Post on 26-Apr-2018
transcript
Slide 1
Treating Cyanotoxins with Granular Activated Carbon
Kendra RyanCalgon Carbon Corporation
Municipal Applications Engineer
Ralph Franco PECalgon Carbon Corporation
Director – Municipal Products
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• Background – Algae: Cyanotoxin Compounds‒ Formation Conditions‒ Most Common Cyanotoxins‒ Treatment Approaches
• Activated Carbon‒ Adsorption & Starting Material Basics‒ Activated Carbon in Water Treatment - PAC & GAC‒ Performance Studies
Presentation Overview
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Algae & Cyanotoxins
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• Naturally occurring organisms• Thrive under certain conditions:‒ Sunlight‒ Warm temperatures‒ Slow Moving Water (i.e. Lakes/Reservoirs)‒ Excess nutrients Nitrogen Phosphorous Potassium
• Harmful Algal Blooms (HABs) ‒ Typical season duration = 3 months‒ Promote growth of cyanobacteria
Algae Formation
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Satellite Image of Blue-Green Algal Outbreak on Lake Erie, 2011
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• By-product of cyanobacteria life cycle‒ Over 3,000 known species
• 2 primary classes:‒ Hepatotoxin – affecting the liver‒ Neurotoxin – affecting nerves & nervous system
• 4 primary toxins of interest:‒ Anatoxin-A‒ Cylindrospermopsin‒ Microcystin-LR‒ Saxitoxin
Cyanotoxins
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• Shut-off intake‒ Sufficient Warning‒ Multiple source water options
• Treatment Approaches‒ Adsorption via Powder Activated Carbon‒ Adjustment of Pretreatment chemistry‒ Ozone Oxidation‒ Adsorption via Granular Activated Carbon‒ Reverse Osmosis (RO)‒ UV Advanced Oxidation (UV/AOP)‒ Adjustment of oxidant levels
Operational Options
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Introduction to Activated Carbon
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Structure of Activated Carbon
• Carbon is the base element of graphite
AC is 99%
graphite
• Imperfections result in porosity and greater surface area
AC is a crude
form of graphite
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Bituminous CoalCoconut Shell
Sub-BituminousLignitePeatWood
Starting Materials
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Starting Materials
• Ash impurities• Density• Hardness• Transport pore structure• Adsorption kinetics
Raw material dictates all of the product possibilities
≠
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Manufacturing Processes
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Direct Reagglomerated
Over activation in the outer Part of the granule
Low Activation Even Activation
Granular Activated CarbonProduct differences: Re-agglomeration versus Direct Activation
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Granular Activated Carbon
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Where is it Used?
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Where is it Used?
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Where is it Used?
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Disinfection Byproducts (DBPs)•Trihalomethanes
(THMs)•Haloacetic Acids
(HAA5s)
Carcinogenic VOCs•TCE•PCE
Perfluorinated Compounds (PFCs)•PFOA•PFOS
Algal Toxins•Microcystin•Cylindros-
permopsin•Anatoxin A
Pesticides•1,2,3 –
Trichloropropane (1,2,3-TCP)
•Dieldrin•Glyphosate
EDCs & PCPPs•Medicine•Pharmaceuticals
Defense Barrier•Chemical Spills
Simultaneous Contaminant RemovalUSEPA considers GAC to be an effective treatment technology for:
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Economic Benefit of GAC
The average family of 4 consumes 65,700 gallons of water annually
Tap water filtered by GAC costs a family of 4 roughly $2.00/Month (per
AWWA)
The average 2015 price for bottled water is $1.22/gallon
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Performance Testing
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Importance of Testing•Many factors influence the effective service life of GAC
•Temperature•pH•EBCT•Concentration•Competitive Adsorption
•Extremely difficult to quantify without testing
Why
• Feasibility• Product Comparison• Service Life Estimation• Treatment Technology Comparison
Goals
•Bench Scale•TACTIC•Isotherm •ACT/RSSCT
•In-Process•Pilot Column
Types
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Equilibrium batch carbon adsorption tests‒Series of carbon dosages allowed to equilibrate
INCREASING DOSE OF CARBON
Isotherm
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Accelerated Column Test (ACT)
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•fluctuations in influent•flow rate•pH•bio activity•temperature•TSS•physical filtration•backwashable
Incorporates
Pilot Column
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Removal Case Studies
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Ohio EPA Monitoring Website
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• Surface Water Upstream of GAC contactors
• NOM/TOC present Average feed = 2.1 mg/L
• Spiked with cyanotoxins Anatoxin-A feed = 86 µg/L Cylindrospermopsin feed = 45 µg/L Microcystin-LR feed = 55 µg/L
• Contact Time (EBCT) 7 minutes
Cyanotoxin Case Study #1
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• Filtrasorb 300‒ Reagglomerated bituminous coal‒ 8x30 mesh‒ 900 mg/g Iodine Number‒ Virgin
Cyanotoxin Case Study #1
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Cyanotoxin Case Study #1 – Anatoxin-A
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TOC
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Bed Volumes Treated (BV)
TOC and Microcystin-LR vs Bed Volumes Treated
TOC TOC Feed MC-LR MC-LR Feed
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Cyanotoxin Case Study #1 – Cylindrospermopsin
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TOC
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TOC and Cylindrospermopsin vs Bed Volumes Treated
TOC TOC Feed CYN CYN Feed
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Cyanotoxin Case Study #1 – Microcystin-LR
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TOC and Anatoxin-a vs Bed Volumes Treated
TOC TOC Feed ANTX-a ANTX-a Feed
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• 676 days simulated‒ ~245 million gallons water
• Cyanotoxin breakthrough ‒ Initial breakthrough = 52 days‒ 50-70% breakthrough at conclusion
• TOC breakthrough‒ ~60% breakthrough at first cyanotoxin detection
Cyanotoxin Case Study #1
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• Surface Water Upstream of GAC contactors
• NOM/TOC present Average feed = 2.1 mg/L
• Spiked with cyanotoxins Anatoxin-A feed = 86 µg/L Cylindrospermopsin feed = 45 µg/L Microcystin-LR feed = 55 µg/L
• Contact Time (EBCT) 15 minutes
Cyanotoxin Case Study #2
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• Filtrasorb 400‒ Reagglomerated bituminous coal‒ 12x40 mesh‒ 1,000 mg/g Iodine Number‒ Virgin and reactivated GAC
Cyanotoxin Case Study #2
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Cyanotoxin Case Study #2 – Anatoxin-A
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TOC
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Simulated Days of Operation
TOC and Anatoxin-a vs Simulated Days
F-400 TOC CMR F-400 TOC F-400 Feed ANTX-a F-400 ANTX-a CMR F-400 ANTX-a
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Cyanotoxin Case Study #2 – Cylindrospermopsin
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Simulated Days of Operation
TOC and Cylindrospermopsin vs Simulated Days
F-400 TOC CMR F-400 TOC Feed TOC Feed Cyn F-400 Cyn CMR F-400 Cyn
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Cyanotoxin Case Study #2 – Microcystin-LR
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Simulated Days of Operation
TOC and Microcystin-LR vs Simulated Days
CMR F-400 TOC F-400 TOC Feed TOC Feed MC-LR F-400 MC-LR CMR F-400 MC-LR
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Cyanotoxin Case Study #2 – THM Formation
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THMFP vs Simulated Days
F-400 THMFP CMR F-400 THMFP
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• 230 days simulated‒ ~53 million gallons water
• No Cyanotoxin breakthrough ‒ Virgin & reactivated GACs‒ Anatoxin-A detection limit = 0.6 µg/L ‒ Cylindrospermopsin detection limit = 0.03 µg/L ‒ Microcystin-LR detection limit = 0.15 µg/L
• TOC breakthrough‒ Virgin = 74% of influent‒ React = 82% of influent
Cyanotoxin Case Study #2
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• Reagglomerated bituminous coal GAC can be an effective barrier against Anatoxin-A, Cylindrospermopsin, and Microcystin-LR.‒ Both virgin and reactivated‒ Non-detect longer than HAB season‒ Still effective near end of GAC service life for TOC removal/DBP
prevention
Conclusion
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Summary
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• Activated Carbon can be an effective tool for the treatment of Cyanotoxins
• Its important to properly maintain your GAC filters to assure that proper treatment can be obtained during a Harmful Algal Bloom
• Not all Carbons are the same; there are benefits to pilot testing with your specific water to determine the best carbon for your application
Final Takeaways
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Thank you for your time.
Questions?
Ralph Franco PEDirector – Municipal ProductsP: 412-787-6620E: rfranco@calgoncarbon.com