Nutrient Removal:Costsand Benefits,Degrees of Difficulty, andRegulatory Decision Making

8/10/2019 Nutrient Removal:Costsand Benefits,Degrees of Difficulty, andRegulatory Decision Making

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How to Participate Today

How to participate Audio Modes

Listen using Mic&Speakers

Or, select Use Telephoneand dial the conference

Submit your text questionsusing the Questions pane

A recording will be availablefor replay shortly after thisweb seminar


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Agenda2:00-2:05 Welcome and Introduction

Amit Pramanik, WERF2:05-2:30 Finding the Sustainable Balance on Nutrient

Removal

Michael Falk, HDR, Inc.

2:30-3:10 Research on Characterization and Speciationof N and P

David Stensel, University of Washington

3:10-3:35 Managing Water Quality Translating Research

to PracticeDave Clark, HDR, Inc.

3:35-3:45 Questions and Answers

3:45 Adjourn


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Michael Falk, PhD, PE

Wastewater process engineer at HDR

Engineering

Specializes in nutrient removal and

optimization of wastewater reactors

Ph.D. from UC Davis with an emphasis onthe microbial ecology of activated sludge

This work is part of WERFs Nutrient

Challenge titled Striking a Balance

between Nutrient Removal andSustainability


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Tradeoff Between NutrientRemoval and Sustainability

Michael Falk, PhD; J.B. Neethling, PhD; Dave Reardon, BCEEHDR Engineering, Inc.

Amit Pramanik, PhD, BCEEM

Water Environment Research Foundation


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Acknowledgements

WERF:

Amit Pramanik, PhD, BCEEM

Reviewers:

Kartik Chandran, PhDMichael Stenstrom, PhD, PE, BCEEHDR:

JB Neethl ing, PhD, PE, BCEEDave Reardon, PE, BCEE


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Presentation Outline

Focus/Objectives

Background

Results & Discussion

Potential Impacts toWastewater Plants

Summary & Conclusions


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The Nutrient Storm is aNational Phenomenon

Long Island Sound

DO low in half ofsound

Water quality tradingprogramimplemented

Gulf of Mexico

Large dead zone

Importance ofphosphorus

SacramentoRegional

Concern over

ammonia/nitrateloads in Delta


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Focus/Objectives

Determine sustainability impacts of fivelevels of treatment for 10 mgd plant

Determine if there is a point of

diminishing returns for sustainabilitywith increased treatment


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What is Sustainability?

Energy

Polish YourGreen Image

Greenhouse Gas

Social

Environmental

Stewardship


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Sustainability

Sustainability is Often Described asAchieving the Triple Bottom Line

Water Quality

Greenhouse Gas

Odors/Air Quality

Economics/Life-Cycle Cost

Analysis

Waste Products Consumables

Social/Community

Impacts


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What Did We Consider for theTriple Bottom Line?

Economic Pillar:Total Project Cost

O&M Cost

Environmental Pillar: GHGs (Energy Demand, Chem

manufacturing/hauling, N2O, biosolidshauling)

Water Quality

Ancillary Benefits of IncreasedTreatmentSocial Pillar:

Discussion in WERF Report

Existing metrics (Health)

Future metrics (Social)


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Treatment Level Objectives

LevelBOD

(mg/L)TSS

(mg/L)TN

(mg N/L)TP

(mg P/L)

1 30 30 - -

2


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Level Primary Ferm.

Act Sludge

Relative

Footprint

High

Rate

Clar. Filter MF/RO

Return-

Stream

Treatment

Metal

Salt

(Chem.)

Methanol

(Chem.)

1

1X

2

2X

Optional Opt ional

3

2-2.5X

4

2-2.5X

Denit.

5

2-2.5X

Denit.

a

Treatment Unit Processes

a RO requires brine management (assumed deep well injection)


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System Inputs

(Thicken/Digest/Dewater)

Wastewater

CollectionLiquid Stream

Treatment

Discharge

Plant Boundary

Boundary for this Study

Biological Solids Treatment

GHG

EnergyProduction

GHG

Chem Mining,

Manufacturing,

& Hauling

GHG

GHG

GHGGHG

Solids

Disposal

GHG

Deep Well

Injection

(Level 5)

GHG

Biosolids

Hauling

GHGCogen

GHG

Tertiary Add-On

Disinfection

GHG


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GHG Distribution

-2,000

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000 N2OEmissions (w/Data Range as Bars)

Biosolids Hauling and CH4 Emissions

DeepWell Injection

Aeration

ChemicalsPumping/

Mixing

Miscellaneous

Cogeneration

CO2 eq mt/yr


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Incremental GHG per Additional

lb N or P Removed

3

18 23

338

0.5

16

190

3,400

0

1

10

100

1,000

10,000

Level 1 to 2 Level 2 to 3 Level 3 to 4 Level 4 to 5Incremen

talGHG

Increase

perAdditionallb

NPRemoved(CO2eq

lb/N

orPlb)

Incremental GHG Increase per Change in Treatment Level for N

Incremental GHG Increase per Change in Treatment Level for P


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Potential Algae Production

0

2,500

5,000

7,500

10,000

12,500

15,000

17,500

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

Level 1 Level 2 Level 3 Level 4 Level 5

GHG

Emissions(CO2

eqmttons/yr)

Alg

aeProductionperTreatmentLevel

(lbalga

e/d)

Algae Production GHG Emiss ions


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Ancillary Benefits ofNutrient Removal

Lower BOD and TSS discharge load

Higher removal of micro-constituentsand metals

Water more conditioned for filtration,disinfection, and reuse applications

Fewer algal blooms Greater process stabil ity from the

anaerobic/anoxic zones serving as

selectors


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Whats It Going to Cost Youfor a 10 mgd Plant?

Treatment Level

Total ProjectCosts

($ Million) i

OperationsCost

($/MG) ii

Total PresentWorth

($ Million) ii i

1 (No N/P Removal) 93 250 110

2 (8 mg N/L; 1 mg P/L) 127 350 150

3 (4-8 mg N/L; 0.1-0.3 mg P/L) 144 640 180

4 (3 mg N/L N;


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Summary/Conclusions

1. GHG impacts from all levels of treatment aredominated by energy consumption

2. Levels 4 & 5 may have sustainability impacts thatoutweigh potential water quality improvements

3. Why even discharge Levels 4/5?

4. Capital and operating costs may make Level 4

and 5 treatment difficult to implement withratepayers

5. Use a more holistic approach to watershednutrient management


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Potential Impacts toDischargers

Nutrient wave is coming

Impacts on site constrained plants

(nutrient removal requires MOREspace)

More energy and chemicals Additional operators (more skilled)


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H. David Stensel, PhD, PE, BCEE

Professor of civil and environmental engineering, University

of Washington, Seattle, WA

Principal research activities: biological wastewater

treatment, biological nutrient removal, biodegradation of

micropollutants, anaerobic digestion methods, and water

reuse

ASCE Rudolf Hering Medal, twice received the WEFHarrison Prescott Eddy Medal, and the Water Environment

Bradley Gascoigne Medal for research publications

Registered professional engineer and a diplomat in the American Academy of

Environmental Engineers

B.S. degree in Civil Engineering from Union College in Schenectady, N.Y. andM.E. and Ph.D. degrees in environmental engineering from Cornell University.


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Coconuts and Bananas in BNR Effluents

Research on Characterization and Speciation

of Effluent Nitrogen and Phosphorus

WERF Research

Webinar

October 5, 2011

H. David Stensel, PhD, PE, BCEE

University of Washington

Seattle, WA

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WWTP Effluents are a Source ofNutrients to Surface Waters

Nitrogen (N) and Phosphorus (P) are removedfrom wastewater effluents to limit nutrientenrichment and eutrophication in surface waters

Nutrients enrich streams and lakes to promotehigher algae and plant growth

Eutrophication causes low dissolved oxygen to

harm aquatic life

Chesapeake Bay, Long Island Sound, Gulf ofMexico, many coastal estuaries and fresh water

impoundments are impaired due to nutrients 37


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WWTPs Are Point Source DischargersRegulated for Effluent N and P

Effluent permit concentrations typically based on not toexceed total nitrogen (TN) and/or total phosphorus (TP)concentration

Range of low effluent TN concentration limits

TN 3.0 mg/L common in Chesapeake and Floridacoast

TN 2.0 mg/L or 1.0 mg/L applied in a few cases

Range of low effluent TP concentration limits

0.10 to 0.20 mg/L is becoming more common


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The Dissolved Portion of TN and TP is a

Major Component at Low Effluent Limits

~ 0.01 mg/LpOrg N

DON

NH3-N

~0.81.5 mg/L

~ 0.50 mg/L

NOx-N~ 1.5 mg/L

TN~3.0 mg/L

TP~0.10 mg/L

pP

DP


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The Problem with Trying to Reduce

DON and DP Lower

Biological processes can bepushed to meet low NH4-Nand Nox

DON residual observed

DON can increase withmore aeration time

BNR effluent DON variesfor different WWTPs

Increase chemical dose candrive reactive P to lowerconcentration

But DP is not all reactive P

0

3

6

9

12

15

Primary

effluent

Anaerobic

effluent

Anoxic

effluent

Aerobic

effluent

Concentration,gN/m3

0.45-1.2 m

0.1-0.45 m

< 0.1 m

Example:

DON profile across Gdansk, Poland

BNR WWTP -


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But effluent DON

concentration varies for

different WWTPs

Meeting TN3.0 mg/L

can be possible,unreliable,

or impossible

0.0

0.5

1.0

1.5

2.0

2.5

3.0

.01 .1 1 5 10 2030 50 7080 90 95 99 99.999.99

DON Effluent Concentrations

from 33 BNR Facilities

Percent

DONConc.,mg/L

41


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Chemical Analysis

Total P

Dissolved P (DP)

Filtered

Particulate P (PP)

Reactive Dissolved P(RDP) Non-Reactive Dissolved P(nRDP)

Total Reactive P

(TRP)


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Non-reactive Dissolved P is very

significant in BNR tertiary effluents

with high chemical dose

0%

20%

40%

60%

80%

100%

NDWRFSDWRF MBR Ruidoso CUMF 1st BW 2nd BW TMF MSWTP Z2E

Pcomposition

PP

DOP

SRP

Biological Removal ACTI FiltrationBlue WaterMBR Membrane

nRDP


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C d B P l


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Coconuts and Bananas Postulate

Bo Li University of Washington

Some DON and nRDP is readily available

to algae and some is not

Reactive P (PO4-3)

Amino acids

Inorganic P

Apatite

( Ca3(PO4)2 )

AlPO4 FePO4

.

RecalcitrantsN and P in humic substances

Organic P Polyphosphate

Inositol hexakisphophate

L--phosphatidyl choline

phosphoenol pyruvate

Glycerophosphate .

Bioavailable


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Readily bioavailable


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WERF Nutrient Challenge ProgramEvaluate Bioavailability of Effluent DON and DP

Professor David Sedlak, UC Berkeley

Protocol for Algae Bioassay for effluent DON

Evaluate fraction of recalcitrant DON at BNR WWTPs

Evaluate type of constituents resistant to bioavailability Professor Michael Brett, University of Washington

Protocol for Algae Bioassay for effluent DP

Evaluate fraction recalcitrant P at BNR WWTPs and Tertiary

Treatment with Chemicals

Develop long term bioassay test

Evaluate type of constituents resistant to bioavailability


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Evaluate effect of Tertiary Treatment Processon bioavailable P fraction in effluent

Identify banana

Assess relationship between total reactive P,BAP, and total P

Find a better way to identify banana

Test Bioavailability of P speciesWhich species of banana will be more

tasty?

Or stated another way. . .

Studies Used Bioassay Methods


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Selenastrum capricornutumInitial concentration:10,000 cells/ml

Incubate for 14 days.

Culturing condition:

1.Continuous Illumination

2.Temperature: 24 2C

3. shake at 110 rpm.

Studies Used Bioassay Methods

Cell Counts or Chlorophyll a to

Measure Algae Production

Bo Li


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Highlights of Key Findings for DON

Developed method to separate coconuts and

bananas Hydrophobic DON was not bioavailable

to algae in tests

Protocol developed to minimize effect ofinorganic N in samples

20-25% of effluent DON was recalcitrant for

plants with low effluent TN (


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Hydrophobic Fractions of

WWTP Effluent DON

0.0

0.5

1.0

1.5

2.0

TMWRF KWWTP BRWRF SJWTP NDWRF SDWRF NAWTP RVWTP

Location

DON

(mg

N/L)

Whole effluent

Hydrophobic DON

Hydrophilic DON

A


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Highlights of Key Findings for DP

For tertiary treatment with chemicals the %

bioavailable (bananas) decreased with

increasing chemicals and lower effluent DP

The recalcitrant effluent DP fraction ranged

from 10 to 80% depending on the degree of

treatment

P in humic substance was not bioavailable

% Bi il bl P i Effl t TP


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% Bioavailable P in Effluent TP

Decreases as Effluent P Decreases

for Tertiary Chemical Treatment

0

20

40

60

80

100

10100100010000

BAP%&TP

Model Predicted

TP (ug/L)

BAP%

City of Spokane

pilot plant


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For Other Facilities Tested % BAP Varied

from 10-50% for TP from 0.02 to 0.20 mg/L

0

20

40

60

80

10100

Model Predicted

NDWRF

SDWRF

MBR

CUMF

1st BW

TMF

MSWTP

TP (ug/L)

BAP%

i d h bi i


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If coconut will turn to banana?

Investigate Hydrophobic Separation on

BAP and Long Term BAP Analysis

Wh i h Si ifi


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What is the Significance

of These Results?

Not all effluent N and P species from nutrient removal

WWTPs behave the same

Water quality models do not adequately consider speciation of

N and P with different bioavailability

For very low effluent TP and TN goals the fraction of P andN that is recalcitrant is more significant and more difficult

to remove

Methods are available to evaluate recalcitrant fractions of

effluent DON and DP Tool may be used to understand why some facilities have

much higher effluent DON


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QUESTIONS?

Many thanks to Professor David Sedlak, Michael Brett, Scott

Smith and April Gu and Dr. Haizhou Liu and Joonseon Jeong

and Bo Li and WERF supporters for making this possible.


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Dave Clark, P.E.

HDRs National Director of Wastewater; leads strategicefforts in understanding wastewater market issues as they

affect HDR clients

Over 25 years of experience in the wastewater industry

Works with local offices and business class technical

leads to outline technical skills needed to assist clients in

managing wastewater

Managed a broad range of wastewater projects ranging

from planning to detailed design and construction

management, to discharge permit negotiations and TMDL

Implementation Plans


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Nutrient Removal

Managing Water Quality Translating Research

to PracticeWERF Webinar

October 5, 2011

David L. ClarkHDR Engineering

[email protected]


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Nutrient Removal

Managing Water Quality

Translating Research to Practice Regulatory Trends

Numeric Nutrient Standards

Treatment Technology Issues Regulatory Solutions

Discharge Permitting

Key Nutrient Management

Issues


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Nutrient Removal

Regulatory TrendsNumeric Nutrient Standards


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Nutrient Removal

Acting Assistant Administrator Nancy Stoners March 16, 2011

Memorandum to EPA Regional Administrators

Working in Partnership with States to Address Phosphorus and NitrogenPollution through Use of a Framework for State Nutrient Reductions

place new emphasis on working with states to

achieve near-term reductions in nutrient loadings."

nitrogen and phosphorus pollution has the potentialto become one of the costliest and the most

challenging environmental problems we face

It has long been EPA's position that numeric nutrient

criteria targeted at different categories of water bodies

and informed by scientific understanding of the

relationship between nutrient loadings and waterquality impairment are ultimately necessary for

effective state programs.

EPA will support states that follow the framework but,

at the same time, will retain all its authorities under

the Clean Water Act


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Nutrient Removal

Challenges in Establishing Nutrient Criteria

F 150 mg/m2 Chla D 1,250 mg/m2 Chla

Scientific and Technical Basis for

Montanas Numeric Nutrient Criteria

Identifying Threshold of Harmto Beneficial Uses

Numeric Nutrient Criteria

Stressor Response

Response Variables D.O., pH

Chla, Benthic Algae

Macroinvertebrates

Fisheries

Recreation/PublicPerception

Translation of In-stream

Criteria to Effluent Discharge

Permit Limits

Typical Concentrations ThatProtect Uses Are Low MikeSuplee, MDEQTotal Phosphorus 0.05 mg/lTotal Nitrogen 0.30 mg/l


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Nutrient Removal

Treatment Technology Issues

Regulatory Solutions


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Nutrient Removal

Water Quality and

Advanced Wastewater Treatment Waterbody Numeric Nutrient Standards

Based on Natural Conditions Are Very

Low

Lower Than Treatment Technologies

Are Capable of Achieving If AppliedEnd-of-Pipe

Effectiveness of Advanced Treatment

for Nutrient Removal

Variability in Treatment Performance

Reliability Effluent Speciation

Bioavailability

Translation to Discharge Permits

303(d) Impairment Listings and TMDLs

Direct Application to Discharge Permits

Ideal Median Reliable

Neethling, JB; Stensel, H.D.; Parker, D.S.; Bott, C.B.; Murthy, S.;

Pramanik, A.; Clark, D. (2009) What is the Limit of Technology

(LOT)? A Rational and Quantitative Approach. Proceedings of the

WEF Nutrient Removal Conference, Washington DC, Water

Environment Federation, Alexandria, Virginia.

Treatment Performance Statistics


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Nutrient Removal

Regulatory Solutions Water Quality Variances,

Treatment Technology Standards, Affordability Tests

Key Areas

Permit Requirements

Below the Capabilities ofWastewater Treatment

Technology

Water Quality Variances

Treatment TechnologyLimits

Affordability Tests

Case Study Examples

Montana Senate Bill 95 andSenate Bill 367 Affordability Test (1% MHI)

Limit of Technology

Treatment Technology Std(TP 1 mg/L, TN 10 mg/L

Wisconsin Dual Legislation Numeric Nutrient Criteria

Treatment Technology Standard

Adaptive Management

Colorado New Regulation #85 Numeric Nutrient Criteria

Treatment Technology Standard

Adaptive Management


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Nutrient Removal

Wisconsin

Midwest Environmental Advocates Notice ofIntent to Sue EPA Nov 23, 2009

Failure to Perform its Non-discretionary

Duty to Promulgate Numeric Nutrient

Criteria

2010 Rulemaking

Phosphorus Criteria for Streams

Streams 0.075 mg/L

Large Rivers 0.100 mg/L

Chapter NR217 Effluent Standards and

Limitations for Phosphorus

Implementation by AdaptiveManagement

Watershed Adaptive Management Option

NPS + Stormwater

Numerical EffluentLimitations

1st Permit

TP 1 mg/L

Rolling 12 Mo. Ave

2nd Permit

TP


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Nutrient Removal

Colorado Initial Nutrient Criteria for Rivers and Streams

February 9, 2010

Selecting Numeric Nutrient Criteria That Allow

5% Decrease in Biological Condition

Multi Metric Macroinvertebrate Index

Regulation #31 Basic Standards and

Methodologies for Surface Water

New Section 31.17 Nutrient Interim Values After May 31, 2017 and Prior to May 31, 2022

Regulation #85 Nutrients Management

Control Regulation Establishes Numerical Effluent Limitations

Existing Plants

First Level BNR (3-stage)

TP 1 mg/L

TIN 10 mg/L

New Plants

Enhanced BNR (4 & 5-stage)

TP 0.7 mg/L

TIN 7 mg/L

Running Annual Median

Rivers and Streams Cold Water Warm Water

Chl a mg/m2 150 150

TP, ug/L 110 160

TIN, ug/L 400 2,000


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Nutrient Removal

Montana 150 mg Chla/m2 Considered

Nuisance Threshold by Public

Rarely Occurs in Western

Montana Reference Streams

Harm-to-Use Threshold for

Salmonid Streams Salmonid Growth Enhanced by

Productivity Up to 150 mg Chla/m2

DO Problems Begin at Higher Levels

150 mg Chla/m2 More Common

in Prairie Streams (E. MT)

2009 Senate Bill 95 Variance Temporary Nutrient

Standards

Economic Hardship

Substantial and Widespread

Targeted 1% MedianHousehold Income

Limits of Technology

2011 Senate Bill 367

MDEQ TP = 0.100 mg/L TN 5

mg/L Monthly Average

League of Cities TP = 1 mg/L

TN 10 mg/L Seasonal Average

F 150 mg/m2 Chla D 1,250 mg/m2 Chla


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Nutrient Removal

Discharge Permitting

Key Nutrient Management Issues


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Nutrient Removal

Appropriate Discharge

Permit Guidance for Nutrients Translation water quality criteria to

NPDES to permit limits

Critical interpretation of water quality

issues

Pre-formulated permit guidance

from EPA and States often focused

on toxics

Appropriate averaging periods Variability in low nutrient plant

performance

Over-specifying effluent discharge permit limits will not

provide significant additional water quality protection


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Nutrient Removal

Nutrients Differ from ToxicsNutrients

No Immediate Impact

Aside from Ammonia

Watershed Scale Impacts

Nutrient Enrichment Leads toAquatic Growth

Algal Response Over

Longer Periods

Longer Averaging Period

Appropriate for Nutrients

Seasonal or Annual Averages

Appropriate

Treatment Technology

Variability at Low Levels in the

Best Technologies

Toxics

Acute and Chronic Impacts

on Aquatic Life

Chlorine, Metals, Organics

Near-field (mixing zone) andFar-field (watershed)

Impacts

Long Term Response

Average Limits

Short Term Response

Maximum Limits Required


Available Technology to

Prevent Excursions


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Nutrient Removal

Permit Structure Long Term Seasonal

Averages, Seasonal Mass LimitsKey Areas Translation of TMDL

Requirements to Effluent

Discharge Permits

Appropriate Averaging Periodsfor Nutrient Limits

Maximum Day and Maximum

Week Dilemmas

Effluent Mixing Zones

Permit Requirements Below theCapabilities of Wastewater


Novel NPDES Permit

Approaches

Case Study Examples

Chesapeake Bay TMDL

Jim Hanlon Memo on Annual Averaging

Nitrogen and Phosphorus

Tualatin River Clean Water Services

Seasonal Median TP Concentration Las Vegas Wash City Las Vegas, CCSD,

Henderson

Seasonal Mass TP Loading Shared

Between 3 Dischargers

Spokane River DO TMDL

Seasonal Mass Loading Limits forPhosphorus, NH3N, CBOD

Coeur dAlene (Region 10 EPA)

Spokane County (Washington Ecology)


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Nutrient Removal

NPDES Permitting Regulations

40 CFR 122.45(d) requires that all permit limits be

expressed as average monthly limits and average weekly

limits for publicly owned treatment works (POTWs) and

as both average monthly limits and maximum daily limitsfor all others, unless impracticable.

Individual permit wri ters in every nutr ient limited watershed must interpret these

NPDES regulations and the definition of impracticable with limited guidance

Maximum monthly, weekly, and daily limi ts likely to be exceeded by even the best

designed and operated low nutrient treatment facil ities

Effluent N and P concentration is h ighly variable for even the best designed andoperated low nutrient treatment facili ties


68/77

Nutrient Removal

Case Study: Chesapeake BayDaily Maximum, Weekly Average andMonthly Average Limits Not Mandatory

Guidance from EPA Headquarters

Office of Wastewater Management

Annual Permit Limits for Nitrogen

and Phosphorus for PermitsDesigned to Protect Chesapeake

Bay

permit limits expressed as an

annual limit are appropriate and

that it is reasonable in this case

to conclude that it is

impracticable to express permit

effluent limits as daily maximum,

weekly average, or monthly

average effluent limitations.

Jim Hanlon, Office of WastewaterManagement, March 3, 2004


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Nutrient Removal

Variety of Successful Permit Structures

Nationally for NutrientsLocation Total Phosphorus

LimitsComments

Clean Water Servicesof Washington

County, OR

0.100 mg/l Monthly Median, May 1to Oct 31

Watershed Permit

Las Vegas, ClarkCounty, Henderson, NV

334 lbs/day(130/174/30 lbs/day)

Mar 1 to Oct 31Cooperative Agreementto Share for Flexibi lity

Alexandria, VA 0.18 mg/l and 37 kg/day

0.27 mg/l and 55 kg/day

Monthly Average

Weekly Average

Concentration Only, Mass Only, Both Seasonal Limits

Mean or Median

Shared Capacity

Case Study Example: Spokane River Dischargers


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Nutrient Removal

(Washington Ecology, Idaho DEQ, EPA Region 10)

Dissolved Oxygen TMDL

Very Restrictive

Cumulative Anthropogenic

D.O. Depression


71/77

Nutrient Removal

Permit Structure Effluent LimitsMass and Concentration

Long Averaging Periods

Preferred

Maximum monthly, weekly, and

daily limits likely to beexceeded by even the best

designed and operated low

nutrient treatment facilities

Individual permit writers in

every nutrient limitedwatershed must interpret these

NPDES regulations and the

definition of impracticable

with limited guidance

Mass Only

Mass Limits Provide Greater

Flexibility

Supports Effluent Reuse

Supports Trading/Water QualityOff-sets


72/77

Nutrient Removal

Permit Structure Nutrient Speciation

and BioavailabilityKey Areas

Low N and P Effluent

Speciation

Refractory N and P Not Biodegradable

Bioavailability?

Effluent Limits Based on Total

or Inorganic N and P?

Inorganic Limits Avoid

Refractory Constituents

Case Study Examples

Onondaga Lake TMDL, Syracuse,NY

Onondaga County (NYDEC)

Spokane River DO TMDL Spokane County (Washington

Ecology)

Coeur dAlene (Region 10 EPA)


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Question & Answer Session

To ask our speakers a question,

please follow the instructions

on the next slide.

Q & A


76/77

Q & A

Submit your text questions nowusing your Questions Window

Closing & Follow Up


77/77

Closing & Follow-Up

Thank you for participating!

As you leave todays session, an online survey

will follow. We appreciate your feedback.

This presentation has been recorded. A link to

the recording will be available at www.werf.org

later this week.

For more information, go to www.werf.org
http://www.werf.org/http://www.werf.org/http://www.werf.org/http://www.werf.org/

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Nutrient Removal:Costsand Benefits,Degrees of Difficulty, andRegulatory Decision Making

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