Phosphorus Treatment – Advanced Removal

Mechanisms & Amended Design for Stormwater BMPs

Scott Perry, CPSWQ

Nov. 17th, 2011

OverviewOverview Phosphorus BasicsPhosphorus Basics

NPS LoadsNPS Loads

Stormwater BMP Stormwater BMP

performanceperformance

Ways to Increase Ways to Increase

Phosphorus RemovalPhosphorus Removal

Advanced Removal MechanismAdvanced Removal Mechanism

Amended BMP DesignsAmended BMP Designs

Things to AvoidThings to Avoid

Phosphorus BasicsPhosphorus Basics Essential nutrient for lifeEssential nutrient for life

Cyclic between land & waterCyclic between land & water

Limiting nutrient in freshwaterLimiting nutrient in freshwater

Millions of Years

Canadian Canadian Experimental Experimental Lakes Area # Lakes Area #

226:226: Plastic Curtain Plastic Curtain

divides lakedivides lake

Carbon & Nitrogen Carbon & Nitrogen

added to both sidesadded to both sides

Phosphorus added Phosphorus added

to lower halfto lower halfFisheries and Oceans Canada - 1973

Phosphorus added

Lake Erie – Sept. 2008

Lake Erie – Sept. 2009

Lake Erie - Oct. 2010

Problem: Excess Phosphorus in fresh water Excess Phosphorus in fresh water

causes causes EutrophicationEutrophication (over (over enrichment):enrichment):

Algal bloomsAlgal blooms Micro-toxins … Micro-toxins … Cyanobacteria

HypoxiaHypoxiaFish killsFish kills Invasive speciesInvasive species

Lake ChamplainAP & VPR News - 2010

Additional Issues :

Taste & odor problems Fish & aquatic community Recreational quality Property values Drinking Water Cost

Charles River – Boston Metro

FertilizersFertilizers Animal & Pet WasteAnimal & Pet Waste Vegetation & Leaves Vegetation & Leaves DetergentsDetergents Erosion & Sediment LossErosion & Sediment Loss Hydrocarbons & LubricantsHydrocarbons & Lubricants Airborne Fallout: Dust, Pollen, Fossil Airborne Fallout: Dust, Pollen, Fossil

FuelsFuels Waste Water (CSO / Septic)Waste Water (CSO / Septic)

NPS Phosphorus NPS Phosphorus

SourcesSources

Chesapeake Bay Chesapeake Bay Pollen Load from Pollen Load from Outfalls APR09Outfalls APR09

Turf --- fertilizer and Turf --- fertilizer and

compacted soils/lawnscompacted soils/lawns

Chesapeake Bay WatershedChesapeake Bay Watershed

Relative Responsibility for Pollution Loads to the bayRelative Responsibility for Pollution Loads to the bay

NitrogenNitrogen PhosphorusPhosphorus SedimentSediment

Charles River WatershedCharles River Watershed

Phosphorus Stormwater Phosphorus Stormwater Loading by Land Use Loading by Land Use

0

0.5

1

1.5

Pounds

/ Acre

/ Y

ear

EPA Stormwater BMP Design Guide, 2004

Imperviousness Cover &Phosphorus Load

Center for Watershed Protection - Schueler and Caraco 2001

USGS Water-Resources Investigations Report 99–4021

Tota

l Ph

osp

horu

s (m

g/L

)

% Tree Canopy

Phosphorus Load with Increasing % Tree Canopy

USGS Water-Resources Investigations Report 99–4021

Tota

l Ph

osp

horu

s (m

g/L

)

% Tree Canopy

Roadway Phosphorus EMC with Increasing % Tree Canopy

Total Phosphorus (TP) Total Phosphorus (TP) PartitioningPartitioning

1. Particulate-Bound (PB) Phosphorus

2. Dissolved Phosphorus (DP)

Bio-availableBio-available

““QUICK SUGAR”QUICK SUGAR” for Algal Blooms for Algal Blooms

Sediment particle

Phosphorus Partitioning Phosphorus Partitioning by Land Useby Land Use

Residential Commercial Industrial Open Space

Ave. TP EMC (mg/L) 0.41 0.34 0.45 0.59

Ave. DP EMC (mg/L) 0.20 0.18 0.16 0.16

% PB 51 % 47 % 64 % 73 %

% DP 49 % 53 % 36 % 27 %

National Stormwater Quality Database

New York State DEC, 2008

TP = Particulate-bound phosphorus & Dissolved Phosphorus

DP = Dissolved Phosphorus

PB = Particulate-bound Phosphorus

Phosphorus in Phosphorus in StormwaterStormwater

TSS

+

50% TP --- Associated with TSS (sediment)

50% TP --- Dissolved (< 0.45-mircons)

Typical Urban Stormwater BMPs designed to captures 80% TSS:

80% TSS capture X 50% (particulate-bound phosphorus) = 40% (TP) Removal

Particulate-bound

Phosphorus (PB)

Sediment particle

Dissolved Phosphorus

(DP)

or

Range of Total Phosphorus (TP)

% Removal per BMP Type

Center for Watershed Protection,

National Pollutant Performance Removal Database version3, Sept. 2007

-100

-80

-60

-40

-20

0

20

40

60

80

100

Dry

Po

nd

s

We

t P

on

ds

We

tla

nd

Fil

teri

ng

Pra

cti

ce

s

Bio

rete

nti

on

Infi

ltra

tio

nP

rac

tic

es

Op

en

Ch

an

ne

ls

% R

emo

val E

ffic

ien

cy

Factors impacting Factors impacting Phosphorus Fate & Phosphorus Fate &

TransportTransport Water chemistry conditionsWater chemistry conditions

pHpH AlkalinityAlkalinity Temperature / SeasonalityTemperature / Seasonality Redox potentialRedox potential Particle chargeParticle charge ConcentrationConcentration

Time / Maintenance frequencyTime / Maintenance frequency

Phosphorus FatePhosphorus Fate Phosphorus speciation will shiftPhosphorus speciation will shift

ExamplesExamples Runoff pH

Concrete Road > 7.0 vs Asphalt < 5.0 Bottom of Lakes

Anaerobic activity / decaying organics

Stormwater TP Removal Stormwater TP Removal Mechanisms & Generalized Mechanisms & Generalized

CapabilityCapabilityUnit Process /

Removal Mechanism

Total Phosphorus (TP)

Sedimentation

Yes No

Filtration Yes Limited

Biological Uptake

Limited*assuming vegetative harvesting

Limited*assuming vegetative harvesting

Sorption No Yes

SorptioSorptio

nn

Adsorption Absorption

Combination of physiochemical Combination of physiochemical interactions;interactions; Adsorption - surface attachment Adsorption - surface attachment Absorption - internal attachment (sponge)Absorption - internal attachment (sponge) Ion Exchange - displacement of ions (Ca, Mg, Ion Exchange - displacement of ions (Ca, Mg,

Na)Na)

Sorption Capacity --- mg/g

Compared to soils … Ion Exchange Capacity --- meq/100g

Methods to Methods to Increase Increase

TP removal & TP removal & reduce variationreduce variation

Sediment particle

1 - Increase TSS Removal1 - Increase TSS Removal

Achieve > 80% TSS Removal

A. Remove the most particulate-bound phosphorus

• Silt-sized particles (Filtration)

(63-microns)

B. Prevent ResuspensionSediment particle

Particulate-Bound Particulate-Bound PhosphorusPhosphorus

TSS

Silt & Clay

Prevent or mitigate anaerobic Prevent or mitigate anaerobic conditionsconditions

Maintenance (removal of decaying Maintenance (removal of decaying materials)materials)

CatchbasinsCatchbasins ForebaysForebays WetlandsWetlands Underground SystemsUnderground Systems

2 - Mitigate Phosphorus 2 - Mitigate Phosphorus Speciation ShiftSpeciation Shift

Green InfrastructureGreen Infrastructure

Reduce Impervious Cover and/or ImpactReduce Impervious Cover and/or Impact Maximize InfiltrationMaximize Infiltration Maximize EvapotranspirationMaximize Evapotranspiration Combine Technology with Green Combine Technology with Green

InfrastructureInfrastructure

3 - Runoff Reduction --- 3 - Runoff Reduction --- i.e. Infiltrationi.e. Infiltration

Range of Total Phosphorus (TP)

% Removal per BMP Type

Center for Watershed Protection,

National Pollutant Performance Removal Database version3, Sept. 2007

-100

-80

-60

-40

-20

0

20

40

60

80

100

Dry

Po

nd

s

We

t P

on

ds

We

tla

nd

Fil

teri

ng

Pra

cti

ce

s

Bio

rete

nti

on

Infi

ltra

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nP

rac

tic

es

Op

en

Ch

an

ne

ls

% R

emo

val E

ffic

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cy

Advanced Removal Advanced Removal MechanismsMechanisms

4 - Target ALL Phosphorus 4 - Target ALL Phosphorus (i.e. ... The Dissolved Phase (i.e. ... The Dissolved Phase

too)too)

Particulate boundParticulate bound

Sediment particle

Dissolved Phosphorus

Advanced Removal Advanced Removal MechanismsMechanisms

Practices that do not Infiltrate 100%

Engineer to Capture Dissolved Engineer to Capture Dissolved PhosphorusPhosphorus

Amend & DesignAmend & Design Engineered MediaEngineered Media

Displace conventional media or Displace conventional media or aggregateaggregate

Polish exfiltrating systemsPolish exfiltrating systems

Quantifying Engineered Quantifying Engineered MediaMedia

Isotherm – Isotherm – Best Case Maximum capacity?

Kinetics – Kinetics – How fast can it be sorbed?

Breakthrough –Breakthrough – Volume of Pollutant/WQv treated?

(maintenance)

Desorption – Desorption – Retaining DP … is the bond strong enough?

Influent

Effluent

What is Breakthrough?What is Breakthrough?Phosphorus Breakthrough Curve

Thomas Equation

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 500 1000 1500 2000 2500 3000 3500

Number of Bed Volumes

% D

isso

lved

Ph

osp

ho

rus

Rem

ova

l

Dissolved Phosphorus Sorption Performance (T. Wu et al, Stormwater Phosphorus Adsorption on Oxide Coated Media, WEFTEC,2008)

Media Type(0.5 mm to 10 mm)

IsothermKf (mg/g)

Kineticsqe (mg/g)

Breakthrough Exhaustion

(BVs)

Desorption

Al-oxide Pumice 0.40 1.19 1,800 – 2,700 No

Al-oxide Aggregate 1.3 0.51 1,450 – 3,600 No

Zeolite / Perlite / Carbon (ZPG)

0.05 None 5 Yes

Perlite 0.002 1.37 < 10 No

Recycled Tire 0.003 None < 45 Yes

Expanded Shale 0.14 0.98 9 - 50 Yes

Very Finely Graded Medias (< 0.5 mm) with low hydraulic conductivity

Bioretention Soil 0.18 4.67 50 No

Concrete Sand < 0.01 < 0.001 < 5 No

Amended Amended Low Impact DevelopmentLow Impact Development

Surface Filters that ExfiltrateSurface Filters that Exfiltrate

ApplicationsApplications

Sorption based Media

Amended Surface FiltersAmended Surface Filters

(sand filters / bioretention)(sand filters / bioretention)

ApplicationsApplications

Sorption based Media

Amended Pervious PavementsAmended Pervious Pavements

ApplicationsApplications

Under Drain PVC

Sorption based Media

Green Roof ResearchGreen Roof Research

7-inches of growth media

Previous Research Previous Research Observed:Observed:

Runoff ReductionRunoff Reduction Increased Phosphorus Increased Phosphorus

DischargeDischarge

Green Roof ResearchGreen Roof Research Previous Research Previous Research

Observed:Observed: Runoff ReductionRunoff Reduction Increased Phosphorus Increased Phosphorus

DischargeDischarge

Greenroof Study Greenroof Study FindingsFindings

2009 Runoff Reduction = 42%2009 Runoff Reduction = 42% 2010 Runoff Reduction = 53%2010 Runoff Reduction = 53%

August - 77% versus October - 15%August - 77% versus October - 15%

NET EXPORTER of PhosphorusNET EXPORTER of Phosphorus TP discharged:TP discharged: ≈ ≈ 2 mg/L to 2 mg/L to ≈≈ 0.6 mg/L 0.6 mg/L

Engineered Media … Exfiltration Treatment:Engineered Media … Exfiltration Treatment: TP Reduction (87%): TP Reduction (87%): 1.18 to 0.16 mg/L1.18 to 0.16 mg/L SRP Reduction (82%): 0.63 to 0.11 mg/L 0.63 to 0.11 mg/L

Things to Avoid with Things to Avoid with “Sorption” Materials “Sorption” Materials

Things to Avoid with “Sorption” Things to Avoid with “Sorption” Materials Materials

Monitor the use of materials prone Monitor the use of materials prone to to desorptiondesorption

Organics / Compost / SoilsOrganics / Compost / Soils Evaluate MaterialEvaluate Material

Prevent Prevent leachingleaching of other Toxics of other Toxics pH, Heavy MetalspH, Heavy Metals

Slag, waste by-products

Things to Avoid with Things to Avoid with “Sorption” Materials “Sorption” Materials

Leaches Phosphoru

s

Summary Summary

Urban Runoff is a significant Urban Runoff is a significant Phosphorus contributorPhosphorus contributor

Infiltration should be the first Infiltration should be the first tool to combattool to combat

Exfiltration should treat Exfiltration should treat Dissolved PhosphorusDissolved Phosphorus (DP) (DP) with an Engineered Media with an Engineered Media

Scott Perry

301-279-8827

sperry@imbriumsystems.com

Questions?

AP/Larry Dupont – Lake Champlain