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19th Annual Specialty Conference November 2, 2012
Ultra-low Phosphorus Removal
C.J. Strain, P.E.
Industry Evolution •The regulatory environment. •The future of phosphorus removal as projected by the
EPA. •Achieving ultra-low phosphorus. •How a retrofit can bring you into compliance. •Recent installations with phosphorus limits below 0.1
mg/L. • Some of the lowest enforced permit levels in the
world.
Forms of Phosphorus in the Water
Total phosphorus •Particulate vs soluble
– 0.54 um
•Organic phosphates and polyphosphates
– DNA, RNA, phospholipids – acid hydrolysable – acid and digestion
•Reactive phosphorus
Dynamic Regulatory Issues EPA requiring all States to establish numeric discharge targets - Section 303(c) of the Clean Water Act • Florida EPA sued to enforce the limits – working with
Florida State regulators. – Natural Resources and Environment, Volume 26, Number 3. – In-stream nutrient criteria of 0.04 mg/L
• Wisconsin DNR is frontrunner with new limits. – Roughly half of 540 municipal plants must hit 0.1 mg/L P. – 0.015-0.04 mg/L for lakes, 0.1 for large rivers, 0.075 for streams – NR 102, 217, 151
• Many other states close behind. – Colorado looking at 0.05 mg/L P for several plants.
• http://epa.gov/nandppolicy/
Phosphorus Removal Technologies
•BNR. •Chemical precipitation. •Coagulation followed by filtration.
– Sand filters – Rotating or cloth disk filters – Fuzzy filters
•Membranes: MBR and tertiary •Adsorption
Adsorptive Phosphorus Removal • Removes virtually all reactive phosporus.
• Higher levels of treatment are readily achieved with:
– series system
– reject recycle
Fe
P
Hydrous ferric oxide-coated sand -Images from scanning electron microscopy X-ray fluorescence
Fe
P
Processes
Media Filters
•Gravity sand filters •Continuous backwash •No moving parts •Water reuse-quality
filtration •CA Title 22 accepted •Blue PRO ® & Blue NITE®
filtration •Patented control systems
Centra-flo® Filters • Fiberglass or
concrete
•5 gpm to multi-MGD projects
6 MGD concrete
2 MGD fiberglass
Reactive Filtration Process or Clarified
Wastewater
Wat
er
Particles
HFO Sand Grain
Fe
Fe
Fe
O
OAs
O
OMe+
• N, S - biological • S, P, Se, Sb, As • Al, Zn, Cd, Hg, Pb, Mn,
Fe, Cr, Cu, Ni, etc.
• Ferric salt chemical vs alum Lower phosphorus Higher efficiency Less chemical Better solids separation Better dewatering
Design Preferences - Chemical
Configuration Ferric Alum Removal Mechanism Adsorption/Coagulation Coagulation Dosage (Tertiary) 5 to 10 mg/L Fe 4 to 8 Me:P Dry chemical - tons/yr 150 to 300 350 to 700 Sludge generated - tons/yr 300 to 600 1,500 to 2,500
Consumed alkalinity – mg/L 15 to 30 35 to 70
• Design Comparison
• Spherical geometry, sub-angular sand minimized • 0.9-0.95 mm spherical sand Greater reliability Higher surface area Less media required (1.5 m vs 2 m)
Design Preferences - Media
Retrofits
Waste Handling • Phosphorus final fate is in waste solids • No changes are required in the waste handling
system • No significant increase in amount of waste
produced or waste disposal costs • Recycling rejects may reduce other chemical use
at some plants • Reject Flow = 4 to 7% per treatment stage
The Reject Factor
Blu
e P
RO
®
Sys
tem
Off
Case Study Hayden WWTP • Performance modeling:
-Ch2MHill formulated modeling plan • Location: Hayden, Idaho - USA • Equipment: Two CF-50 filters in a
series configuration • System Size:
360,000 GPD (1,360 m3/day) • Deliverable: < 0.02 mg/L TP • Installation Complete: 2005 • Performance:
-Averaged <0.02 mg/L -Low of <0.0023 mg/L (detection limit)
• Site participation in industry research
Projects in Design 1. Location: Minnesota Performance: < 1.3 ppt Hg, < 0.02 mg/L P
2. Location: Montana Performance: < 0.005 mg/L Cu, < 0.001
mg/L Pb, < 0.01 mg/L Zn, < 0.01 mg/L P 3. Location: Idaho Performance: dairy to < 0.07 mg/L P
Pilot Study – Lakeshore Water Pollution Control Plant • Performance modeling (2009):
-Black and Veatch proctored pilot • Location: Innisfil, Ontario • Equipment: Two CF-7 filters in
series • System flow:
50,000 GPD (190 m3/day) • Deliverable: < 0.02 mg/L TP • Performance:
Single stage < 0.05 mg/L TP Second stage < 0.02 mg/L TP
• Stress Testing: Diurnal flows Loading to 4.44 L/s/m2 High solids
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
4/20/09 4/25/09 4/30/09 5/5/09 5/10/09 5/15/09
Tota
l Pho
spho
rus
(mg/
L)
1st Pass Effluent 2nd Pass Effluent
Case Study Georgetown WWTP • Location: Georgetown, CO • Engineer: Frachetti
Engineering • System Size:
0.88 MGD average flow, 1.2 MGD peak hr flow
• Deliverable: 0.3 mg/L TP 0.2 mg/L Zinc
• Installation Complete: 2011 • Performance:
0.01 to 0.1 mg/L P 0.08 to 0.2 mg/L Zn
Case Study – Nosoca Pines • Location: South Carolina • Equipment: Two CF-7 filters in series • System Size:
25,000 GPD peak hr flow • Deliverable: 0.06 mg/L TP monthly
average • Installation Complete: 2009 • Performance:
-Averaged <0.02 mg/L -Low of <0.01 mg/L (detection limit)
Case Study – Westerly WWTP • Location: Marlborough, MA • Engineer: CDM Smith • Equipment: twenty-four
model CF-50 filters • System Size:
4.15 MGD average flow, 11.62 MGD peak hr flow
• Deliverable: 0.07 mg/L TP • Installation Complete: 2011 • Performance:
Averaged 0.04 mg/L TP Low of 0.02 mg/L TP < 0.007 mg/L OP
Case Study - Simultaneous P and N Removal
Results from one treatment stage: • PATE Engineers • TP : 3.4 to 0.14 mg/L • Total Nitrates-N: 10.6 to 2.2 mg/L
• Ferric sulfate and glycerin added
Case Study – City of Decatur • Location: Decatur, AR • Engineer: McClelland
Consulting Engineers • 2011 Pilot:
35 gpm pilot • Deliverable: <0.05 mg/L TP • Performance:
Averaged 0.01 mg/L TP In single stage of treatment
Analytical Phosphorus Results Date 2011
Total Phosphorus (mg/L) *Influent 1st Pass 2nd Pass
7/15 0.14 < 0.01 < 0.01 7/18 0.26 < 0.01 7/18 0.15 < 0.01 < 0.01 7/19 0.16 < 0.01 7/19 0.10 < 0.01 < 0.01 7/20 0.14 < 0.01 7/20 0.17 < 0.01 < 0.01 7/21 0.13 < 0.01 7/21 0.11 < 0.01 < 0.01 7/22 0.15 < 0.01 7/22 0.15 0.01 < 0.01 7/25 0.16 < 0.01 7/25 0.20 < 0.01 < 0.01 7/26 0.19 < 0.01 7/26 0.17 < 0.01 < 0.01
Industry Evolution •The regulatory environment and the future of
phosphorus removal as projected by the EPA. •Blue Water’s revolutionary proprietary systems. •How a retrofit can bring you into compliance. •Recent installations with phosphorus limits below 0.1
mg/L. •The plants with the lowest enforced permit levels in
the world.
