Effective BMPs for Controlling Copper and Zinc - … BMPs for Controlling Copper and Zinc ... Temperature pH Dissolved Organic Carbon Calcium Magnesium ... Zinc Copper USGS 4th field

Effective BMPs for Controlling

Copper and ZincACWA Stormwater Summit 2016

Aaron Poresky and Myles Gray,

Geosyntec Consultants

Outline

• Metals in stormwater

• Regulatory setting and trends

• BMP selection and

effectiveness

• Case studies and scientific

trends

Copper and Zinc Are Challenging to Control

• They are hazardous to aquatic

organisms (including salmon)

• They are ubiquitous

• They exhibit complicated

chemistry

• They are subject to tightening

environmental standards

• Achieving compliance can be

costly and complicated

BUT… BMPs can work and they can work better

Copper is Ubiquitous• Brake Pads (4-12%)

• Construction Materials (including

pressure treated wood)

• Pesticides & Fungicides

• Aerial Deposition

Land Use Total Copper (µg/L)1 Dissolved Copper (µg/L) 1

Commercial 15 (13-17) 6 (5-9)

Freeway 24 (21-29) 11 (9-12)

Industrial 16 (14-19) 8 (6-10)

Residential 11 (10-12) 5 (3-7)

Open Space 5 (5-7) --

1Total and Dissolved copper median values with 95% confidence intervalsSource: National Stormwater Quality Database

Washington Dept of Ecology Study2:

• Cars emit ~0.6 mg Cu/km

• 36,000 kg emitted in Puget Sound Region

• Copper Loading: 200-500 g Cu/km-yr

• Equivalent to App. 16 µg/L from highway

2Source: Washington Dept of Ecology, 2011, “Copper and Zinc Loading Associated with Automotive Brake-Pad and Tire Wear”

Commercial Industrial Open Space Residential

Source: Seattle Public Utilities Integrated Plan, Appendix F

6

Copper: Characteristics in Stormwater

Particulate-bound Copper

Particles retained on 0.45 micron

filter

“Dissolved” Copper

Free (or ionic) copper

Complexed Copper (e.g., CuDOM)

Colloidal copper (particles passing 0.45 micron filter)

Cu2+

Sorbed to clay

~50% <5%

Complexed with EDTA (i.e. Dissolved Organic Matter)

Combined 45-50%

7

Copper is Harmful to Aquatic Organisms

-BUT- Toxicity depends on Water Chemistry

EPA Biotic Ligand Model (BLM)

• Model to estimate free ions on gills

BLM Factors:

Temperature

pH

Dissolved Organic Carbon

Calcium

Magnesium

Sodium

Potassium

Sulfate

Chloride

Alkalinity

Humic Acid

Zinc is Even More Widespread!

• Tire Dust (~1% Zinc)

• Galvanized Metals

• Motor Oil

• Moss-Off

• Aerial Deposition

Land Use Total Zinc (µg/L)1 Dissolved Zinc (µg/L) 1

Commercial 130 (114-143) 56 (42-70)

Freeway 132 (120-162) 51 (42-62)

Industrial 155 (140-170) 114 (59-180)

Residential 70 (69-77) 27 (25-33)

Open Space 25 (25-25) 25 (25-25)

1Total and Dissolved zinc median values with 95% confidence intervalsSource: National Stormwater Quality Database

Washington Ecology Study2:

• Cars emit ~1.13 mg Cu/km

• 79,000 kg emitted in Puget Sound Region

• Copper Loading: 700-1,200 g Cu/km-yr

• Equivalent to App. 33 µg/L from highway

Zinc-Based Moss Off:

• $6.98 per 1.3 kg can

• 468 g Zinc/can

• Recommended use would

create rooftop effluent

with 66,000 µ/L during 1”

rainfall event

2Source: Washington Dept of Ecology, 2011, “Copper and Zinc Loading Associated with Automotive Brake-Pad and Tire Wear”

Commercial Industrial Open Space Residential

Source: Seattle Public Utilities Integrated Plan, Appendix F

10

Zinc: Characteristics and Toxicity

• Depending on sources, greater fraction “ionic”

• Less affinity for organic ligands = less toxic than copper

Particulate-bound Zinc

Particles retained on 0.45 micron

filter

“Dissolved” Zinc

Free (or ionic) ZincComplexed Zinc

(e.g., Zn-Carbonate)

Colloidal Zinc (particles passing 0.45 micron filter)

Zn2+

Regulatory Setting - Metals

Phase I MS4 Permits

– MEP and BMP-based, 80% capture sizing

standards, LID/GI approaches

– In-stream and stormwater monitoring

– Review of SWMPs for effectiveness in

addressing 303(d) listed pollutants

– Various provisions for TMDL pollutants

1200-Z Industrial Permit

– Copper: 20 ppb

– Zinc: 120 ppb

– MS4 permits require screening and

inspections

– Portland, Eugene, and CWS administer

programs on behalf of DEQ

SLOPES V Transportation, Utilities

Source control and treatment BMP-based, but larger design storm

Project-specific NMFS Biological Opinion – Example - Walmart, The Dalles, OR

5 ppb total copper, never to exceed, monitoring first flush after extended dry period, no mixing

zone allowance

0 20 40 60 80 100 120 140 160 180

Coast Fork WillametteLower ColumbiaLower John DayLower Owyhee

Lower WillametteMiddle Columbia-Hood

Middle WillametteNorth UmpquaSouth Umpqua

TualatinUmatillaUmpqua

Upper WillametteWallowa

Yamhill

2012 draft 303(d) listStream Miles in Category 5: TMDL Needed

Zinc

Copper

USGS 4th field HUC

Data from Oregon DEQ 2012 Draft Integrated Report

DEQ Copper Rulemaking

• Updates to criteria will

replace hardness-based

criteria

• EPA 2007 recommendations

include deriving criteria from

Biotic Ligand Model (BLM)

• DEQ developed BLM

technical support document

(Jan 2016)

1Source: Oregon DEQ 2016, “Technical Support Document: An Evaluation to Derive Statewide Copper Criteria Using the Biotic Ligand Model. Figure from Santore, 2015 and Pagenkopf, 1983

BLM Conceptual Model1

Source: Oregon DEQ 2016, “Technical Support Document: An Evaluation to Derive Statewide Copper Criteria Using the Biotic Ligand Model.

1Source: Oregon DEQ 2016, “Technical Support Document: An Evaluation to Derive Statewide Copper Criteria Using the Biotic Ligand Model.

Regulatory Summary

• More stringent BMP performance criteria

are likely to emerge

– WQ criteria rulemaking 303(d)/TMDL

process NPDES permits

– NMFS consultations/biological opinions/

SLOPES

Overall Framework for BMP Effectiveness

BMP

Bypass or Overflow

Volume Loss (Infiltration, ET,

Direct Use)

Combined Discharge

Treated Effluent

Influent

Source Controls

and Site DesignStructural BMPs

Site-specific criteria and

flow/WQ conditions

How effective is “effective enough”?

Reduce load and change chemistry

Source Control: First Option

Legislative:

Restrict use of high

metals materials

Washington and

California bans on

copper brakepads

Others: Zinc Moss-Off?

Material Selection:

Avoid specific materials:

• Galvanized Metals

• Copper Building

Materials

• Pressure-treated

Wood

• Copper-based Paints

• Copper-based

pesticides

Operations:

General good

housekeeping

Spill Cleanup

Street Sweeping (high

efficiency regenerative

vacuum)

Paint/Coat Galvanized

Materials

Site Design / LID / Green Infrastructure

• Impervious area dispersion

• Natural drainage pathways/swales

• Riparian buffer protection

• Soil and organic matter play multiple roles:

– Load reduction

– DOC source

– Buffering capacity

– Speciation change

1Source: Oregon Low Impact Development Overview Fact Sheet 2016. oeconline.org/stormwaterhttp://extension.oregonstate.edu/watershed/

Treatment BMP Effectiveness

BMP

Bypass or Overflow

Volume Loss (Infiltration, ET,

Direct Use)

Combined Discharge

Treated Effluent

Influent

• How much is captured and treated?

• How much is “lost” and not discharged to surface water?

• Is the change in concentrations significant?

• What is the effluent concentration?

Copper and Zinc Treatment MechanismsSpeciation/Partition Mechanism(s) BMP Types

Coarse Particulates Screening, Rapid Settling, and Swirling

Forebays, Hydrodynamic Separators

Medium TSS-range Particulates SettlingVegetative Entrapment

Ponds, Wetlands, Swales, Filters

Fine TSS-range Particulates Media FiltrationExtended SettlingCoagulation

Passive and Active Filtration BMPsWetlands

Ionic Ion Exchange (e.g., zeolite) Passive and Active Filtration BMPsWetlands/Bioreactors

Organically Complexed Physical Sorption (e.g., GAC)Biological uptake

Passive and Active Filtration BMPsWetlands/Bioreactors

Ionic, inorganically complexed Chemical Sorption & Precipitation Passive and Active Filtration BMPsWetlands/Bioreactors

www.bmpdatabase.org

22

BMP Study Types in International

BMP Database

BMP Category #Bioretention 43Composite 26

Detention Basin 43Green Roof 17Biofilter 89

Infiltration Basin 2LID 4

Manufactured Device 103Media Filter 40

Maintenance Practice 29Other 6

Porous Pavement 41

Percolation Trench/Well 13Retention Pond 77Wetland Basin 35

Wetland Channel 19Total BMPs 587Control Sites 2223

• 17 general BMP categories

• 190 to 240 plus Green

Infrastructure BMP Studies

www.bmpdatabase.org

1200Z

BLM avg(Will. Valley)

Source: Geosyntec Consultants and Wright Water Engineers, 2014. “International Stormwater BMP Database Pollutant Category Statistical Summary Report”

BMP Effectiveness for Total Copper

Source: Geosyntec Consultants and Wright Water Engineers, 2014. “International Stormwater BMP Database Pollutant Category Statistical Summary Report

0

10

20

30

40

0 10 20 30 40

Eff

luent D

Cu (mg/L

)

Influent DCu (mg/L)

All Data Pairs: N=89

In=Out

Bootstrap Medians: Span=13 R2=0.677

95% Confidence Interval

Vegetated Swales – Dissolved Copper

Source: Geosyntec Consultants. Unpublished analysis of International Stormwater BMP Database data; roving window median bootstrap analysis

0

5

10

15

20

25

0 5 10 15 20 25

Eff

lue

nt D

Cu

(mg

/L)

Influent DCu (mg/L)


In=Out



Extended Detention Basins – Dissolved Copper




Wet Ponds – Dissolved Copper

0

5

10

15

20

25

30

35

40

45

0 5 10 15 20 25 30 35 40 45

Eff

luent D

Cu (mg/L

)

Influent DCu (mg/L)


In=Out




1200Z

Hardness-based at 40 ppm


BMP Effectiveness for Total Zinc


Vegetated Swales – Dissolved Zinc

0

50

100

150

200

250

0 20 40 60 80 100 120 140 160 180 200 220 240

Eff

lue

nt D

Zn

(m

g/L

)

Influent DZn (mg/L)


In=Out




Extended Detention Basins – Dissolved Zinc

0

20

40

60

80

100

120

140

160

180

200

0 20 40 60 80 100 120 140 160 180 200

Eff

luent D

Zn (m

g/L

)

Influent DZn (mg/L)


In=Out






0

20

40

60

80

100

120

0 20 40 60 80 100 120

Eff

luent D

Zn (m

g/L

)

Influent DZn (mg/L)


In=Out



Wet Ponds – Dissolved Zinc


Proprietary and Active BMPs

Passive Media Filters:TAPE Certified for Enhanced Dissolved Metals1:

• Filterra

• Modular Wetlands

• WSDOT Media Filter Drain

• WSDOT Compost Amended BiofiltrationSwale

• Others with conditional use

Criteria:

• 30 percent removal of DCu (at influent of 5 to 20 ppb)

• 60 percent removal of DZn (at influent of 20 to 300 ppb)

Active Treatment Technologies:

Electrocoagulation: WaterTectonics, EnPurion

Chitosan Treatment

Active Media Filters: EnPurion, StormwateRx

Chemical Treatment

WaterTectonics2

2Source: www.WaterTectonics.com

1Source: Washington Department of Ecology TAPE Website: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/technologies.html

BMP Effectiveness Summary - Copper

• BMPs are generally effective for particulate-bound Cu, with appropriate unit processes

• Most BMPs have little effect on dissolved Cu, except:

– Specialized media

– Redoxic conditions and/or very long residence times (i.e., wetlands)

• Performance variability is high and ranges often overlap with WQ criteria

• Some BMPs can be a source (some bioretention)

• Recent research is showing that some BMPs can reduce toxic effects without reducing load

• Achievability needs to be considered in translating WQ criteria to BMP performance standards

BMP Effectiveness Summary - Zinc

• Most conventional BMPs address total and

dissolved Zn

• Some sources can still be hard to treat (e.g.,

galvanized roofs); focus on source controls

needed

• Achievability is a particularly consideration for low

hardness receiving waters

Case Studies: How can we do better?

• Reducing the irreducible concentration

• Improving consistency in effluent quality

• Maximizing volume reduction where

feasible and desirable

• Increasing system longevity

Case Study – SEATAC Airport• Stormwater discharges for the airport are regulated under an

individual industrial stormwater permit

• Project objective: Redesign and construct media filter beds to

comply with increasingly stringent permit limits for:

– Copper (hardness-based)

– Zinc (hardness-based)

• Comply with existing permit limits for:

– Turbidity

– Oil & Grease

– pH

• Team: Port of Seattle, RW Beck, and Geosyntec

SEATAC Retrofit Options

• Improve system hydraulics

– Improve residence time for smaller, more frequent storms

– Reduce potential for short circuiting

– Reduce pore velocities and potential for washout of fines

• Incorporate “designer” media components targeted to

pollutants/species

– Sorption

– Cation exchange

Media and Hydraulic Recommendations

for SEATAC Retrofits

Planting Mix < 25% well-aged compost

Treatment Mix50% rhyolite30% zeolite

20% GAC

Pea gravel bridging layer

Drain rock

12”

12”

2-4”

SEATAC Biofilter Monitoring Results

Storm DateStorm Depth,

inches TCu Influent, ug/L TCu Effluent, ug/L7/20/2012 0.57 35.3 4.6

10/12/2012 0.24 84.7 7.811/12/2012 0.72 8.9 2.511/29/2012 1.59 15.3 3.9

1/9/2013 1.51 6.5 2.12/6/2013 Not available 12.3 1.9

Average Influent

Average Effluent

TSS (mg/L) 12.6 2.2

Total Copper (ug/L) 27.2 3.8

Dissolved Copper (ug/L) 14.5 3.4

Total Zinc (ug/L) 63.7 11.8

Dissolved Zinc (ug/L) 46.3 10.8

Hardness (mg-CaCO3/L) 13.6 44.8

Total Copper by Storm Event

Source: SDS1 Bioretention Swale Performance Evaluation Report, Prepared for Port of Seattle by CardnoTEC. January 2104.

What is Biochar?Biochar = Bio-Energy ByProduct

• Nearly any Biomass Feedstock

• Different Production Conditions

Resists Decay = Sequesters Carbon

Unique Physical & Chemical Properties

= valuable filtration media

Image Source: Lehmann et al. 2007. “A handful of carbon”

Highly Porous; Surface Area up to 500 m2/g

Multiple pore sizes: from nm to mm range

Highly stable carbon structure with sorption

sites on edges

Sorption capacity increases over time

Biochar Properties and Metal Removal

Biochar = Green alternative to Activated Carbon

Biochar Design Considerations

Hazelnut Shell Douglas-Fir Cane Pith

Biochar is not created equal treatability testing

Raw Biochar Contains Fine Particles = Hydraulic Problems and Leaching

Raw Biochar Must be rinsed or sieved

Port of Port Townsend OverviewComprehensive Biochar Feasibility Study

Treatability Testing Pilot Testing Installation and Monitoring

Biochar Sourced from Neighboring Paper Mill• Rinsed, Screened, and Blended

Field Testing of 20 upflow filters and 2 in-ground filters• Upflow filter rated for ~20 GPM• In-Ground filters rated for ~150 GPM

Port of Port Townsend ResultsDownspout Filters Removal:

Mean Influent Mean EffluentMean

Removal

ug/L ug/L %

Total Copper 54.2 7.88 71.1%

Total Zinc 1018 39.0 92.6%

In-Ground Filters Removal:

Mean Influent Mean EffluentMean

Removal

ug/L ug/L %

Total Copper 2419 1336 52.6%

Total Zinc 1078 366 52.9%

Overall, Results Indicated:

• Excellent removal with downspout filters

• Variable removal with in-ground filters

• Media rinsing is critical to improve flow rates and contaminant removal and to prevent leaching of fine particles

• Port Townsend biochar can cause a short-term nutrient pulse, especially unrinsed

Source: Gray et al. 2015. “Port of Port Townsend Biochar Stormwater Filtration Feasibility Study”

Kitsap County Bioretention SoilIn response to copper and phosphorus export from bioretention soil

Multiple testing rounds to identify better media• Included rinsed biochar, GAC, designer sands, coconut coir• Also included control mix: 60% sand / 40% compost

Image Source: Herrera, Kitsap County, WSU, WSDOT, SPU, Geosyntec. 2015. “Analysis of Bioretention Soil Media for Improved Nitrogen, Phosphorus, and Copper Retention.”

Figure Source: Herrera Environmental Consultants, 2012. “Pollutant Export from Bioretention Soil Mix”

Kitsap County Bioretention Soil Testing

Total Cu

Biochar blends among top performers

Dissolved Cu Total Zn Dissolved Zn

Image Source: Herrera, Kitsap County, WSU, WSDOT, SPU, Geosyntec. 2015. “Analysis of Bioretention Soil Media for Improved Nitrogen, Phosphorus, and Copper Retention.”

Questions?

Aaron Poresky Myles Gray

[email protected] [email protected]

Documents

Effective BMPs for Controlling Copper and Zinc - … BMPs for Controlling Copper and Zinc ... Temperature pH Dissolved Organic Carbon Calcium Magnesium ... Zinc Copper USGS 4th field