improving efficiency of dewatering alternatives to conventional dewatering technologies...
TRANSCRIPT
Improving Efficiency of DewateringAlternatives to Conventional Dewatering
Technologies
Robert Gillette, PE, BCEESteve Swanback, PE
Rebecca Overacre, PE
2009 PNCWA Webinar Recent Developments In
Biosolids Management Processes
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Outline
1. Screw press technologya. Performance survey resultsb. Pilot testing resultsc. Lifecycle cost evaluation (Class A and Class B)d. Design considerations
2. Rotary fan press technologya. Performance survey resultsb. Pilot testing resultsc. Lifecycle cost evaluation (Class A and Class B)d. Design considerations
3. Overview of R&D Technologies
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Screw Press Technology
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Screw Press Manufacturers
• Huber (inclined)
• FKC (horizontal)
Screw Press General Description
Dewatering by Volume Reduction
Screw Press Expanded View
Screw Press Expanded ViewClass A Option
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Flow Schematic
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Tallahassee, FL, FKC InstallationTallahassee, FL, FKC Installation
FKC Screw Press
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FKC Screw Press
Petaluma, CA, FKC InstallationPetaluma, CA, FKC Installation
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Huber Press
Magna, UT, Huber InstallationMagna, UT, Huber Installation
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Huber Press
Maine, Huber InstallationMaine, Huber Installation
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Performance Survey
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Survey of 22 Full Scale Installations –The Cake Solids Concentration Depends on Type of Sludge
Type of Sludge Screw Press Cake (% solids)FKC 15 – 20
FKC (with steam and lime) 20 – 45Huber 12 – 20FKC 21 – 28
WAS
Huber 22 – 25Raw Huber 18 – 40
PS+WASFKC > 18
Huber 19 – 24Aerobically Digested
Anaerobically Digested
FKC 17 – 25Anaerobically Digested Huber 13 – 16
Raw
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Survey of 22 Full Scale Installations –The Median Cleaning Schedule is Once Per Week
Manual Cleaning Schedule(times per month)
0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Facility Number
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Case Study –St Petersburg, FL
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Pilot Results - Projected Full Performance – St. Petersburg
Manufacturers Recommendations
Screw PressBelt Press CentrifugeClass B Class A
Minimum Cake Solids Concentration (% solids)
18 21 16 33
Maximum Polymer Dosage (lb/DT)
19 25 30 33
Minimum Solids Capture (%)
95 95 90 90
Parameter
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“Relative” Cost Comparison
BFP Centrifuge Screw Press
Capital Cost $ $$$ $$
Building Modifications $ $$ $$
Odor Control $$$ $ $
Power $ $$$ $
Maintenance $$ $$ $
Chemical $$ $$$ $$
Hauling $$ $ $$
Disposal $$ $ $$
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Performance Comparison
Will Vary Depending on Conditions!!!Will Vary Depending on Conditions!!!
BFP Centrifuge Screw Press
% Solids Produced ++ +++ +
Filtrate/Centrate Quality ++ ++ +
Reliability ++ ++ +++
Operator Attention Required + ++ +++
Ease of startup and shutdown ++ + ++
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Design Considerations
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Design Considerations
• Lead time (from Japan or Germany): prepurchase?
• Custom design – varying dimensions until shop drawing
• Performance guarantee and penalty for non-compliance
• Basis of design– Loading & capacity: pilot test– Run time, unattended operation
• Effect of rising steel costs – units all SST
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Design Considerations, Continued
• Need headroom if RST on mezzanine• Monorail/overhead crane• Building considerations – footprint
requirement – or outside• Provision for Class A in future• Cake conveyance options affects layout
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Design Parameters
• Range of Capacity: Up to 8.5 DT/day– At “nominal” speed
• RST output (% Solids): around 4%• Screw Press output (% Solids): 15 – 28%• Polymer consumption: 20 – 40 lb/DT• Detention time: approximately 4 hours• Motor speed: as low as 0.3 rpm• Motor HP – largest unit is 7.5 HP
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Rotary Press Technology
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Rotary Press Manufacturers
Fournier
Prime Solutions
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Rotary Press Schematic
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Process Cutaway
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Design Parameters
• Range of Capacity: 7-250 gpm• Cake % Solids: 12 – 28%• Detention time: N/A• Motor speed: as low as 1-3 rpm• Motor HP: 5-20 HP
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Fournier Rotary Press
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• Size Compared to Other Technologies
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Multiple Channels on Single Drive
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Fournier Rotary Press Pilot Test
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Prime Solutions Rotary Fan Press
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Performance Survey
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Survey Results
Facility EquipmentFacility
Size (mgd)
Solids Type Incoming % TS
Discharge % TS
Raiford, FL Prison WWTP
Rotary fan press 1.1 Extended aeration
1.6-2.5 19-22
Front Royal, VAMunicipal WWTP
Rotary fan press 3.3 Thermophilic Anaerobic Digestion
3.5 25
Fairfield, CAMunicipal WWTP
Rotary fan press 15.5 Conventional Anaerobic Digestion
2 17
Lafayette, TNMunicipal WWTP
Rotary press 0.5 Conventional Anaerobic Digestion
1.0-1.5 25
Portland, MEMunicipal WWTP
Rotary press 19.8 Thickened PS/WAS
3-6 19-25
Hampton, NHMunicipal WWTP
Rotary press 2.5 Septage/PS/WAS
6-8 26-28
Murfreesboro, TNMunicipal WWTP
Rotary press 15 PS/WAS 0.8-1 12-14
Scarborough, MEMunicipal WWTP
Rotary press 1.4 Thickened PS/WAS
3 28
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Rotary Dewatering Features
• Low speed, low vibration, low shear• Uses less energy than centrifuges or BFPs• Modular• Small footprint• Minimal start-up and shutdown time• Minimal moving parts• Odors contained
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R&D Technologies
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EKG Technologies
• Electrokinetic Geosynthetics (EKG) Technology– Theory – Electro-osmotic principle
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Uses of EKG Technology
• Ashbrook Product– Anaerobically/Aerobically Digested
Sludge• Fresno• England
– Alternative to conventional dewatering
• Siemen’s Product– Secondary dewatering process– Alternative to sludge drying
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Siemen’s ELODE Technology
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Siemen’s ELODE Technology
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Siemen’s ELODE Technology
