Treating Cyanotoxins with Granular Activated Carbon

Transcription

1 Treating Cyanotoxins with Granular Activated Carbon Ralph Franco PE Calgon Carbon Corporation Director Municipal Products Kendra Ryan Calgon Carbon Corporation Municipal Applications Engineer Slide 1

2 Presentation Overview 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 Slide 2

3 Algae & Cyanotoxins Slide 3

4 Algae Formation 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 Slide 4

5 Satellite Image of Blue-Green Algal Outbreak on Lake Erie, 2011 Slide 5

6 Slide 6

7 Cyanotoxins 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 Slide 7

8 Operational Options 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 Slide 8

9 Introduction to Activated Carbon Slide 9

10 Structure of Activated Carbon AC is 99% graphite Carbon is the base element of graphite AC is a crude form of graphite Imperfections result in porosity and greater surface area Slide 10

11 Starting Materials Bituminous Coal Coconut Shell Sub-Bituminous Lignite Peat Wood Slide 11

12 Starting Materials Raw material dictates all of the product possibilities Ash impurities Density Hardness Transport pore structure Adsorption kinetics Slide 12

13 Manufacturing Processes Slide 13

14 Granular Activated Carbon Product differences: Re-agglomeration versus Direct Activation Low Activation Even Activation Direct Reagglomerated Over activation in the outer Part of the granule Slide 14

15 Granular Activated Carbon Slide 15

16 Where is it Used? Slide 16

17 Where is it Used? Slide 17

18 Where is it Used? Slide 18

19 Simultaneous Contaminant Removal USEPA considers GAC to be an effective treatment technology for: Algal Toxins Microcystin Cylindrospermopsin Anatoxin A Carcinogenic VOCs TCE PCE Disinfection Byproducts (DBPs) Trihalomethanes (THMs) Haloacetic Acids (HAA5s) Perfluorinated Compounds (PFCs) PFOA PFOS Pesticides 1,2,3 Trichloropropane (1,2,3-TCP) Dieldrin Glyphosate EDCs & PCPPs Medicine Pharmaceuticals Defense Barrier Chemical Spills Slide 19

20 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 Slide 20

21 Performance Testing Slide 21

22 Importance of Testing Why Many factors influence the effective service life of GAC Temperature ph EBCT Concentration Competitive Adsorption Extremely difficult to quantify without testing Goals Types Feasibility Product Comparison Service Life Estimation Treatment Technology Comparison Bench Scale TACTIC Isotherm ACT/RSSCT In-Process Pilot Column Slide 22

23 Isotherm Equilibrium batch carbon adsorption tests Series of carbon dosages allowed to equilibrate INCREASING DOSE OF CARBON Slide 23

24 Accelerated Column Test (ACT) Slide 24

25 Pilot Column Incorporates fluctuations in influent flow rate ph bio activity temperature TSS physical filtration backwashable Slide 25

26 Removal Case Studies Slide 26

27 Ohio EPA Monitoring Website Slide 27

28 Cyanotoxin Case Study #1 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 Slide 28

29 Cyanotoxin Case Study #1 Filtrasorb 300 Reagglomerated bituminous coal 8x30 mesh 900 mg/g Iodine Number Virgin Slide 29

30 Cyanotoxin Case Study #1 Anatoxin-A 3 TOC and Microcystin-LR vs Bed Volumes Treated 70 TOC Concentration (ppm) Microcystin-LR Concentration (ppb) ,000 40,000 60,000 80, , , ,000 Bed Volumes Treated (BV) TOC TOC Feed MC-LR MC-LR Feed Slide 30

31 Cyanotoxin Case Study #1 Cylindrospermopsin TOC Concentration (ppm) TOC and Cylindrospermopsin vs Bed Volumes Treated Bed Volumes Treated (BV) TOC TOC Feed CYN CYN Feed Cylindrospermopsin Concentration (ppb) Slide 31

32 Cyanotoxin Case Study #1 Microcystin-LR 3 TOC and Anatoxin-a vs Bed Volumes Treated 30 TOC Concentration (ppm) Anatoxin-a Concentration (ppb) Bed Volumes Treated (BV) TOC TOC Feed ANTX-a ANTX-a Feed Slide 32

33 Cyanotoxin Case Study #1 676 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 Slide 33

34 Cyanotoxin Case Study #2 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 Slide 34

35 Cyanotoxin Case Study #2 Filtrasorb 400 Reagglomerated bituminous coal 12x40 mesh 1,000 mg/g Iodine Number Virgin and reactivated GAC Slide 35

36 Cyanotoxin Case Study #2 Anatoxin-A 2.5 TOC and Anatoxin-a vs Simulated Days 120 TOC Concentration (ppm) Anatoxin-a (ppb) Simulated Days of Operation F-400 TOC CMR F-400 TOC F-400 Feed ANTX-a F-400 ANTX-a CMR F-400 ANTX-a Slide 36

37 Cyanotoxin Case Study #2 Cylindrospermopsin 2.5 TOC and Cylindrospermopsin vs Simulated Days 50 TOC Concentration (ppm) Cylindrospermopsin (ppb) Simulated Days of Operation F-400 TOC CMR F-400 TOC Feed TOC Feed Cyn F-400 Cyn CMR F-400 Cyn Slide 37

38 Cyanotoxin Case Study #2 Microcystin-LR 2.5 TOC and Microcystin-LR vs Simulated Days 70 TOC Concentration (ppm) Microcystin-LR (ppb) Simulated Days of Operation CMR F-400 TOC F-400 TOC Feed TOC Feed MC-LR F-400 MC-LR CMR F-400 MC-LR Slide 38

39 Cyanotoxin Case Study #2 THM Formation 100 THMFP vs Simulated Days THMFP (ppb) Simulated Days of Operation F-400 THMFP CMR F-400 THMFP Slide 39

40 Cyanotoxin Case Study #2 230 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 Slide 40

41 Conclusion 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 Slide 41

42 Summary Slide 42

43 Final Takeaways 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 Slide 43

44 Thank you for your time. Questions? Ralph Franco PE Director Municipal Products P: E: Slide 44