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.
Removing phosphorus from drainage water the phosphorus removal structure
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Coale, F.J. and R. Kratochvil 2011: Unpublished data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
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
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
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
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
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
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
Soils built up with legacy P will continue to release it for several years.
Corn with different amounts of P.
Plant optimum soil test P level is 32.5 mg/kg in OK. Varies in other states. 50-100 mg/kg in Maryland.
Solution P is a very small part of the total soil P, but is the P fraction taken up by plants; and, if carried in runoff water, may result in immediate stimulation of aquatic growth. Labile soil P is more plentiful than soluble P, but is still only a small fraction of total soil P. Labile P is not strongly adsorbed in the soil and may enter the soluble phase relatively quickly. Lastly, stable, or non-labile, P is in forms unavailable to plants and constitutes the greatest fraction of total soil P. With time, a small amount of non-labile P reacts chemically to become labile P and soluble P. Most non-labile P will remain in the non-labile form indefinitely.
Reducing runoff and trapping sediment P
PSM: any material that chemically removes dissolved P from a solution, reducing soluble P. Examples inlcude Al, Fe, Ca Mg, etc.
PSM can be added to soil or manure to decrease soluble P concentrations; however, it is temporary. You are not removing P from system.
Sorption occurs from adsorption and precipitation. Ca/Mg remove P by precipitation reactions that occur much slower. Al/Fe remove P by adsorption which occurs rapidly.
Precipitation: Ca/Mg must be dissolved into solution where they will then re-precipitate with P in solution to create a new solid.
Adsorption: Adhesion of dissolved solids to a surface.
AMDRs: this is a by-product from treating/neutralizing acid mine drainage waters (such as from tar creek or coal mines). The result is a by-product rich in Fe and Al oxides.
Manufactured PSMs are more common in areas without much industry, particularly in Europe.
Bauxite waste is from Al making industry. Mostly in New Zealand and Australia. Rich in Fe and Al oxides.
Steel slag waste is from making steel. Available everywhere there is a steel mill.
Drinking WTRs are from the process of removing sediment from drinking water. This is highly available all over the US.
Waste gypsum comes from the wall board industry and mostly from the power production industry.
Paper mill waste is rich in Al oxides.
Foundry sand: comes from metal casting industry
Fly ash: Coal fired powered plant
NOT ALL OF THE MATERIALS WILL BE SAFE; THEY NEED TO BE SCREENED PRIOR TO USE particularly for soluble metals
Sieve out fines
AMDRs: this is a by-product from treating acid mine drainage (such as from tar creek or coal mines). The result is a by-product rich in Fe and Al oxides.
Bauxite waste is from Al making industry. Mostly in New Zealand and Australia. Rich in Fe and Al oxides.
Steel slag waste is from making steel. Available everywhere there is a steel mill. Rich in Ca. pH may be high but ability to change pH is low.
Drinking WTRs are from the process of removing sediment from drinking water. This is highly available all over the US.
Waste gypsum comes from the wall board industry and mostly from the power production industry (coal).
Paper mill waste is rich in Al oxides.
NOT ALL OF THE MATERIALS WILL BE SAFE; THEY NEED TO BE SCREENED PRIOR TO USE
Fe and Al – adsorption
Ca – precipitation
Think of it as P filter. Like a Brita filter.
lots of sediment also removed
lots of sediment also removed
Ag runoff pic
3 tons electric arc furnace (EAF) slag treats 150 acres
9 inches of slag
123x76x76 perforated steel box
10.2 cm pipe positioned vertically inside box- radial flow to discharge.
Holds ~1.4 Mg of ¼ slag.
4 boxes in series to discharge.
Drains 2 ha from poultry production area.
Currently monitoring performance with different size fractions of steel slag
Dam at end to back water up and force water to go thru 4 drainage pipes. Pipes have gypsum and slag.
50 Mg < FGD Gypsum
PSM over and under perforated pipes
PSM can be removed and land applied after filter failure
Slow retention time
Works well with base flow (slow rate, low concentration)
Ideal for typical field ditch applications
Structure is developed by observed relationship among experimental data.
How much P it will remove based on inflow P concentrations and retention time.
Different slag with different size fractions. Differences in Ca, alkalinity and pH.
Site hydrology: Peak flow rate, annual flow volume, dissolved P level
Targeted P removal. Targeted lifetime.
PSM characterization: P sorption, safety, physical properties
Design parameters: area, mass depth
Site hydrology: Peak flow rate, annual flow volume, dissolved P level
Targeted P removal. Targeted lifetime.
PSM characterization: P sorption, safety, physical properties
Design parameters: area, mass depth
Model vs structure
Cumulative P removal around 60-70%. 1 storm removed .66 lbs of dissolved P at flow rate of 500 gal/min or 1 cubic ft/sec.
Cumulative P removal around 60-70%. 1 storm removed .66 lbs of dissolved P at flow rate of 500 gal/min or 1 cubic ft/sec.
1 megagram = 1.1 tons
40 m2 = 430 ft2
Input on slope and hydraulic conductivity and it gives mass, area, depth, etc.