm)
RunoffP(ppm)

6.  PSM:
-any material that chemically removes dissolved P
from a solution, reducing soluble P.
 Examples include: Al, Fe, Ca and Mg.
 Many by-products contain P sorbing minerals.
 Can be used for treatment of soil or manure;
however, P is not removed from system.
 Better use would be treatment of runoff

7. Acid mine
drainage
residuals
Steel slag
Drinking
water
treatment
residuals
Fly ash
Waste
recycled
gypsum
Photo Credit: K.D. Chamberlain
Manufactured
PSM

8. Material Availability
Cost & Transportation
Potential contaminants
Alkalinity/acidity
Soluble salts
Total,
acid soluble,
and water soluble
Na & heavy metalsSorption characteristics
Physical Properties
Particle size
distribution
and bulk density
Hydraulic
conductivity

9. High P water
PSM layer
Drainage layerClean water
is released

10.  Effective PSM in sufficient quantity
 P-rich water must flow thru PSM
 Ability to retain and replace PSM

11.  Remove both particulate and dissolved P
 Ability to remove PSM after saturation
 Various metals and pesticides are removed

12. Ag runoff
Urban runoff

15. Confined Bed
• Good for large filter
• Ideal for drainage
swales that require
high peak flow and
non restricted
drainage
– Achieved through
shallow PSM with
large surface area

16.  Perforated steel box
 Vertically positioned
pipe inside box
 Filled with steel slag
 Small ditches or pond
overflow
 Drawback: small
amount of material

17.  PSM over and under
perforated pipes
 Dam at end for slow
retention time
 Can use large amount
of material
 Low cost

19. DESIGN GUIDANCE

20.  Developed with lab flow through studies and
validated with pilot scale filter
 Developed a user friendly empirical model
 Tested 16 different materials
- add P at constant rate
- vary retention time and P concentration
- measure P in outflow

21. 0
10
20
30
40
50
60
70
0 100 200 300
Premoved(mg/kg)
P added (mg/kg)
Aug 2012
Nov 2009

22. Site hydrology Targeted P removal PSM characterization
Inputs
Outputs
Design parameters

24. 0
10
20
30
40
50
60
70
0 50 100 150 200
CumulativePremoved(mgkg-1)
P added (mg kg-1)
Measured
Predicted

25. EXAMPLE DESIGN

26. Creek
flow
direction
poultry houses
structure
location
Funding Source:
USDA-NRCS CIG

27.  Drainage area: 9 acres
 Slope: 6%
 Peak flow rate; 2 yr, 24 hr storm: 1,000 gpm
 Annual flow volume: 9 acre-ft
 Typical dissolved P: 1 - 2 mg L-1
 Annual dissolved P load: 49 lbs
 Goal is to remove 45% of annual load

30. Step by step description found at:
www.P-structure.blogspot.com
 40 tons treated slag
 To date: 67% of
dissolved P trapped

31. 0
100
200
300
400
500
600
700
0 20 40 60 80 100
Flow(gallonsperminute)
Time (minutes)
Peak Flow of 687 gpm
Inflow range 2.25-11.3 mg of P per liter
Removed 0.33lb of the 0.58lb P that entered

32. PSM
Mass
(Mg)
Cumulative
year 1
removal (%)
Lifetime
(yrs)
Hydraulic
conductivity
(cm s-1)
Area
(m2)
PSM
depth (cm)
WTR* 7 37 21 0.01 286 2.3
AMDR† 4 50 7 0.009 225 2.2
Fly ash‡
3 (plus
95%
sand)
50 3.6
0.03 (mixed
with 95%
sand)
406 13
>6.35 cm slag§ 171 21 1.4 1.0 190 50
Treated > 6.35
cm slag**
36 45 3.5 1.0 40 50

33.  Design software is completed
 Interactive guidance based on user inputs
 OSU is licensing software
 NRCS standard (cost-share) will be completed after
software is online
 Commercialization is key to dissemination

34.  Golf course industry
 Home-owners association
 Storm water management
 Ag industry
 TMDLs
 Nutrient credit brokers

35. Illinois River in Oklahoma

36. Why did the chicken cross the stream?
To avoid creating a water quality violation!

37. Comparison to other BMPs
• In the short term there is no BMP that can
appreciably reduce soluble P losses where
flow cannot be reduced
– P “mining” with hay crops
or corn to reduce soil P
levels
• Sharpley et al. (2009): only
4.6 mg/kg decrease per year
in Mehlich-3 P with
continuous corn
• Not very fast

38. Comparison to other BMPs
• Treatment wetlands
– Require excessive
retention time (days),
thus requires many
acres of space if high
flow rates are to be
treated
• inefficient
– P is not really removed
from the system

39. ECONOMICS
“IT DEPENDS”

40. Economics Example: Westville
• Metal & custom fabrication: $2677
– ¼” carbon steel
• Slag transportation, sieving, coating: $853
• Earth work for pad & berms: $846
• Paint, seed, & erosion mat: $613
• TOTAL: ~ $5000
• Includes profit from private companies
except for metal painting and installation
• Annual renewal estimated at $1213

41. Economics Example: Westville
Year $
P removal
(lbs.)
Cumulative P
removal cost
($/lb P)
1 4989 22 226.77
2 1213 22 140.95
3 1213 22 112.35
4 1213 22 98.05
5 1213 22 89.46
6 1213 22 83.74
7 1213 22 79.66