removing phosphorus from drainage water the phosphorus removal structure

Removing Phosphorus from Drainage Water:

The P Removal Structure

C. Penn, J. Payne*, J. Vitale, J. McGrath and D. Haak

Oklahoma State UniversityUniversity of Maryland

Illinois River Watershed Partnership

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

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Coale, F.J. and R. Kratochvil 2011: Unpublished data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

Phosphorus Sorption Materials

Acid mine drainage residuals

Steel slag

Drinking water treatment residuals

Fly ash

Waste recycled gypsum

Photo Credit: K.D. Chamberlain

Manufactured PSM

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

P P P P P P P P P

High P water

PSM layer

Drainage layerClean water is released

P P PP P P

P P P

3 Necessary Components

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

Advantages of P removal structure

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

Potential application of PSM

Ag runoff

Urban runoff

Many Types of Structures

Confined Bed

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

Box Filter

Perforated steel box Vertically positioned

pipe inside box Filled with steel slag Small ditches or

pond overflow Drawback: small

amount of material

Tile Drained Filter

PSM over and under perforated pipes

Dam at end for slow retention time

Can use large amount of material

Low cost

Storm Drainage Filter

DESIGN GUIDANCE

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

Pilot scale filter at OSU

010203040506070

0 100 200 300

P re

mo

ved

(mg

/kg

)

P added (mg/kg)

Aug 2012Nov 2009

Model use

Site hydrology Targeted P removal PSM characterization

Inputs

Outputs

Design parameters

Example of Software

Example Pond Filter Data

0 20 40 60 80 100 120 140 160 180 2000

10

20

30

40

50

60

70

Measured

Predicted

P added (mg kg-1)

Cum

ulat

ive

P r

emov

ed (

mg

kg-

1)

EXAMPLE DESIGN

Poultry Farm in OK

Creek

flowdirection

poultry houses

structure location

Funding Source: USDA-NRCS CIG

Site Conditions

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

Step by step description found at: www.P-structure.blogspot.com

40 tons treated slag

To date: 67% of dissolved P trapped

0 10 20 30 40 50 60 70 80 90 1000

100

200

300

400

500

600

700

Time (minutes)

Flow

(gal

lons

per

min

ute)

Storm: June 25, 2014

Peak Flow of 687 gpmInflow range 2.25-11.3 mg of P per literRemoved 0.33lb of the 0.58lb P that entered

PSMMass (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 3.60.03 (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

Potential design options to meet given P removal and 1,000 gpm flow

Next steps?

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

Potential uses

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

Thank you!

Illinois River in Oklahoma

Questions

Why did the chicken cross the stream?

To avoid creating a water quality violation!

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

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

ECONOMICS

“IT DEPENDS”

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

Economics Example: Westville

Year $ P removal (lbs.)

Cumulative P removal cost

($/lb P)

1 4989 22 226.772 1213 22 140.953 1213 22 112.354 1213 22 98.055 1213 22 89.466 1213 22 83.747 1213 22 79.66