balancing nutrient limits with net environmental benefits · appropriate discharge permit guidance...

Balancing Nutrient

Limits with Net

Environmental

Benefits JB Neethling

HDR Engineering

2013 Technical Conference and Exposition

Ohio Water Environment Association (OWEA)

Mason, OH

June 18-20, 2013

Copyright 2013 HDR Engineering, Inc. All rights reserved.

Outline

Regulatory Drivers

Treatment Performance Reliability

Sustainability Impacts for Various

Treatment Levels

Next Steps

Regulatory Drivers

8

EPA’s National Nutrient Strategy

Nutrient Criteria Strategy,

1997

Ben Grumbles’ May 25, 2007,

memorandum to States

“…Numeric standards

reduce States’ time and

effort to establish TMDLs

and permits to control

nutrient levels…”

EPA developed ecoregional

criteria for rivers and

streams that define the in-

stream concentrations

Ecoregional Criteria are low: TP = 0.010-0.076 mg/L TN = 0.12-2.18 mg/L

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

additional water quality protection but may result in compliance issues

Nutrient Criteria and Approaches Developed by

Various States

State TN (mg N/L) TP (mg P/L) Comment

Colorado 0.824 – 1.316 0.090 – 0.135 Use observable biological potential

(OBP)

Florida 0.67 – 1.87 0.06 - 0.49 Streams - Florida Department of

Environmental Protection*

Idaho - 0.070 TMDL downstream of Boise River

Montana 0.130 – 1.358 0.011 – 0.123 Summer in-stream criteria (summer) for

various subregions.

Montana 0.3 0.03 River specific seasonal limits.

SF Bay Area - - Numeric nutrient endpoints using WQ

modeling underway?

Washington - 0.004 - 0.035 Nutrient control plan, based on eco-

region values

Wisconsin - 0.015 – 0.100 Proposed based on scientific concepts

Adapted from Clark et al. (2010) * Implementation of Florida’s

Numeric Nutrient Standards

(March 2013)

Variety of Successful Permit Structures

Nationally for Nutrients

Nutrients Differ from Toxics

Concentration Only, Mass Only, Both

Seasonal Limits

Mean or Median

Shared Capacity

Limits are low

Approaching technically achievable

limits (barring RO)

Instream standards could apply end-

of-pipe

Adaptive Management Approach

used by some

F 150 mg/m2 Chla

D 1,250 mg/m2 Chla

Proposed Permit Limits in Various States/Utilities

State/Region TN (mg N/L) TP (mg P/L) Comment/Basis

Colorado 15 / 2 1.0-1.5 Adaptive management approach.

Florida ? ? Hierarchical Approach to achieve

Narrative Nutirent Criteria (TMDL,

SSAC, WQBEL, weight of evidence)

Kansas 8 1.5 Technology based & affordability

criteria

Maryland 4 0.3 Defined ENR; Annual mass loading

allocations

Montana 5-10 0.1-1.0 Technology based interim

Montana 10 1.0 Legislation passed; Variance defined.

Ohio 10 (TIN) 1 Initial limits

Puget Sound - - WQ modeling/TMDL pending. Puget

Sound 2 mg/L TIN.

Spokane

River

- TMDL Seasonal monthly loadings. DO

modeling.

Virginia 3 – 6 0.18 – 0.4 Annual mass loading; Ches. Bay

nutrient DO, chlorophyll-a criteria

TMDL.

Wisconsin Postponed 0.5 – 1.0 State legislation establishes adaptive

management approach

Treatment

Performance

Reliability

17

What is the “Performance” for This Real-World

WWTP Dataset?

0.001

0.01

0.1

1

10

0.001

0.01

0.1

1

10

Dec-04 Jul-05 Dec-05 Jul-06 Jan-07 Jul-07 Jan-08

--

Central (all), TP

Lowest value?

“Next” Lowest value? “Repeated” Low value?

“Average” Value?

“Reliable” Value?

Three TPSs shown

TPS-14d (3.84%)

Ideal Performance

14-day performance level

TPS-50%

Median Performance

“Average” performance

TPS-95%

Reliable Technology Achievable Performance

6/19/2013 19

1% 10% 25% 75% 90% 99% 99.9%0.1% 50%

0.00

0.01

0.10

1.00

10.00

Percent of values less than of equal to indicated value

mg

/L

SE TP (all)

2

5

2

5

3.84%

0.040

50%

0.080

95%

0.23

Define Performance on a Statistical Basis

Neethling et al. (2009) WEF Nutrient 2009, Alexandria, VA.

Ideal Median Reliable

14-day Values Can Vary – Using Rolling

Average

0.001

0.01

0.1

1

10

Dec-04 Jul-05 Dec-05 Jul-06 Jan-07 Jul-07 Jan-08

-

Central (all), TP Central (all), TP14

2005: 0.036 mg/L

2006: 0.044 mg/L 2007: 0.038 mg/L

Technology Performance Statistics (TPS)

Proposal suggested by Neethling, et al (2009) Technology Performance Statistics (best, median, reliable)

“Ideal”: TPS-14d representing the 3.84th percentile

“Median”: TPS-50% 50th percentile

“Reliable”: TPS-95% 90, 95, 99th, etc percentile depending on the permit averaging period and the reliability required by the owner/operator – 95th of daily or monthly values used here

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. Ideal Median Reliable

TPS for Nitrogen Facilities Plant Process TPS-14d TPS-50% TPS-95%

Fiesta Village, FL BNR/N/Al, MeOH/DF 0.25 1.03 2.71

Kalkaska, MI BNR/N/P/Fe 0.31 0.75 2.4

Western Branch,

MD

AS. 3Nit, MeOH/3DN, Al/F 0.66 1.47 3.2

River Oaks, FL MeOH/3DN, F 0.78 1.45 2.92

Truckee

Meadows, NV

AS, 3Nit, MeOH/3DN, F 1.16 1.57 2.85

Piscataway, MD BNR/N/Al, F 1.3 3 8

Tahoe-Truckee,

CA

AS, Lime/Cla, 3Nit,

MeOH/3DN, Al/F

1.67 2.5 3.37

Eastern WRF, FL BNR/P/N, F 2.08 3.64 8.56

Parkway, MD BNR/N/MeOH 2.1 3.4 6.4

Adapted from Bott and Parker (2010)

TPS for Phosphorus Facilities Plant Process TPS-14d TPS-50% TPS-95%

Iowa Hill, CO AS. Al/Cla/F 0.004 0.012 0.045

Blue Plains, DC Pri/Fe. AS/Fe,

3Nit/MeOH/3DN, F

0.005 0.07 0.18

Pinery, CO BNR/N/P, Al/Cla/F 0.013 0.023 0.045

F. Wayne Hill, GA BNR/N/P/Al, Fe/Cla/F/MF 0.02 0.04 0.11

Rock Creek, OR Pri/Al, BNR/N, Cla/F 0.025 0.065 0.21

ASA, VA BNR/N/Fe, Al/Cla/F 0.025 0.05 0.12

Cauley Creek,

GA

MBR/N/P/Fe 0.04 0.08 0.16

Clark County, NV BNR/N/P, Al/Cla/F 0.045 0.081 0.201

Kalispell, MT BNR/N/P/Ferm, F 0.05 0.1 0.23

Kelowna, BC BNR/N/P/Al/Ferm, F 0.09 0.15 0.324

Adapted from Bott and Parker (2010)

80th and 95th Percentile Nitrogen Species in

Advanced Treatment

NH4-N = Ammonia; NOx = Nitrite + Nitrate; DON = Dissolved Organic Nitrogen; Part N = Particulate N

0

1

2

3

4

5

6

7

Part N NH4 NOx DON TN

Co

nce

ntr

atio

n ,

mg

N/L

Estimated Optimal P Species in Advanced

Treatment

SRP=Soluble Reactive P; SNRP = Soluble Nonreactive P PP=Particulate P TP = Total P

0

10

20

30

40

50

60

sRP sNRP Part P TP

Co

nce

ntr

atio

n ,

ug

P/L

Summary

In-stream criteria are very low

Translation stream criteria to permit limits is

challenging

Adaptive management provides a means to make

gradual progress

What are the sustainability impacts of lower limits?

Nutrient Removal

and GHG Emission

Tradeoff Between Nutrient Removal and

Sustainability

Determine sustainability impacts of five

levels of treatment for 10 mgd plant

Determine if there is a point of

diminishing returns for sustainability

with increased treatment

What Did We Consider for the

Triple Bottom Line?

Economic Pillar:

•Total Project Cost

•O&M Cost

Environmental Pillar:

•GHGs (Energy Demand, Chem

manufacturing/hauling, N2O,

biosolids hauling)

•Water Quality

•Ancillary Benefits of Increased

Treatment Social Pillar:

•Discussion in WERF Report

•Existing metrics (Health)

•Future metrics (Social)

Treatment Level Objectives

Level BOD

(mg/L)

TSS

(mg/L)

TN

(mg N/L)

TP

(mg P/L)

1 30 30 - -

2 <30 <30 8 1

3 <30 <30 4-8 0.1-0.3

4 <30 <30 3 0.1

5

<30 <30 2 <0.02

WAS

Primary

Clarifiers

Headworks Aeration Basins Secondary

Clarifiers

RAS

Primary Sludge

Influent

GBT

Discharge

CCT

Centrate

Centrifuge

Anaerobic

Digester

Sodium

Hypochlorite NaHSO3

Natural Gas to Cogeneration

Level 1 Schematic

WAS

Primary

Clarifiers

Headworks

ANX

Secondary

Clarifiers

RAS

Primary Sludge

Influent

GBT

Centrate

MLR

ANR Aerobic Zone

Alum

(optional)

Centrifuge

Anaerobic

Digester


Filters

Sodium

Hypochlorite

Discharge

CCT

NaHSO3

Alum

(optional)

Level 2 Schematic

WAS

Primary

Clarifiers

Headworks Secondary

Clarifiers

RAS

Filters

Primary Sludge

Influent

GBT

Sodium

Hypochlorite

Discharge

CCT

Spent Backwash

Centrate

MeOH

(optional)

ANR ANX AER

Alum

ANX AER

MLR

Centrifuge

Anaerobic

Digester

NaHSO3


Level 3 Schematic

WAS

Primary

Clarifiers

Headworks

RAS

Filters

Primary Sludge

Influent

GBT

Sodium

Hypochlorite

Discharge CCT

Spent Backwash

Centrate

MeOH

MLR

ANX

MeOH

(optional)

AER ANX AER ANR

Fermentation

Centrifuge

Anaerobic

Digester

NaHSO3


Alum/Polymer

Level 4 Schematic

WAS

Primary

Clarifiers

Headworks Secondary

Clarifiers

RAS

Primary Sludge

Influent

GBT

NaOCl Discharge

CCT

Spent Backwash

Centrate

MeOH

(optional)

ANR ANX AER Alum/Polymer

ANX AER

MLR

Centrifuge

Anaerobic

Digester

MF RO

RO Reject (20%)

Cl2, 1 ppm

NaHSO3


Filters

Rapid Mix/

Flocculation/High

Rate Clarification

Alum/

Polymer

MeOH

Level 5 Schematic

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 Optional

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)

System Inputs

(Thicken/Digest/Dewater)

Wastewater Collection Liquid Stream

Treatment

Discharge

Plant Boundary

Boundary for this Study

Biological Solids Treatment

GHG

Energy Production

GHG

Chem Mining, Manufacturing,

& Hauling

GHG

GHG

GHG GHG

Solids Disposal

GHG

Deep Well Injection (Level 5)

GHG

Biosolids Hauling

GHG Cogen

GHG

Tertiary Add-On Disinfection

GHG

GHG Distribution (10 mgd Plant)

-2,000

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000N2O Emissions (w/Data Range as Bars)

Biosolids Hauling and CH4 Emissions

Deep Well Injection

Aeration

ChemicalsPumping/Mixing

Miscellaneous

Cogeneration

CO2 eq mt/yr

Chemical Contributions to GHG

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

CO

2 e

qu

iva

len

t to

nn

es

/yr

Tertiary Chemical P

Other (Disinf/Dewater)

Methanol

Energy Contributions to GHG

0

2,000

4,000

6,000

8,000

10,000

12,000

CO

2 e

qu

iva

len

t to

nn

es

/yr RO & Brine disposal

Aeration

Pumping Mixing

Other

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 5

Inc

rem

en

tal G

HG

In

cre

as

e p

er

Ad

dit

ion

al

lb

NP

Re

mo

ve

d (C

O2

eq

lb

/N o

r P

lb

)

Incremental GHG Increase per Change in Treatment Level for N

Incremental GHG Increase per Change in Treatment Level for P

Incremental GHG ↑ per Additional lb

N or P Removed

3 18 23

338

0.5 16 190

3400

0

1,000

2,000

3,000

4,000

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

lb CO2eq/lb N lb CO2eq/lb P

Potential Algae Production (10 mgd Plant)

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

GH

G E

mis

sio

ns

(C

O2

eq

mt

ton

s/y

r)

Alg

ae

Pro

du

cti

on

pe

r T

rea

tme

nt

Le

ve

l (l

b a

lga

e/d

)

Algae Production GHG Emissions

What’s It Going to Cost You for a 10 mgd

Plant?

0

50

100

150

200

250

300

350

Level 1 Level 2 Level 3 Level 4 Level 5

Pre

sen

t W

ort

h C

ost

, m

illio

n $

Project, $M O&M, $M

Ancillary Benefits of Nutrient Removal

Lower BOD and TSS discharge load

Higher removal of micro-constituents and metals

Water more conditioned for filtration, disinfection,

and reuse applications

Fewer algal blooms

Greater process stability from the anaerobic/anoxic

zones serving as selectors

Sustainability Take Away Points

1. GHG impacts from all levels of treatment are

dominated by energy consumption

2. Levels 4 & 5 may have sustainability impacts that

outweigh potential water quality improvements

3. Why even discharge Levels 4/5?

4. Use a more holistic approach to watershed

nutrient management

M.W. Falk, JB Neethling, D.J. Reardon

HDR Engineering

WERF NUTR1R06n 2011

WERF Nutrient Challenge

Report Striking the

Balance Between Nutrient

Removal in Wastewater

Treatment and

Sustainability

For Additional Information:

JB Neethling [email protected]

Amit Pramanik [email protected]

WERF Nutrients knowledge area:

www.werf.org/nutrients

Balancing Nutrient

Limits with Net

Environmental

Benefits


JB Neethling

HDR Engineering

2013 Technical Conference and Exposition

Ohio Water Environment Association (OWEA)

Mason, OH

June 18-20, 2013


balancing nutrient limits with net environmental benefits · appropriate discharge permit guidance...

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