Struvite

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5/24/2017

OPTIONS FOR SIDESTREAM PHOSPHORUS TREATMENT FOX RIVER WATER RECLAMATION DISTRICT BETH VOGT, JACK RUSSELL AND JAMES KERRIGAN FOX RIVER WATER RECLAMATION DISTRICT STEVE ARANT AND JAMES BARNARD BLACK & VEATCH

Central States WEA Annual Conference May 24, 2017 Saint Paul MN

AGENDA FRWRD Water Reclamation Facilities Fox River Implementation Plan and Effluent Phosphorus Limits Drivers for sidestream phosphorus removal Background on Struvite and Brushite Solubility Alternatives for sidestream phosphorus removal Fox River WRD evaluations 2

FOX RIVER WRD WATER RECLAMATION FACILITIES

IWPC | FRWRD Fermenters and Sidestream Phosphorus Removal

North WRF 7.75 mgd

ADP WRF 25 mgd

West WRF 5.0 mgd

4/25/2017

FOX RIVER IMPLEMENTATION PLAN AND EFFLUENT PHOSPHORUS LIMITS

IWPC | FRWRD Fermenters and Sidestream Phosphorus Removal

4/25/2017

NUTRIENT PLANNING • Fox River Study Group formed in 2001 • Preparation of Fox River Implementation Plan / TMDL • Address low dissolved oxygen and algae

• Current limit 1.0 mg/L TP annual average

• Planning performed at 0.5 mg/L, 0.3 mg/L and 0.1 mg/L TP, and 10 mg/L TN

IWPC | FRWRD Fermenters and Sidestream Phosphorus Removal

Phased Approach (example ADP WRF)

4/25/2017

IWPC | FRWRD Fermenters and Sidestream Phosphorus Removal

RECOMMENDED UPGRADES ADP WRF

Chemical Feed only needed for 1.0 mg/L monthly limit

4/25/2017

DRIVERS FOR SIDESTREAM PHOSPHORUS REMOVAL

DRIVERS FOR SIDESTREAM PHOSPHORUS REMOVAL • Reduce P & N recycle loads • Minimize nuisance scaling and deposits • Improve/recovery biosolids dewaterability • Recover fertilizer product • Decrease P content of biosolids

BACKGROUND ON STRUVITE SOLUBILITY AND IMPACTS TO DEWATERING

STRUVITE SOLUBILITY • Struvite Reactor pH 7.5 to 8.5 • NH4-N+ and Mg2+ at optimum ionic form • Low activity of PO4-P 3-

Struvite - MgNH4PO4.6H2O Solubility Product, Ksp= [Mg2+]*[NH4+-N]*[PO43--P]

Need to monitor for ionic strength (conductivity/dissolved solids)

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STRUVITE SOLUBILITY • Struvite less soluble above and below 35 °C

MD. IQBAL HOSSAIN BHUIYAN M.Sc, UENSCO-IHE Institute for Water Education, 2002

13

DEWATERING • Plants that have converted to Bio-P have experienced deterioration in dewatering performance • Lower cake solids • Higher polymer dose

• Two competing theories • High orthoP • High monovalent

Residual ortho-P or MV/DV cation ratio?

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ALTERNATIVES FOR SIDESTREAM PHOSPHORUS REMOVAL

FRWRD | Phosphorus Removal Improvements Project

8/29/2016

ALTERNATIVES FOR SIDESTREAM PHOSPHORUS REMOVAL Technology

AirPrex TM NuReSys TM Ostara TM Multiform Harvest TM

Number of Municipal Installations

6 Operational (Europe) 3 In final design (US) 3 Operational (Europe) 14 2 2 1

Operational (US) In construction/design Operational (US) In construction

Date of First Municipal Installation 2009 2013 (first industrial 2006) 2007 2012

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OSTARA • Leader in P recovery •

14 in operation

• Produces struvite “Pearl” • Two general flow schemes • •

Recover on centrate Recover on centrate + filtrate (WASSTRIP)

• WASSTRIP • •

Maximizes P recovery $300 to $400 per dry ton

• Reactor has recycle •

Lowers concentrations and increases size of reactor

OSTARA • WASSTRIP • Maximizes P recovery • $300 to $400 per dry ton

• Reduces struvite scaling potential, but may not eliminate it • Reduces impacts to dewatering? • WASSTRIP more complex process than recovering from centrate. • Need for additional WAS thickening process Stickney Ostara Reactor with Recycle Pumps

MULTIFORM HARVEST • Two general flow schemes • Recover on centrate • Recover on centrate + filtrate (MultiWAS) • Alternative flow schemes for MultiWAS

• No recycle flow • High concentrations reduces size of reactor

• MultiWAS •

Maximizes P recovery



$200 to $375 per dry ton

• Produces struvite crystals suitable for fertilizer blender

MULTIFORM HARVEST

ALTERNATIVE MULTIWAS?

MULTIFORM HARVEST • MultiWAS • Maximizes P recovery • $200 to $375 per dry ton

• Reduces struvite scaling potential, but may not eliminate it • Reduces impacts to dewatering? • MultiWAS more complex process than recovering from centrate. • Need for additional WAS thickening process

West Boise Multiform Reactor

AIRPREX • Precipitates struvite within digested sludge • Sequestration: crystals remain in biosolids • Recovery: crystals separated from biosolids • Alternative flow schemes available

• Air added to release CO2 and raise pH • MgCl2 is added to control effluent phosphate

• “Grit washer” used for struvite recovery • Up to $150 per dry ton

AIRPREX • Recovers dewatering to near pre-BioP levels • Reduces/eliminates struvite scaling • Up to $150 per dry ton • No full scale installations in US, 6 full scale in Europe • Numerous pilots in US, three plants in final design • Reduced chemical needs • Recovery of up to 50% of struvite crystals AirPrex Reactor Berlin Water

MGCL2 DOSAGE AND SCALING POTENTIAL PO4-P3-

NH4-N+

Mg2+ %Saturation Courtesy Dr. Zhongtian Li, CNP

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NURESYS • Precipitates struvite within digested sludge • Alternative schemes available • CO2 Release Tank • Air added to release CO2 and raise pH • Precipitate struvite with residual Mg • Struvite Reactor/Settler • MgCl2 is added to control effluent phosphate • Cyclone used for struvite recovery

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NURESYS • Recovers dewatering to near pre-BioP levels • Reduces/eliminates struvite scaling • Currently does not offer revenue for product • No full scale in US • Three full scale in Europe

CO2 Release Struvite Reactor/Settler

• Reactor/Settler reduces reactor size • Smaller add on for recovery • Recovery of up to 50% of struvite crystals

NuReSys Pilot Stevens Point

EVALUATION OF SIDESTREAM PHOSPHORUS REMOVAL

PROCESS MODELING FOR ADP WRF • Two scenarios modeled • WASSTRIP (Ostara, Multiform Harvest) • Digestate (AirPrex, NuReSys) • Albin D Pagorski (ADP) WRF • Regional solids handling facility • ADP WRF - 25 mgd • North WRF - 7.7 mgd • West WRF - 10 mgd 28

WAS STRIP OP 280lb/d TP 670 lb/d MAP 0 lb/d

OP 490 lb/d TP 980 lb/d MAP 0 lb/d Raw Influent

OP 60 lb/d TP 460 lb/d MAP 0 lb/d OX1

AN1

PreAX2

AN2

AN3

OX2

OP 220 lb/d TP 240 lb/d MAP 0 lb/d

OP 50 lb/d TP 110 lb/d MAP 0 lb/d

OX3

Effluent

AN4

PreAX1

P release Tank Digester

Struvite Reactor

Fermenter MgCl2

Sludge from N Sewer N1

Sludge from W

Sewer N2

Sewer W1

Sewer N3

Sewer W2

OP 20 lb/d TP 300 lb/d MAP 0 lb/d

Sewer N4

Sewer N5

Sewer W3

BioSolids

Sewer N6

Sewer W4

OP 40 lb/d TP 590 lb/d MAP 0 lb/d

Struvite

OP 540 lb/d TP 1320 lb/d MAP530 lb/d

OP 140 lb/d TP 890 lb/d MAP500 lb/d

Digester OrthoP (OP to dewatering) = 370 mg/L

OP 10 lb/d TP 610 lb/d MAP4230 lb/d

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STRUVITE REACTOR ON DIGESTATE OP 0 lb/d TP 800 lb/d MAP 0 lb/d

OP 490 lb/d TP 980 lb/d MAP 0 lb/d Raw Influent

OX1 AN1

PreAX2

AN2

OX2

OP 20 lb/d TP 80 lb/d MAP 0 lb/d

OX3

Effluent

AN3

PreAX1

RAS DO Entrainment

Digester

Struvite Reactor BioSolids

Fermenter

Sludge from N Sewer N1 Sewer N2

Sludge from W

Sewer W1

Sewer N3

Sewer W2

OP 30 lb/d TP 280 lb/d MAP 0 lb/d

MgCl2

Sewer N4

Sewer W3

Sewer N5

Sewer N6

Sewer W4

OP 40 lb/d TP 530 lb/d MAP 0 lb/d

OP 710 lb/d TP 1610 lb/d MAP840 lb/d

OP 50 lb/d TP 1610 lb/d MAP6040 lb/d

Struvite Reactor OrthoP (OP to dewatering) = 30 mg/L

OP 10 lb/d TP 1500 lb/d MAP5860 lb/d

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RESULTS • WAS STRIP process results in relatively high orthoP concentrations to dewatering • Risk of struvite scaling and dewaterability issues • Struvite reactor on digestate is anticipated to recover dewatered cake solids to prebioP levels • Struvite recovery • WASSTRIP ~ 4,000 lb/d as MAP • Digestate ~ 2,800 lb/d as MAP • Phosphorus content of cake • WASSTRIP 1.8% P • Digestate 2.8% P w/o recovery, 2.1% P w/ recovery

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DEWATERING • Monovalent to Divalent Cation Ratio • Higgins and Novak

• Divalent cations bridge negatively charged extracellular polymeric substances • Threshold for poor settling/dewatering • MVeq/DVeq > 2.0 (based on equivalents, DV *2) 32

CONVENTIONAL PLANT – NO BIOP

MV/DV = 1.12

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BIO-P PLANT

MV/DV = 2.29

Release of K in Digester increases MV/DV Mg and Ca precipitate as phosphates

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WAS STRIP

MV/DV = 2.18

Remaining K and Mg still released in Digester Mg drops out as Struvite

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AIRPREX

MV/DV = 1.11 Magnesium added prior to dewatering

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AIRPREX – ORTHO-P TO DEWATERING VS. MONOVALENT/DIVALENT CATIONS

Need to monitor for Mg, Ca, Na and K

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3.0 2.0 1.0 0.0

Monovalent/Divalent

FOR AIRPREX PROCESS

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DESCRIPTION

MULTIFORM HARVEST™

OSTARA PEARL™

Total Probable Construction $17,400,000 $32,800,000 Cost

AIRPREX™

NURESYS™

AIRPREX™

PHOSPHORUS PHOSPHORUS PHOSPHORUS SEQUESTRATION SEQUESTRATION RECOVERY

NURESYS™

NURESYS™

PHOSPHOURS RECOVERY IN SLUDGE STREAM

PHOSPHORUS RECOVERY IN FILTRATE

$10,800,000

$10,600,000

$14,300,000

$11,100,000

$10,600,000

O&M Cost Chemicals

$197,000

$175,000

$175,000

$175,000

$175,000

$175,000

$120,000

Biosolids Management Cost Savings

($88,000)

($88,000)

($153,000)

($153,000)

($184,000)

($184,000)

($45,000)

Revenue Generated (fertilizer)

($112,000)

($169,000)

-

-

($76,000)

-

-

$87,000

$8,000

$82,000

$82,000

($25,000)

$51,000

$135,000

$199,000

$8,000

$82,000

$82,000

($25,000)

$51,000

$135,000

$11,100,000

$10,800,000

$13,200,000

$10,900,000

$11,500,000

Net Annual O&M Costs including Revenue Net Annual O&M Costs including Guaranteed Revenue Present Worth Costs Total Present Worth Costs including Revenue

$17,200,000 $30,900,000

Operating Parameters Phosphorus Content of Biosolids

1.9%

1.9%

2.8%

2.8%

2.3%

2.3%

1.9%

Volume of Biosolids Produced

6,000 ft3/d

6,000 ft3/d

5,400 ft3/d

5,400 ft3/d

5,100 ft3/d

5,100 ft3/d

6,400 ft3/d

Struvite Recovered

3,900 lb/d

3,900 lb/d

-

-

2, 300 lb/d

2,300 lb/d

3,700 lb/d

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www.bv.com

5/24/2017

OPTIONS FOR SIDESTREAM PHOSPHORUS TREATMENT FOX RIVER WATER RECLAMATION DISTRICT Central States WEA BETH VOGT, JACK RUSSELL AND JAMES KERRIGAN FOX RIVER WATER RECLAMATION DISTRICT STEVE ARANT AND JAMES BARNARD BLACK & VEATCH

Annual Conference May 24, 2017 Saint Paul MN

IWPC | FRWRD Fermenters and Sidestream Phosphorus Removal

Fox River Implementation Plan Flow Duration Curve for June-September (WY1960-2009) Flow Duration Curve

WQS Compliant Flow Rates

1000.0

Flow Rate (cms)

100.0

10.0

1.0

0.1 0

10

20

30

40

50

60

% of Time Flow Exceeded

70

80

90

100

4/25/2017

9 March 2017

ADP WRF PERFORMANCE Effluent OrthoP

Effluent Total P

Based Case, No phosphorus removal

4.0 mgP/L

4.1 mgP/L

BioP (no fermenter, no struvite reactor)

3.2 mgP/L

3.6 mgP/L

BioP with fermenter (no struvite reactor)

2.5 mgP/L

3.0 mgP/L

BioP with struvite reactor (no fermenter)

1.5 mgP/L

1.8 mgP/L

BioP with fermenter and struvite reactor

0.1 mgP/L

0.5 mgP/L