Phosphorus Treatment – Advanced Removal Mechanisms & Amended Design for Stormwater BMPs Scott Perry, CPSWQ Nov. 17 th, 2011

Overview Phosphorus Basics Phosphorus Basics NPS Loads NPS Loads Stormwater BMP performance Stormwater BMP performance Ways to Increase Phosphorus Removal Ways to Increase Phosphorus Removal Advanced Removal Mechanism Advanced Removal Mechanism Amended BMP Designs Amended BMP Designs Things to Avoid Things to Avoid

Phosphorus Basics Essential nutrient for life Essential nutrient for life Cyclic between land & water Cyclic between land & water Limiting nutrient in freshwater Limiting nutrient in freshwater

Millions of Years

Canadian Experimental Lakes Area # 226: Plastic Curtain divides lake Plastic Curtain divides lake Carbon & Nitrogen added to both sides Carbon & Nitrogen added to both sides Phosphorus added to lower half Phosphorus added to lower half Fisheries and Oceans Canada Phosphorus added

Lake Erie – Sept Lake Erie – Sept Lake Erie - Oct. 2010

Problem: Excess Phosphorus in fresh water causes Eutrophication (over enrichment): Excess Phosphorus in fresh water causes Eutrophication (over enrichment): Algal blooms Algal blooms Micro-toxins … Micro-toxins … Cyanobacteria Hypoxia Hypoxia Fish kills Fish kills Invasive species Invasive species Lake Champlain AP & VPR News

Additional Issues : Taste & odor problems Fish & aquatic community Recreational quality Property values Drinking Water Cost Charles River – Boston Metro

Fertilizers Fertilizers Animal & Pet Waste Animal & Pet Waste Vegetation & Leaves Vegetation & Leaves Detergents Detergents Erosion & Sediment Loss Erosion & Sediment Loss Hydrocarbons & Lubricants Hydrocarbons & Lubricants Airborne Fallout: Dust, Pollen, Fossil Fuels Airborne Fallout: Dust, Pollen, Fossil Fuels Waste Water (CSO / Septic) Waste Water (CSO / Septic) NPS Phosphorus Sources

Chesapeake Bay Pollen Load from Outfalls APR09

Turf --- fertilizer and compacted soils/lawns

Chesapeake Bay Watershed Relative Responsibility for Pollution Loads to the bay Nitrogen Phosphoru s Sediment

Charles River Watershed

Phosphorus Stormwater Loading by Land Use 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 Total Phosphorus (mg/L) % Tree Canopy Phosphorus Load with Increasing % Tree Canopy

USGS Water-Resources Investigations Report 99–4021 Total Phosphorus (mg/L) % Tree Canopy Roadway Phosphorus EMC with Increasing % Tree Canopy

Total Phosphorus Load with Increasing % Tree Canopy Green Streets / City Tree Canopy

Total Phosphorus (TP) Partitioning Particulate-Bound (PB) Phosphorus Dissolved Phosphorus (DP) Bio-available Bio-available “QUICK SUGAR” for Algal Blooms “QUICK SUGAR” for Algal Blooms Sediment particle

Phosphorus Partitioning by Land Use ResidentialCommercialIndustrialOpen Space Ave. TP EMC (mg/L) Ave. DP EMC (mg/L) % PB51 %47 %64 %73 % % DP49 %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 Stormwater 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

Factors impacting Phosphorus Fate & Transport Water chemistry conditions Water chemistry conditions pH pH Alkalinity Alkalinity Temperature / Seasonality Temperature / Seasonality Redox potential Redox potential Particle charge Particle charge Concentration Concentration Time / Maintenance frequency Time / Maintenance frequency

Phosphorus Fate Phosphorus speciation will shift Phosphorus speciation will shift Examples Examples Runoff pH Concrete Road > 7.0 vs Asphalt < 5.0 Bottom of Lakes Anaerobic activity / decaying organics

Stormwater TP Removal Mechanisms & Generalized Capability Unit Process / Removal Mechanism Total Phosphorus (TP) Sedimentation YesNo Filtration YesLimited Biological Uptake Limited *assuming vegetative harvesting Limited *assuming vegetative harvesting Sorption NoYes

Sorption Adsorption Absorption Combination of physiochemical interactions; Combination of physiochemical interactions; Adsorption - surface attachment Adsorption - surface attachment Absorption - internal attachment (sponge) Absorption - internal attachment (sponge) Ion Exchange - displacement of ions (Ca, Mg, Na) Ion Exchange - displacement of ions (Ca, Mg, Na) Sorption Capacity --- mg/g Compared to soils … Ion Exchange Capacity --- meq/100g

Methods to Increase TP removal & reduce variation Sediment particle

1 - Increase TSS Removal Achieve > 80% TSS Removal A. A. Remove the most particulate-bound phosphorus Silt-sized particles (Filtration) (63-microns) B. B. Prevent Resuspension Sediment particle

Particulate-Bound Phosphorus TSS Silt & Clay

Prevent or mitigate anaerobic conditions Prevent or mitigate anaerobic conditions Maintenance (removal of decaying materials) Maintenance (removal of decaying materials) Catchbasins Catchbasins Forebays Forebays Wetlands Wetlands Underground Systems Underground Systems 2 - Mitigate Phosphorus Speciation Shift

Green Infrastructure Reduce Impervious Cover and/or Impact Reduce Impervious Cover and/or Impact Maximize Infiltration Maximize Infiltration Maximize Evapotranspiration Maximize Evapotranspiration Combine Technology with Green Infrastructure Combine Technology with Green Infrastructure 3 - Runoff Reduction --- i.e. Infiltration

Range of Total Phosphorus (TP) % Removal per BMP Type Center for Watershed Protection, National Pollutant Performance Removal Database version3, Sept. 2007

Hot Spots Hot Spots Pretreatment prior to Infiltration? Pretreatment prior to Infiltration? Urban Area may not be conducive Urban Area may not be conducive Cost ($) of Land Cost ($) of Land Soils may not be suitable Soils may not be suitable Maintenance !!! Maintenance !!! Green Infrastructure Other Considerations

Green Infrastructure Design Considerations

Advanced Removal Mechanisms

4 - Target ALL Phosphorus (i.e.... The Dissolved Phase too) Particulate bound Sediment particle Dissolved Phosphorus

Advanced Removal Mechanisms Practices that do not Infiltrate 100% Engineer to Capture Dissolved Phosphorus Engineer to Capture Dissolved Phosphorus Amend & Design Amend & Design Engineered Media Engineered Media Displace conventional media or aggregate Displace conventional media or aggregate Polish exfiltrating systems Polish exfiltrating systems

Quantifying Engineered Media 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?

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) Isotherm K f (mg/g) Kinetics q e (mg/g) Breakthrough Exhaustion (BVs) Desorption Al-oxide Pumice ,800 – 2,700No Al-oxide Aggregate ,450 – 3,600No Zeolite / Perlite / Carbon (ZPG) 0.05None 5Yes Perlite < 10No Recycled Tire 0.003None < 45Yes Expanded Shale Yes Very Finely Graded Medias (< 0.5 mm) with low hydraulic conductivity Bioretention Soil No Concrete Sand < 0.01< < 5No

Amended Low Impact Development Surface Filters that Exfiltrate Applications Sorption based Media

Amended Surface Filters (sand filters / bioretention) Applications Sorption based Media

Amended Pervious Pavements Applications Under Drain PVC Sorption based Media

Green Roof Research 7-inches of growth media Previous Research Observed: Previous Research Observed: Runoff Reduction Runoff Reduction Increased Phosphorus Discharge Increased Phosphorus Discharge

Green Roof Research Previous Research Observed: Previous Research Observed: Runoff Reduction Runoff Reduction Increased Phosphorus Discharge Increased Phosphorus Discharge

Greenroof Study Findings 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 Phosphorus NET EXPORTER of Phosphorus TP discharged:≈ 2 mg/L to ≈ 0.6 mg/L TP discharged:≈ 2 mg/L to ≈ 0.6 mg/L Engineered Media … Exfiltration Treatment: Engineered Media … Exfiltration Treatment: TP Reduction (87%): 1.18 to 0.16 mg/L TP Reduction (87%): 1.18 to 0.16 mg/L 0.63 to 0.11 mg/L SRP Reduction (82%): 0.63 to 0.11 mg/L

Things to Avoid with “Sorption” Materials

Monitor the use of materials prone to desorption Monitor the use of materials prone to desorption Organics / Compost / Soils Organics / Compost / Soils Evaluate Material Evaluate Material Prevent leaching of other Toxics Prevent leaching of other Toxics pH, Heavy Metals pH, Heavy Metals Slag, waste by-products

Things to Avoid with “Sorption” Materials Leaches Phosphorus

Summary Urban Runoff is a significant Phosphorus contributor Urban Runoff is a significant Phosphorus contributor Infiltration should be the first tool to combat Infiltration should be the first tool to combat Exfiltration should treat Dissolved Phosphorus (DP) with an Engineered Media Exfiltration should treat Dissolved Phosphorus (DP) with an Engineered Media

Scott Perry Questions? AP/Larry Dupont – Lake Champlain