successful phosphorus removal and recovery phos.pdfnovember 20, 2014 jim fitzpatrick senior process...

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JIM FITZPATRICK SENIOR PROCESS ENGINEER

Successful Phosphorus Removal and Recovery

SOUTHWEST SECTION PLANT OPERATIONS SEMINAR MASON, OHIO

AGENDA

• Drivers and WWTP Sources • EBPR and Struvite Recovery • Recovery with Low Effluent Limits

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DRIVERS AND WWTP SOURCES

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PHOSPHORUS LINK TO HARMFUL ALGAL BLOOMS

November 20, 2014

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SWOWEA Plant Operations Seminar l

But much more complicated than just POTW effluent

Gulf of Mexico, 2007 (Courtesy of NASA)

Lake Erie, 2011

“The phosphorus content of our land, following generations of cultivation, has greatly diminished. It needs replenishing. I cannot over-emphasize the importance of phosphorus not only to agriculture and soil conservation, but also the physical health and economic security of the people of the nation. Many of our soil deposits are deficient in phosphorus, thus causing low yield and poor quality of crops and pastures…."

-President Franklin D. Roosevelt, 1938

MORE MOUTHS TO FEED INCREASES THE NEED FOR PHOSPHORUS

November 20, 2014

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HOW WILL WE MEET THE GROWING DEMAND?

November 20, 2014 SWOWEA Plant Operations Seminar l

From S. Van Kauwenbergh. (2010), World Phosphate Rock Reserves and Resources. Presented at Center for Strategic and International Studies

Recovery is part of long-term solution

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RETURN TO AGRICULTURAL ROOTS


From K. Ashley et al. A brief history of phosphorus: From the philosopher’s stone to nutrient recovery and reuse. Chemosphere (2011), doi:10.1016/j.chemosphere.2011.03.001

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Nutrient-Rich Digester Liquor

Treated Digester Liquor

Struvite Precipitation

RECOVERY IMPACTED BY REMOVAL AND BIOSOLIDS PROCESSING

P-Removal Processes • Chemical precipitation and hydroxide

floc adsorption • Enhanced biological phosphorus

removal (EBPR) • Media adsorption/ion exchange

P-Recovery Alternatives • Calcium phosphate precipitation

• Hydroxyapatite [Ca10(PO4)6(OH)2] and others

• Struvite precipitation • MgNH4PO4·6H2O

• Extraction from incinerator ash


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PhoStrip

EBPR Process

PHOSPHORUS WITH EBPR AND ANAEROBIC DIGESTION


Anaerobic Digestion

Dewatering Biosolids

Primary Clarifiers Anaerobic | Oxic Basins

Thickening Particulate P Chemical Precipitation

Release from PAO

Luxury uptake by PAO

PAO in

WAS

Soluble P Particulate P

NH4+

(PO4)3-, Mg2+, K+

Secondary Clarifiers

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Effluent P (0.5 – 1 mg/L)

EBPR AND STRUVITE RECOVERY

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EBPR AND ANAEROBIC DIGESTION

CAUSES

• (PO4)3-, Mg2+ and K+ quickly released by PAOs in WAS. NH4

+ released later during digestion.

CONSEQUENCES

• Struvite formation

• Decreased biosolids dewaterability

Alternatives to prevent these unintended consequences


From Shimp, G.F.; Barnard, J.L.; Bott, C.B. It’s always something. Water Environment & Technology, June 2014, 26(6), 42-47.

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STRUVITE PRECIPITATION

• Mg2+ + NH4+ + (PO4)3- + 6 H2O MgNH4PO4·6 H2O↓

• Mg usually limiting. MgCl2 commonly added. • High pH is favorable. NaOH commonly added.

The root cause of the problem is also part of the answer


Valuable Struvite

Nuisance Struvite

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•Plant-activated release by citric acid from root growth •Low stormwater runoff potential

Struvite Conventional Fertilizers

Typical Composition (N-P2O5-K2O) 5-28-0 10% Mg DAP: 18-46-0

MAP: 11-52-0

Water solubility, g/L 0.2 DAP: 588 MAP: 370

Heavy metal content Low Higher Salt index * 7.7 29, 27 * Butler, G (2013) Struvite as a phosphorus replacement, The Cutting Edge, 451-453

WHY STRUVITE FERTILIZER?


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DURHAM AWWTF – ORIGINAL STRUVITE RECOVERY CONFIGURATION

November 20, 2014

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Sludge Sludge

Fermenter Anaerobic Digestion

Dewatering Centrifuge

Biosolids to Land Application

Primary Clarifiers

Pearl® Struvite Reactor

Activated Sludge EBPR Process

Thickening Centrifuge

Gravity Thickener Tertiary

Chemical Sludge

90% Phosphate Removed

20% Ammonia Removed

Crystal Green®

Slow Release Struvite Fertilizer Pellets 5-28-0 10%Mg

DURHAM AWWTF STRUVITE RECOVERY FACILITIES


Bottom of Reactors

Harvested Pellets

Drier

OutputScreen

SizingScreen

Top of Reactors

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Waste Activated Sludge Stripping to Remove Internal Phosphorus (WASSTRIP®) • More protection

from nuisance struvite deposits

• K+ released with (PO4)3- and Mg2+ shunted around digester

• NH4+ released

during digestion

• MgNH4PO4·6 H2O precipitated

• Studies ongoing to quantify dewatering improvements


(PO4)3- Mg2+ K+

(NH4)+

K+

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5 YEARS OF STRUVITE RECOVERY BY CLEAN WATER SERVICES • Durham AWWTF – 25-mgd ADF, <0.1 mg TP/L May - Oct

• $2.5 million investment • May 2009 - Startup of 3 Pearl 500 struvite recovery units • 2011 – WASSTRIP increased P loading to units by ~80% • May 2012 - Upsized one Pearl 500 to Pearl 2000

• Rock Creek AWWTF – 35-mgd ADF, <0.1 mg TP/L May - Oct

• $4.5 million investment • Fall 2011 - Installed two Pearl 2000 units • Future WASSTRIP planned after fermenters

• 5 to 7 year payback

• 40% less alum usage • 20% less hauled biosolids • 20% less NH3-N recycled • 90% less P recycled • Fertilizer revenue

Pioneering phosphorus recovery in North America


Rock Creek AWWTF Struvite Recovery Facility

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STRUVITE PRECIPITATION ALTERNATIVES

• Ostara Pearl®

• MHI Multiform™

• Kansas Environmental Management Associates (KEMA) Phred™

• Aquatec Crystalactor®

• CNP AirPrex®


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http://www.kemallc.com/Home/products/IMG_1698v2.jpg?attredirects=0

STRUVITE PRODUCT ALTERNATIVES November 20, 2014 SWOWEA Plant Operations Seminar l

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Ostara Crystal Green® Multiform Harvest Fertilizer

KEMA TerraPhos™ AirPrex® MAP fertilizer

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&docid=efqkwR6p6mco9M&tbnid=rAsWPB0K9XpTRM:&ved=0CAUQjRw&url=http://www.ostara.com/content/crystal-green-environmentally-responsible-phosphorus-fertilizer&ei=_GL7U_u4FKi-8QH5t4G4Bw&bvm=bv.73612305,d.b2U&psig=AFQjCNHCFVu7rpr1BaBeR6DcXAtw0fp1gg&ust=1409070134651891

http://www.kemallc.com/Home/products---slow-release-fertilizer/terraphos cropped.JPG?attredirects=0

ALTERNATIVES FOR DIGESTER SLUDGE VS. CENTRATE/FILTRATE

November 20, 2014

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Biosolids dewatering costs drive recovery decision in many applications

Process Flow Diagram of Nine Springs WWTP (Madison Metropolitan Sewer District)

PRE-DIGESTION PHOSPHORUS RELEASE ALTERNATIVES

• WASSTRIP®

• P-stripping with acid/gas phased digestion

• MultiWAS ™


From Barnard J. and Shimp G.; The Impacts of Biological Phosphorus Removal on Biosolids Dewatering; Proceedings of the Water Environment Federation, Nutrient Removal and Recovery 2013.

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GROWTH IN STRUVITE RECOVERY November 20, 2014 SWOWEA Plant Operations Seminar l

• Minimize nuisance deposits

• Reduce P & N recycle loads

• Reduce P content of biosolids

• Improved biosolids dewaterability

• Beneficial recovery of nutrients 22

CHICAGO BREAKING GROUND ON NEW STRUVITE RECOVERY FACILITY

November 20, 2014

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Stickney WRP

• 1.2 BGD design capacity • Effluent TP: 1-2 mg/L

• Effluent TP goal: ≤1 mg/L

• Optimize bio-P removal

• WASSTRIP + struvite recovery

RECOVERY POTENTIAL WITH LOWER EFFLUENT LIMITS

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HOW LOW SHOULD WE GO?

November 20, 2014

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Significant questions remain. Overall sustainability? Trading with nonpoint sources? IJC target = 0.5 mg/L Case-specific evaluations.

From Ohio EPA, Ohio Nutrient Reduction Strategy, June 28, 2013.

GENERAL RULES OF THUMB

Some exceptions to the rules. Case-specific alternative evaluations recommended.


Effluent Concentration

(mg-TP/L) Process Alternatives

0.5 to 1.5

A. Chemical precipitation and floc adsorption

B. EBPR with reliable VFA feed

0.05 to 0.3 A and/or B with effluent filtration

<0.05 Tertiary system

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Water Environment & Technology (Oct 2011)

MOST ULTRALOW ALTERNATIVES RELY ON ALUM OR FERRIC CHEMISTRY

Alum and ferric chemistry interfere with struvite recovery


Alternative Alum or Ferric Other

Chemically enhanced clarification Yes Polishing filter generally required. Lamella settler, solids contact, ballasted flocculation options.

Two-stage granular media filtration Yes

Low-pressure membrane filtration Yes Membrane bioreactor (MBR) or tertiary systems.

Reverse osmosis Yes

Media adsorption / ion exchange No Filter pretreatment generally required

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NEW PHOSPHORUS ADSORPTION TECHNOLOGY • Polymeric metal oxide media

developed by Asahi Kasei Chemicals

• Long-term pilot studies in Japan and Kansas


Fibril

Cavities

Fibril

Cavities

Exterior Surface Cross Section Internal Structure

• 0.13-mgd demonstration at Kasumigaura Lake WWTP (near Tokyo) averaged TP < 0.03 mg/L during first year

• 10-mgd facility on hold, pending ultralow permit limits 28

REMOVAL AND RECOVERY PROCESS

In situ media regeneration and phosphorus recovery


SecondaryEffluent Filter Treated

Water

Solid/liquid separation

pHControl

Tank

ＡＣ

PrecipitationReactor

DesorptionTank

LimeTank

Ｂ AcidTank

CausticTank

AdsorptionTowers

Adsorption

Desorption

Recovery

Neutralization

Carrousel Operation Two columns in series Third column stand-by

Waste

Phosphorus-LadenSolids

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CONCEPT FOR MEDIA ADSORPTION / ION EXCHANGE WITH STRUVITE RECOVERY


Sludge

Anaerobic Digestion

Dewatering Centrifuge

Biosolids

Primary Clarifiers Activated Sludge EBPR

Thickening Centrifuge

Fermenter & Thickener

Struvite Fertilizer

VFA Effluent Filter

Anaerobic Release Tank

Struvite Reactor

Mg2+

(PO4)3-

Mg2+

K+

NH4+

Phosphorus Adsorption

Media

Desorption Fluid

(PO4)3-, OH-

OH-

WASSTRIP®

ASAHI

H+

K+

MgNH4(PO4)·6H2O 30

SUMMARY • The need for phosphorus recovery is growing • Recovery processes commercially available • >5 years of full-scale struvite recovery with EBPR and

anaerobic digestion • If lower effluent TP required:

o Various alternatives to evaluate o New media option doesn’t require alum or ferric Repeatable in-situ regeneration Potential integration with struvite recovery and EBPR

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EXTRAS

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PEARL® INSTALLATIONS November 20, 2014 SWOWEA Plant Operations Seminar l

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Name Location WWTP Capacity Startup Date Gold Bar/Clover Bar (demonstration) Edmonton, AB 80 MGD May-07

Durham AWWTP Tigard, OR 20 MGD May-09

Nansemond WWTP Suffolk, VA 20 MGD May-10

York WWTP York, PA 20 MGD Jun-10

Rock Creek AWWTP Hillsboro, OR 30 MGD Mar-12

Slough STW United Kingdom 15 MGD Dec-12

H.M. Weir WWTP Saskatoon, SK 20 MGD Jan-13

Nine Springs WWTP Madison, WI 40 MGD Jan-14

Truckee Meadows WRF Reno, NV 40 MGD Dec-14

F. Wayne Hill WRC Gwinnett County, GA 50 MGD Jan-15

Gold Bar/Clover Bar Edmonton, AB 80 MGD Mar-15

Stickney WRP Stickney, IL 1,200 MGD Oct-15

Bonnybrook WWTP Calgary, AB 110 MGD Mar-16

Amersfoort Amersfoort, Netherlands 15 MGD Mar-16

AIRPREX® INSTALLATIONS November 20, 2014 SWOWEA Plant Operations Seminar l

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Name Location WWTP Capacity Startup Date

Berlin WWTP Germany 125 mgd 2003

Moenchengladbach WWTP Germany 70 mgd 2007

Reest & Wieden WWTP Holland 31 mgd 2012

Amsterdam WWTP Holland 120 mgd 2014

successful phosphorus removal and recovery phos.pdfnovember 20, 2014 jim fitzpatrick senior process...

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