P REMOVAL: TREATMENT AND CAPABILITIES€¦ · TECHNOLOGIES AND CAPABILITIES Jane Madden, PE, BCEE Senior Vice President . CAWPCA . Fall Workshop . November 14, 2014 . ... • ACTIFLO

PHOSPHORUS REMOVAL: TREATMENT TECHNOLOGIES AND CAPABILITIES

Jane Madden, PE, BCEE Senior Vice President

CAWPCA Fall Workshop November 14, 2014

Agenda

• Phosphorus Removal Overview • Phosphorus Regulations in Massachusetts • Six Phosphorus Removal Case Studies • Summary and Questions

CAWPCA Fall Workshop

Phosphorus Fractions In Wastewater


Orthophosphate fractions Acid-hydrolyzable fractions Organic fractions

mg/

L ph

osph

orus

Insoluble (retained on f ilter)

Soluble (passes throughfilter)

Direct colorimetry

Sulfuric acid digestion & colorimetry

Persulfate digestion & colorimetry

0.45 µm filter

Analyses type

How is Phosphorus Removal Achieved?

• Convert soluble orthophosphates to a solid

• Remove solid – Biological solid

(microorganism) – Chemical solid

(precipitate)


Biological Phosphorus Removal


Secondary Clarifier

Aerobic

Return Activated Sludge

Waste Activated Sludge (TP ~4-7% of organic TSS)

Primary Clarifier

Preliminary Treatment

Anaerobic

Effluent TP < 0.75 mg/L

P RELEASE P UPTAKE

Pros and Cons of Biological Phosphorus Removal


• Pros – Sustainable treatment process – Low O&M costs – No chemical storage and feed systems – Less sludge production – Anaerobic selector provides improved sludge settleability

• Cons – Phosphorus re-release – Cannot achieve extremely low limits – Subject to upsets (like any biological process) – Can compete with biological nitrogen removal – Some plants report dewaterability issues

Chemical Phosphorus Removal


Dual point is more efficient than single

point

Return Activated Sludge

Waste Activated Sludge (TP ~ 2% of organic TSS

AND TP in Chemical Sludge)

Preliminary Treatment


Chemical (Metal Salts and Polymer)

Chemical (Metal Salts and Polymer)

(add-on or integrated process)


Chemicals (Metal Salts) Used for Phosphorus Removal

• Iron Salts – Ferric Chloride – Ferrous Sulfate

• Aluminum Salts – Alum – Poly Aluminum Chloride (PACl)

• Calcium Compounds – Quick Lime – Hydrated Lime


Pros and Cons of Chemical Phosphorus Removal


• Pros – Lower limits can be consistently achieved – No phosphorus re-release

• Cons – High O&M Cost – Increased sludge production and associated disposal costs – Chemical sludge can be more difficult to thicken and dewater – Additional chemicals for alkalinity control – Not sustainable

Processes to Achieve Low TP Limits (0.2 mg/L or less) (case studies)

• Add-On Processes with Chemical Addition – Filtration

• Conventional sand filters • Cloth media filters • Upflow filters

– Ballasted Flocculation • ACTIFLO® • CoMagTM

• DensaDeg®

• Integrated Processes – BioMag – Membrane Bioreactors (MBRs)


EPA Region 1 in Massachusetts Has Pushed the Envelope on Phosphorus Removal


Massachusetts Communities with Phosphorus Limits <0.2 mg/L


Regulations have Inspired Innovation

• Upgrade under construction – EBPR (A/O process) – Aquadisks and Aquadiamonds to achieve

0.1 mg/L summer, 0.3 mg/L winter – Bid Price: $17.4 M

Charles River Pollution Control District, Medway, MA

• Originally Constructed 1978 – 4.5 mgd

• Upgraded and Expanded 1998 to 5.7 mgd – Single-stage nitrification – Disk filters TP to achieve

0.2 mg/L seasonally


Filtration – Cloth Media


• Original facility designed by CDM Smith in early 1980s

• Average Daily Flow: 1.2 mgd • Total Phosphorus

– 0.2 mg/L (April – Oct) – 1.0 mg/L (Nov –Mar)

• Process: CoMag by Evoqua • First full-scale facility in the

world • Construction Complete 2007 • Construction Cost $13M


Concord, MA

Concord CoMagTM Ballasted Flocculation System


Reaction Tanks (Polymer Addition)

Alum Addition To CoMagTM Influent Piping

Settled Sludge

Optional Polishing Magnet

Clarifiers

Magnetite Recycling Drums

Performance Test Results – December 2007


0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

12/10/2007 12/12/2007 12/14/2007 12/16/2007 12/18/2007 12/20/2007 12/22/2007

Date

Tota

l Pho

spho

rus

[mg/

L]

Secondary Effluent

CoMag Effluent

Average tertiary effluent TP < 0.05 mg/L

Webster, MA

• Average Design Flow: 6 mgd • Total Phosphorus

– 0.2 mg/L (Apr – Oct) – 1.0 mg/L (Nov – Mar)

• Process: Actiflo by Kruger • Constructed within existing

abandoned tanks • Construction Complete:

Spring 2011 • Construction Cost: $8M


Ballasted Flocculation – ACTIFLO®


Recirculation Pumps

Treated Water

Settling Tank

Microsand

Coagulation Tank

Injection Tank

Maturation Tank

Raw Water Inlet

Sludge + Microsand

Coagulant Polymer

Hydrocyclones

Sludge

Marlborough Westerly WWTF

• Originally Constructed 1973 – 2.0 mgd

• Upgraded and Expanded 1988 to 2.89 mgd – Single-stage seasonal

nitrification • Upgraded and Expanded

2012 to 4.15 mgd – Single-stage year-round

nitrification – 0.1 mg/L (summer) – 1.0 mg/L (winter)

• Construction Cost: $27.5M • BluePro Filtration System by

BlueWater Technologies


Filtration – Upflow Filters


Dynasand Blue PRO®

Raw Water Inlet Clean

Water

Reject Stream

Wat

er

Particles

HFO- CS Grain

Fe

Fe

Fe

O

OAs

O

OPO4

3-

Facility Upgrade – Blue PRO® System


Filter Quad

Influent Channel

Weir Box

Effluent and Recycle Pipes

Air Control Panel

2012 Plant Performance

Description Permit/Design Values 2012 Values Flow (mgd)

Average Daily Flow 4.15 1.97

Maximum Daily Flow 7.5 4.5

Influent (mg/L)

CBOD 184 211

TSS 269 357

Phosphorus 6.1 7.9

Effluent (mg/L)

CBOD 15-25 0.89

TSS 15-30 1.82

Phosphorus – in season 0.1 0.086

Phosphorus – off season 1.0 0.13


Influent and Effluent Total Phosphorus (mg/L) April – October 2012


0

2

4

6

8

10

12

14

16

4/1/2012 5/1/2012 6/1/2012 7/1/2012 8/1/2012 9/1/2012 10/1/2012

Tota

l Pho

spho

rus (

mg/

L)

Influent Effluent

Marlborough Easterly WWTF

• Originally Constructed early 1970s – 5.5 mgd – Two-stage/two-sludge

process • Currently being upgraded

to meet TP limits – 0.1 mg/L (Apr-Oct) – 1.0mg/L (Nov-Mar)

• Two-stage process with A/O in first stage and BioMagTM in second

• Construction Cost: $44M


Integrated Process - BioMag


Upper Blackstone Water Pollution Abatement District (UBWAD) WWTF

• Serves greater Worcester, MA • 45 mgd ADF; 80 mgd MDF; 160 Peak hour • 3 Phase improvements plan completed in 2012 at a cost of

$180M


Facility Designed to Exceed 2001 Permit Limits Using Sustainable Process (EBNR – A2/O)


• Incorporated Nitrogen removal – Reduce O2 demand – Reduce chemicals for

alkalinity control • Biological phosphorus

removal • Gravity flow into and out of

treatment facility

Currently working with District to Optimize EBNR and Pilot Conventional Technologies

Process Optimization

• Conversion from caustic to magnesium hydroxide for alkalinity control

• Addition of real-time instrumentation and controls

• Operation in step feed under high flows

Pilot Studies

• Targeted addition of ferric chloride

• A2/O with supplemental carbon

• Modified Bardenpho with and without supplemental carbon


Innovative Technology – Advanced Biological Nutrient Recovery (ABNR)


ABNR Mimics the Natural Process in a Controlled Environment (PBR)

• Consumes CO2 • Releases O2

• Consumes nutrients • No chemical addition

required • Harvested algae is

potentially a beneficial product

• Can remove metals and other contaminants


Summary

• Each facility is unique and will have a unique solution for phosphorus removal

• Be cognizant of permit language – Push for seasonal average load or concentration – Consider regulating ortho-P vs. TP (to mitigate non-reactive P)

• Biological nitrogen and phosphorus removal are often competing reactions

• Phosphorus removal facilities can be costly to construct… • …And operate primarily due to power and chemicals

– Intermediate pumping; ancillary systems – Cost of chemicals (for coagulation and alkalinity) and increase

in sludge production


Questions?

Jane Madden, P.E., BCEE

CDM Smith [email protected]


Blue Pro

EBNR

Actiflo

BioMag

CoMag

Cloth Filters

Documents

P REMOVAL: TREATMENT AND CAPABILITIES€¦ · TECHNOLOGIES AND CAPABILITIES Jane Madden, PE, BCEE Senior Vice President . CAWPCA . Fall Workshop . November 14, 2014 . ... • ACTIFLO