Maximizing Phosphorus Load Reduction
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www.ContechES.com Maximizing Phosphorus Load Reduction Presented By: Derek M. Berg Southeast New York Stormwater Conference October 15, 2014
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Transcript of Maximizing Phosphorus Load Reduction
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Maximizing Phosphorus Load Reduction
Presented By: Derek M. Berg
Southeast New York Stormwater Conference
October 15, 2014
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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
and innovation
Agenda
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Why do we care about Phosphorus?
Aren’t nutrients a good thing? Phosphorus is usually the most limiting nutrient
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◦ Dissolved P◦ Ortho P◦ Soluble Reactive P
TP is most commonly regulated
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Lake Productivity Classification
Total Phosphorus mg/L
Ultra-oligotrophic <5
Oligotrophic 5-10
Mesotrophic 10-30
Eutrophic 30-100
Hypereutrophic >100
Phosphorus in Lakes
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
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How do we address TP in runoff?
• Good Housekeeping • Runoff Reduction• Sedimentation• Biofiltration• Media Filtration
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Source Washington State Water Quality Consortium
(Not So) Good House Keeping
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Preventing runoff from occurring or reaching receiving waters eliminates all of the pollutants that would be carried by that runoff
Reduce runoff via LID site design concepts Retain water onsite
o RWHo Bioretentiono Pervious paverso Infiltration Systems
Runoff Reduction
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Removing Phosphorus With Treatment
Three primary mechanisms to removal Phosphorus from Urban runoff:
Reactive FiltrationPhysical FiltrationSedimentation
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SedimentationExamples: 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/ ProcessesReactive 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)
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SandFilter (Sedimentation, Physical Filtration)
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Bioretention/Biofiltration
Source: NYSDEC Chap. 5 NYS Stormwater Management Design Manual
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Raising the Bar on TP Removal With Innovative 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
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Results: TDP Removal Efficiency
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)
0
10
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Control Sorbtive Media 5% Sorbtive Media 10%
% T
DP
Rem
ova
l
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Lakewood Park - Chautauqua Lake
Retrofit DI’s• Sorbtive Media applied
in a layer above underdrain pipe
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Filterra® Bioretention
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Optimized media gradation Functions as living biological system Simple Maintenance Consistent field removal of >60% TP Can be deployed boxless
Filterra Overview
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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
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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
Fleming College
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NYSDEC 80% TSS, 40% TP threshold is essentially pass fail Currently no review process in place to assign specific TP
credit to BMPs Limited value in achieving >40% TP without means of taking
regulatory credit In load sensitive watersheds
Regulatory Challenges
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Summary
