Proceedings available at: http://www.extension.org/67669 Several groups have developed P removal structures, which are units filled with P sorbing materials and designed to channel runoff water through them while retaining the filter material and P. The goal is to prevent P from entering a surface water body and allow filtered P to be removed from the watershed after the P-saturated material is removed. The P sorbing materials utilized are typically by-products from various industries and include steel slag, FGD gypsum, drinking water treatment residuals, and acid mine drainage residuals. A modeling tool has been developed for (1) sizing a structure based on filter media properties and watershed characteristics, (2) predicting the lifetime of a P removal structure, and (3) estimating total P removal. In addition to the modeling tool, data from full scale filters will be presented.

1. C. Penn, J. Payne*, J. McGrath and J. Vitale
Oklahoma State University
University of Maryland

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

3. Soil test P
Potential
for P loss
Low Optimum High
Risk increases as soil P increases

4.  Chesapeake Bay
 Illinois River Watershed
 Both have:
- High density poultry production
- Urban development
- Limited cropland
- Water quality concerns

5. 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Coale, F.J. and R. Kratochvil 2011: Unpublished data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

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

7.  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)

8.  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

9. PSM layer with
retained P
Low P water
Drainage layer
(sand/perforated pipe)
High P water

10. Acid mine
drainage
treatment
residuals
Bauxite
mining and
production
waste (red
mud)
Steel slag
waste
Drinking
water
treatment
residuals
Fly ash
Waste
recycled
gypsum
Foundry Sand

11. 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

12.  Remove both particulate and dissolved P
 Ability to remove PSM after saturation
 Various metals and pesticides are removed
 Target treatment in “hot spots”
 Potential to capture P from entire catchment

13. Ag runoff
Urban runoff

14. 0
10
20
30
40
50
60
70
0 100 200 300
Premoved(mg/kg)
P added (mg/kg)
Aug 2012
Nov 2009

16. Overflow weir
25% overall dissolved P
removal after 8 months
Structure has handled
flow rates over 100 gpm
Steel slag

17.  Cost: $2000 for steel
and welder time
 Slag was free
(3 tons sieved)
 $200 to sieve and
transport slag
 $2,200 total

18.  Perforated steel box
 Vertically positioned
pipe inside box
 Filled with steel slag
 Drains from poultry
farm stormwater pond

19.  Portable, easy to install
 Filled with slag
 Limited amount of
PSM

20.  PSM over and under
perforated pipes
 Gypsum and slag
 Dam at end for slow
retention time

21. After re-vegetation

22.  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

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

24. P added (mg kg-1)
Premoved(mgkg-1)

25.  Possible interest in commercializing design
 Golf course industry
 Ag industry
 Potential NRCS cost share technology
 Nutrient credit brokers

26. Illinois River Watershed Chesapeake Bay

27. Creek
flow
direction
poultry houses
proposed
structure
location
Awarded to Illinois
River Watershed
Partnership and OSU
Will be installed on
poultry operation in
Illinois River Watershed

28. Illinois River in Oklahoma