A Low Capital Approach for Performing Separate Centrate Deammonification

Greg Pace January 25, 2016

Acknowledgements

Kathleen O’Connor Sarah Galst Wendell Khunjar

Robert Sharp Dennis Daly Joshua Perez-Terrero

Allen Deur Sal Scapelito

Kartik Chandran

26th Ward WWTP

85 mgd 3 Aeration Tanks,

1 Aeration Tank dedicated to Separate Centrate Treatment (SCT )

•  Receives digested sludge from other WWTPs

•  ~33% of influent load to

secondary treatment is from centrate

26th Ward utilizes nitrification and denitrification for centrate treatment

AOB

denitrita)on

1molAmmonia(NH3-N)

1molNitrite(NO2--N)

1molNitrate(NO3--N)

1molNitrite(NO2--N)

1/2molNitrogengas(N2)

75%O2

25%O2

60%Carbon

40%Carbon

nitrita)on

nitrata)ondenitrata)on

•  CurrentapproachforSCTusesnitrifica)onanddentrifica)on•  4.57gO2/gNH4-N•  6gglycerinasCOD/gN

NOB

AOB

Implementing deammonification would reduce operating costs

Key requirements for commercial deammonification Anoxic conditions

Simultaneous presence of ammonia and nitrite NOB suppression

Long SRT Selective retention of anammox

1molAmmonia(NH3-N)

1/2molNitrite(NO2--N)

37.5%O2

nitrita)on

1/2molNitrogengas(N2)&SmallamountofNitrate

AOBAnammox

ANAMMOX ANITAMOX DEMON CLEARGREEN

Proprietaryreten9onstrategy Tiltedplatese>ler

Plas9ccarrierandscreen hydrocyclone SBRControl

Implications for 26th Ward and other SCT facilities

Significant retrofit of tanks and equipment

Acquisition of proprietary devices/controls

Need for seed sludge to start reactors

BUT

Significant upside in terms of operating energy and costs using anammox based technology

$-

$500,000

$1,000,000

$1,500,000

$2,000,000

$2,500,000

Yearlyestim

ated

ope

ratin

gcost

($/year)

SCTWithGlycerol Deammonification

Canweimplementsimilartechnologyinmorecosteffec)vemanner?

Glycerol addition results in nitrite accumulation

0

5

10

15

20

25

30

0 30 60 90 120 150 180

Con

cent

ratio

n (m

g N

/L)

Time(min)

Nitrite

Nitrate

Ammonia

Simultaneous presence of nitrite and ammonia under anoxic conditions typically used in sidestream anammox systems

Revised approach for facilitating deammonification

1molAmmonia(NH3-N)

1/2molNitrite(NO2--N)

1/2molNitrate(NO3--N)

37.5%O2

12.5%O2 20%Carbon

nitrita)on

nitrata)on

denitrata)on

Anaerobicammoniaoxida)on 1/2molNitrogengas(N2)

&SmallamountofNitrate

•  Fullnitrifica)onanddenitrata)onof50%centrate•  Revisedapproachcanyieldsignificanttheore)calsavings

•  50%Oxygen•  80%Carbon

AOB

NOB

Anammox

Heterotrophic

Aerate (nite) AnammoxAnoxic(denite)

CentrateFeed

CentrateFeed

Settle Decant

Glycerol Feed

Time

0.5 Hr 24 Hr 1 Hr 0.5 Hr 16 Hr 2 Hr 1 Hr

0

10

20

30

40

50

60

70

80

90

0 8 9.67 23.34

Concen

tration(m

g/L)

Time(hours)

Nitrate Nitrite Ammonia

6.4 6.6 6.8 7 7.2 7.4 7.6 7.8 8 8.2

0 5

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

0 8 9.67 23.34

pH

Con

cent

ratio

n (m

g/L)

Time (hours)

Reactor B Nitrate Nitrite Ammonia pH

anammox

aerobic

anoxic anammox

Aerobic Anoxic

Glyceroladdi9on

Proof of Concept

Anammox

Centrateaddi9on

Centrateaddi9on

Current Progress

Pilot setup

Centrate Pump Storage

tank SBR

Glycerol dosing pump

Inclined plate settler

Effluent to main plant

DOprobeandmeter

pHprobeandmeter

Aircompressor,airflowmeter;airflowcontroller/spliZer

To plant drain (manual) To plant drain

(manual)

Mixerandimpeller

Reactor feed pump

Return sludge pump (manual)

TempandTSSprobeandmeter

Finebubblediffusers

Pilot setup

EffluentfromplateseZlergoestodrain

Underflowispipedtoreturnsludgetothereactor

Reactor

SeZler

Basis of Operation

0

CycleTime(hr)

24 48

CentrateFeed

AerobicPhase AnammoxPhase

Glycerolfeed

Denitrata)onPhase

•  Duringenrichment,noglycerolfeed•  Aerobicphasevariesfrom8to24hrs•  Deammonifica)onphasevariesfrom24to42hrs

Operational parameters

Key Parameters •  HRT = 48 hr (matches full-scale HRT) •  SRT > 50 day

•  Target TIN loading ~ 0.25 kg N/m3-day

Process control strategy •  Grab samples 5 days a week (NH3, NO2, NO3, ortho-P, alkalinity) •  Weekly activity tests

•  Adjust airflow in response to grab samples •  DO monitored; not used for control

•  Adjust loading in response to activity tests

•  pH monitored

Approach for Enrichment of Anammox

Manipulate N Loading Rate to

Reactor

Weekly Anammox Activity Batch testing

Maximumpoten)alanammoxac)vity

MonitorEffluentQuality

TargetLoadingNloading=0.25kgN/m3-day

Overall progress

TINLoadingRate(KgN/m

3-day)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0

10

20

30

40

50

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90

100

1/5/20

15

1/25

/201

5

2/14

/201

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3/6/20

15

3/26

/201

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/201

5

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/201

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/201

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10/12/20

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5

11/21/20

15

TINPercentRem

oval(%

)TIN%Removal TINLoadingRate

Period 1 Period 2 Period 3 SS

Nitrogen Removal Performance

0.00

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0.30

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15

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5

11/21/20

15

TINPercentRem

oval(%

)TIN%Removal TINLoadingRate

Period 3 SS

Avg. Loading = 0.2 kg N/m3-day Avg. TIN Removal = 63%

Nitrogen removal profile

TIN removal occurring during the aerobic period… Looking into:

•  Heterotrophic denitrification •  Nitrous oxide production •  Anammox (granule)

0

50

100

150

200

250

300

0 4 8 12 16 20 24 28 32 36 40 44 48

Nitrogen

Con

centratio

n(m

gN/L)

CycleTime(hours)

NH3 TIN NOx

Aerobic Cycle Anoxic Cycle

Nitrous Oxide Production

Results indicate that nitrogen oxide production is present and can account for ~3% of the total ammonia removed from the system

0

500

1000

1500

2000

2500

0

5

10

15

20

25

30

12:00PM

6:00

PM

12:00AM

6:00AM

12:00PM

6:00

PM

12:00AM

6:00AM

12:00PM

Gaseou

sN2O

(ppm

v)

Time(hr)

NitrousOxide NitricOxide

Gaseuo

usNO(p

pbv)

Aerobic Cycle Anoxic Cycle

Aerobic Cycle

Nitrite production is significant N loss occurs in aerobic cycle

Free ammonia to MLSS = 1.8 mg Free ammonia as N/g MLSS

0

10

20

30

40

50

60

NO3Produced NO2Produced MLSS+N2O+N2

%ofN

H3Re

moved

inAerob

ic

Cycle

FA/MLSS

0

1

2

3

4

55/26

/2015

6/25/201

5

7/25/201

5

8/24/201

5

9/23/201

5

10/23/2015

11/22/20

15

Ratio

Date

FA/MLSS

Anoxic Cycle

Nitrogen removal driven by combination of anammox and denitrification

y=1.1918x

0

20

40

60

80

100

120

0 10 20 30 40 50 60

Nitrite

Con

sumed

(mgN/L)

AmmoniaConsumed(mgN/L)

Strous et al. 1998

Lessons Learned •  Rapid heat loss suppresses anammox activity

•  High operating DO (~2 mg/L) during enrichment speculated to suppress anammox activity

•  Anammox can occur in low DO environments, increasing the overall nitrogen removal efficiency of the SCAD Process

•  NOB repression is present – Although not desired, high free ammonia loading and strict airflow control resulted in NOB repression.

•  Glycerol addition may benefit the process, however, is not required to achieve high removal rates

Conceptual strategy for promoting anammox growth in SCT

A

B

D

RASfrommainplant

InclinedplatesettlerunderflowcontainingAnammox bacteria

InternalRecycle

Centrate

C

SCADeffluenttomainplant

Inclinedplatesettleroverflowtomainplant

GlyceroladditionAerobiczone-Nitrification

Anoxic-Denitratation

DeammonificationAnoxic-Denitritation

Current Status and Next Steps

•  Molecular analyses

•  Conceptual Design

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1/31/2015

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7/30/2015

TINPercentRem

oval

(%)

TNLoa

ding

Rate

(kgN/m

3-day)

TNLoadingRate TIN%Removal

Concluding thoughts

Despite issues with centrate supply and power, system recovers quickly

Questions and Contact Information

Wendell Khunjar wkhunjar@hazenandsawyer.com Sarah Galst sgalst@hazenandsawyer.com Gregory Pace gpace@hazenandsawyer.com

N Removal Performance and Activity Methods

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1.2

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5

HydrazineAssay

(mgN/gVSS-hr)

Trad

ition

alAssay

(mgN/gVSS-hr)

Traditional Hydrazine