This presentation explores the issue of phosphorus in stormwater runoff, including what it is, where it comes from, and common phosphorous treatment practices.

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Maximizing Phosphorus Load
Reduction
Presented By: Derek M. Berg
Southeast New York Stormwater Conference
October 15, 2014

2.  Phosphorus: What is it and where does it come from?
 How do we address Phosphorus in Urban Runoff?
 Raising the bar on phosphorus removal the latest research
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and innovation
Agenda

3. Why do we care about Phosphorus?
 Aren’t nutrients a good thing?
 Phosphorus is usually the most limiting nutrient
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in freshwater systems
 Too much of a good things makes watersheds
sick

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Sources of Phosphorus
 Weathering of calcium phosphate minerals,
especially apatite
 Anthropogenic (human) P is often much greater
than natural inputs of P in many watersheds
 Common anthropogenic sources: agriculture,
wastewater, excess fertilizer, faulty septic
 Wildlife can also contribute significant amounts
of phosphorus to local watersheds

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Forms of Phosphorus
 Total P: Is most common measure of phosphorus
concentrations in runoff and watersheds. TP = DIP + DOP +
PP
 We often measure both particulate and dissolved fractions of
phosphorus
o Dissolved P
o Ortho P
o Soluble Reactive P
 TP is most commonly regulated

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Phosphorus in Lakes
Lake Productivity
Classification
Total Phosphorus mg/L
Ultra-oligotrophic <5
Oligotrophic 5-10
Mesotrophic 10-30
Eutrophic 30-100
Hypereutrophic >100
Phosphorus concentrations in untreated stormwater are often many times
higher than those in receiving waters!

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Phosphorus in Stormwater
• Phosphorus is often in both solid and soluble forms
• Solid phosphorus tends to be associated with finer particles
• Ratio of solid/soluble is often variable. Research suggests
50/50 split is a reasonable estimate (NYSDEC Chap. 10)
• Previously captured particulate can be leached as soluble P

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Phosphorus in Stormwater
Source: NYSDEC Chap. 10 NYS Stormwater Management Design Manual

9. How do we address TP in runoff?
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• Good Housekeeping
• Runoff Reduction
• Sedimentation
• Biofiltration
• Media Filtration

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(Not So) Good House Keeping
Source Washington State Water Quality Consortium

11. Runoff Reduction
 Preventing runoff from occurring or reaching receiving waters
eliminates all of the pollutants that would be carried by that
runoff
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 Reduce runoff via LID site design concepts
 Retain water onsite
o RWH
o Bioretention
o Pervious pavers
o Infiltration Systems

12. Removing Phosphorus With Treatment
Three primary mechanisms to removal Phosphorus from Urban
runoff:
Sedimentation Physical Filtration Reactive Filtration
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Sedimentation
Examples: Ponds, Vaults, Detention Systems, Hydrodynamic Separators
• Slow water down and allow solids to
settle
• Longer residence time = finer particles
captured
• Phosphorus removal often tied to
residence time
• No capture of dissolved/soluble P
• Leaching possible

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Physical Filtration
Examples: Screening, Media Filters, Sand Filters, Biofilters, Infiltration
• Physical barrier to solid particles
• Good control of TSS and attached
pollutants
• Good removal of particulate metals
and phosphorus
• No removal of dissolved/soluble
pollutants
• Leaching possible
• Longevity must be considered

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Maximizing TP Removal

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Reactive Filtration/ Processes
Reactive filtration media with an affinity for target pollutants,
organic matter,
• Often works in parallel with physical
filtration and/or sedimentation
• Target pollutant is bound to media via
adsorption, ion exchange etc.
• Effective removal of soluble/dissolved
pollutants
• Boosts overall pollutant load reduction
• Prevents leaching

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Common Treatment Practices

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Wet Pond (Sedimentation)

19. SandFilter (Sedimentation, Physical Filtration)
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Bioretention/Biofiltration
Source: NYSDEC Chap. 5 NYS Stormwater Management Design Manual

21. Raising the Bar on TP Removal With Innovative
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Solutions

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Case Study 4
Bioretention Soil Amendment
Fleming College, Ontario

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Bioretention Soil Mix Amendment
with Phosphorus-Adsorbing Sorbtive Media
Fleming College, Centre for Alternative
Wastewater Treatment
Ontario, Canada
Case Study 3

24. Results: TDP Removal Efficiency
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100
90
80
70
60
50
40
30
20
10
0
TDPs Influent Conc
(0.2 mg/L)
TDPs Influent Conc
(0.4 mg/L)
TDPs Influent Conc
(0.6 mg/L)
TDPs Influent Conc
(0.8 mg/L)
% TDP Removal
Control Sorbtive Media 5% Sorbtive Media 10%

25. Lakewood Park - Chautauqua Lake
Retrofit DI’s
• Sorbtive Media applied
in a layer above
underdrain pipe
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2
Filterra® Bioretention

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Filterra Overview
 Optimized media gradation
 Functions as living biological system
 Simple Maintenance
 Consistent field removal of >60% TP
 Can be deployed boxless

28. The Stormwater Management StormFilter®
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PhosphoSorb Media
 Lightweight, oxide coated, non
toxic, reactive media
 Lab testing showed excellent
removal of dissolved P
 TAPE and TARP field testing
showing >70% TP reduction
and excellent removal of DP

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Solids Removal- SOL

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Phosphorus Removal- SOL

32. Fleming College
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Soil Mix Composition
 Sand
 Peat Moss
 Sorbtive® Media AI 28x48
• High surface area phosphorus-adsorbing media
• Sand-like gradation
• Added to soil mix on volume basis, ranging 0% - 17%
 Soil components mixed in buckets of 2 front-end loaders

33. Regulatory Challenges
 NYSDEC 80% TSS, 40% TP threshold is essentially pass fail
 Currently no review process in place to assign specific TP
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credit to BMPs
 Limited value in achieving >40% TP without means of taking
regulatory credit
 In load sensitive watersheds

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Summary

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Questions???
Derek Berg
dberg@conteches.com
207-885-6174