Designing Structures to Remove Phosphorus from Drainage Waters

C. Penn, J. Payne*, J. McGrath and J. VitaleOklahoma State University

University of Maryland

P transport to surface waters

Occurs primarily via surface flow:

- Particulate P – carried on eroded particles, not immediately bio-available

- Dissolved P – 100% biologically available

P loss to surface water

Soil test P

Potential for P loss

Low Optimum High

Risk increases as soil P increases

Nutrient Sensitive Watersheds

Chesapeake Bay

Illinois River Watershed

Both have:

- High density poultry production

- Urban development

- Limited cropland

- Water quality concerns

Legacy P

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 20100

100

200

300

400

500

600

Trt 1

Trt 2

Trt 3

Trt 4

Trt 5

Coale, F.J. and R. Kratochvil 2011: Unpublished data

Meh

lich-

3 P

hosp

horu

s (m

g kg

-1)

Plant optimum soil test P level

Cessation of fertilizer applications

Managing P Losses

Most traditional BMPs do:- target particulate P

- veg buffers, riparian areas- prevent soil P from increasing

- limit P applications

Managing P losses

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)

Ru

no

ff P

(p

pm

)

P sorbing materials (PSM)

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

One tool: P removal structure

PSM layer with retained P

Low P water

Drainage layer (sand/perforated pipe)

High P water

Examples of waste product PSM’s

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

Selection Process for PSMs

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

Hydraulicconductivity

Advantages of P removal structure

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

Potential application of PSM

Ag runoff

Urban runoff

Pilot scale filter at OSU

010203040506070

0 100 200 300

P re

mo

ved

(mg

/kg

)

P added (mg/kg)

Aug 2012Nov 2009

P removal structure – Golf course

Golf course runoff filter

Overflow weir

25% overall dissolved P removal after 8 months

Structure has handled flow rates over 100 gpm

Steel slag

Cost will vary per site

Cost: $2000 for steel and welder time

Slag was free (3 tons sieved)

$200 to sieve and transport slag

$2,200 total

Stormwater Pond Filter

Perforated steel box Vertically positioned

pipe inside box Filled with steel slag Drains from poultry

farm stormwater pond

Cartridge Ditch Filter

Portable, easy to install

Filled with slag Limited amount of

PSM

Tile Drained Filter

PSM over and under perforated pipes

Gypsum and slag Dam at end for slow

retention time

Tile Drained Filter

After re-vegetation

Model development

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

Model use

Site hydrology Targeted P removal PSM characterization

Inputs

Outputs

Design parameters

Model vs. Actual P removal

P added (mg kg-1)

P r

emo

ved

(m

g k

g-1)

Moving to implementation

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

TMDLs and Nutrient Trading:

P Sources

Illinois River Watershed Chesapeake Bay

NRCS Conservation Innovation Grant

Creek

flowdirection

poultry houses

proposed structure location

Awarded to Illinois River Watershed Partnership and OSU

Will be installed on poultry operation in Illinois River Watershed

Thank you!

Illinois River in Oklahoma