WRF Webcast. Treatment Approaches for Managing Dissolved and Intracellular Cyanotoxins

Transcription

1 No part of this presentation may be copied, reproduced, or otherwise utilized without permission. WRF Webcast Treatment Approaches for Managing Dissolved and Intracellular Cyanotoxins Tuesday, August 22, pm ET (12pm PT)

2 Cyanotoxin Webcast Series

3 WRF Focus Area Cyanobacterial Blooms and Cyanotoxins: Monitoring, Control, and Communication Strategies 1. Source water monitoring strategies 2. Robust analytical methods 3. Cost-effective control options 4. Public outreach and communication strategies and tools

4 Today s Speakers Benjamin D. Stanford, PhD Senior Director, Research and Development American Water Eric C. Wert, PhD, PE Project Manager Applied Water Quality Research Southern Nevada Water Authority

5 Managing Harmful Algal Blooms: Treatment Techniques for Cyanotoxins Benjamin D. Stanford, PhD Senior Director, Research and Development American Water

6 Guidance to Utilities Back to the Basics

7

8 Treatment Plant Management: Removal by Physical-Chemical Processes Effective with Activated Carbon, High Pressure Membranes, and Biofiltration From Adams, C. (2013) Tailored Treatment of Cyanotoxins and Cyanobacteria: Oxidation, Adsorption and Other Technologies, WQTC 2013 Workshop

9 Treatment Plant Management: Removal by Disinfection and/or Oxidation Processes Varies by Type and Water Quality Process Free chlorine Microcystin Moderate (f(ph)) Extracellular Cyanotoxins Cylindrospermopsin Anatoxin A Saxitoxin Effective No, slow Effective Permanganate Effective No Moderate No Monochloramine Slow/no oxidation No No?? Ozone Effective Effective Effective No Chlorine dioxide Slow/no oxidation No No?? AOP Effective Effective Effective?? UV No No???? Adams, C. (2013) Tailored Treatment of Cyanotoxins and Cyanobacteria: Oxidation, Adsorption and Other Technologies, Water Quality Technology Conference Workshop, Long Beach, CA, USA. (November 19, 2013)

10 Considerations for Removal at the Water Treatment Plant

11 Treatment Strategies Depend on Dominance of Intracellular vs. Extracellular Toxins Cells are removed on filters within the treatment plant Extr a Cyanotoxins entering a treatment plant may be: Extracellular Outside the cyanobacterial cells in solution Intracellular Within cyanobacterial cells Cells can leak or lyse upon oxidation, freezing, ultrasonics, etc. Oxidant, Freezing, Energy E Extra Intra Released Extracellular toxin

12 Powdered Activated Carbon (PAC) Can Be Used to Removed Dissolved (Extracellular) Cyanotoxins at the Head of the Plant Typical PAC Addition PAC Removal Monitor toxins Intake Rapid Mix Floc/ Sedimentation Filtration Chlorine contact Distribution PAC selection and optimization Interactions with oxidants Typical 2 to 4 hours

13 Powdered Activated Carbon (PAC treatment) PAC performance is specific to cyanotoxin type and water chemistry Same dose, different removal PAC needs to be evaluated for impacts on performance prior to implementation

14 Biofiltration Can Provide Additional Removal Influent Effluent Biologically active sand filters

15 Granular Activated Carbon (GAC treatment) Provides Post-Filter Adsorption Monitor toxins Intake Rapid Mix Floc/ Sedimentation GACcapped Filtration Chlorine contact Distribution Capped filters possible, but post-filter contactors preferred Two stages of GAC performance Fresh GAC Adsorption Frequent replacement Mature GAC filter Biofiltration Varied and/or partial toxin removal e.g., Treatability of Algal Toxins using Oxidation, Adsorption and Membrane Technologies (WRF project 2839)

16 GAC Provides Post-Filter Adsorption For Cyanotoxins, But Must Be Replaced/Regenerated to Maintain Capacity

17 This Matrix Provides a Reminder of Potential Removal Mechanisms Adapted from C. Adams (2013) Tailored Treatment of Cyanotoxins and Cyanobacteria: Oxidation, Adsorption and Other Technologies, WQTC 2013 Workshop

18 For Most Facilities, Oxidation Is Process Free chlorine The Primary Barrier Microcystin Moderate (f(ph)) Extracellular Cyanotoxins Cylindrospermopsin Anatoxin A Saxitoxin Effective No, slow Effective Permanganate Effective No Moderate No Monochloramine Slow/no oxidation No No?? Ozone Effective Effective Effective No Chlorine dioxide Slow/no oxidation No No?? AOP Effective Effective Effective?? UV No No???? Adams, C. (2013) Tailored Treatment of Cyanotoxins and Cyanobacteria: Oxidation, Adsorption and Other Technologies, Water Quality Technology Conference Workshop, Long Beach, CA, USA. (November 19, 2013)

19 Spreadsheets and Protocols Developed to Help Utilities Plan for and Respond to Events Oxidation Hazen Adams CyanoTOX Calculator for prediction oxidative removal of extracellular toxins Protocol for applying CyanoTOX Sorption AWWA PAC Calculator for Cyanotoxin Removal Protocol for applying PAC Calculator All are downloadable for free from

20 Hazen-Adams CyanoTOX Model Provides Predictive Calculation of Oxidation Impacts on Extracellular Cyanotoxins

21 Either C*T or Oxidant Exposure (Kinetics) Can Be Used In CyanoTOX, CT can be determined: 1. By entering Oxidant dose Instantaneous oxidant demand (immediately subtracted from dose) Oxidant decay rate (entered as a halflife (min)) Contact time 2. (Conservatively) by entering the residual oxidant concentration at the end of contact time; i.e. CT = C residual t contact 3. By directly entering the plant CT

22 Model Outputs Results are based on oxidant decay model and CT or oxidant dose and demand information Tabular and Graphical Results Provided

23 Output : Graphical Dose Decay Worksheet Baffling Factor 0.38 Oxidant Dose (mg/l) 2.5 Instantaneous oxidant demand (mg/l) 1 Contact Time (i.e., hydraulic detent. time, min) 10 Effective Oxidant Half Life (min) 120 (Enter a value in minutes OR "ND" for No Decay") Toxin Concentration (µg/l) Toxin Percent Remaining Figure 2a Microcystin-LR (MC-LR) concentration with Free Chlorine exposure versus Eff. CT Figure 2b Microcystin-LR (MC-LR) percen remaining with Free Chlorine exposure versus Eff. CT Both Ideal removal curve and baffled curves are shown, along with data for plant CT Oxidant conc and CT achieved as a function of time are also plotted. Oxidant Conc. (mg/l) Toxin Percent Removal Eff. CT (mg min / L) Minutes Minutes CT (mg mn / L) Figure 2c Microcystin-LR (MC-LR) percen removal with Free Chlorine exposure versus Eff. CT Minutes Figures 3d and 3e Free Chlorine decay as function of time through p and CT as function of time

24 CyanoTOX (v2.0) Includes 95% CI to Indicate Possible Difference in Observed Rate Due to ELISA vs LC-MS/MS Co-Funded by Water Research Foundation and AWWA

25 CyanoTOX v2.0 Has Expanded ph Range Version 1.0 has ph range from 6 to 9. Utilities requested higher ph values. Version 2.0 has ph range from 6 to 10. Most studies justify expansion to ph 10. Confirming if any exceptions needed (toxin/oxidant combinations)

26 MC Variants Updated individual rate constants for MC variants are now available. Included in CyanoTOX (Version 1). MC-LR with accuracy and the ability to include MC congeners for all oxidants Included in CyanoTOX (Version 2). Relative rate constants for MC (% of MC-LR) with selected congeners and oxidants (e.g., chlorine) slower: MC-LA and LF Faster: MC-RR, -YR and -LY Percentage rates included in model User can modify Allows better prediction for mixtures of MC six congeners

27 What approach for water utilities? Understand your treatment processes SOPs need to be in place at treatment plants with respect how to respond when cyanotoxins are detected and present Unique to individual water treatment plants (treatment options, source water, season, etc.) Unique to individual cyanotoxins Understand your source Monitoring of cyanotoxins (and cyanobacteria) is a key Where to monitor? Source water, influent stream? How to monitor? ELISA, LC/MS/MS, other? On-line? Lab? When to monitor? Continuous, periodic (frequency)?

28 What approach for water utilities? Different treatments likely for different cyanotoxins, and water quality conditions Preoxidation, if used, must be used carefully Released toxins need to be oxidized downstream or upon release (e.g., sufficient oxidant dose, etc.) SOPs may have different short- vs long-term approaches (e.g., oxidation or PAC for short term, followed by biodegradation for chronic (months) of toxins) Develop communications plans and material before an event occurs

29 The Balancing Act: Utilities Must Always Consider Unintended Consequences Treatment and Budget Regulation/ Compliance/ Public Perception

30 Treatment of Intracellular Cyanotoxins Eric C. Wert, PhD, PE Project Manager Applied Water Quality Research Southern Nevada Water Authority

31 Treatment of Intracellular Cyanotoxins toxin toxin Intracellular Cyanobacterial cell Extracellular toxin toxin

32 EPA Health Advisories 10-day drinking water health advisories approach method reporting limits Microcystins: 0.3 μg/l (young children); 1.6 μg/l Cylindrospermopsin: 0.7 μg/l (young children); 3.0 μg/l Release of intracellular toxin is important in water treatment

33 Source Water Monitoring Focus often on extracellular toxins Complete risk assessment should include intracellular toxins Requires total cyanotoxin measurement Intracellular = Total - Extracellular Extraction methods Many mentioned in literature No Standard Method

34 Freeze/thaw Cell Lysis Methods Sonication Microwave Chemical lysis

35 Differences in extraction methods Membrane damage/ Oxidative stress toxin toxin toxin toxin Chemical lysis toxin toxin toxin toxin Cell fragmentation toxin toxin Freeze/thaw Sonication toxin toxin What guidance is provided to water utilities regarding treatment of intracellular cyanotoxins? Ref: Rosen, B.H., et. al., 2010, U.S. Geological Survey Open-File Report

36 Treatment of Intracellular Cyanotoxins agersguidetocyanotoxins.pdf

37 Consensus Guidance Manual Recommendations 1. Switch source water supplies to minimize cyanobacteria cells entering intake 2. Remove cyanobacteria cells using conventional treatment processes Coagulation, sedimentation, flotation are very effective (~95%)

38 How solids and supernatant are handled matters! Optimizing conventional treatment for the removal of cyanobacteria and toxins Water Research Foundation Project #4315 Management of treatment sludge impacted by cyanobacteria Water Research Foundation Project # % cell removal unlikely through conventional coagulation Cells can remain viable, may multiply in sludge for 2-3 weeks Toxin release can be up to 5x initial concentration Risk associated with supernatant return higher than previously assumed Pestana, C. J., et.al. (2016). Science of the Total Environment 565: DOI: /j.scitotenv Dreyfus, J., et. al. (2016) Journal of Water Supply: and Technology - AQUA. 65(6) DOI: /aqua Research

39 Consensus Guidance Manual Recommendations 1. Switch source water supplies to minimize cyanobacteria cells entering intake 2. Remove cyanobacteria cells using conventional treatment processes Coagulation, sedimentation, flotation are very effective (~95%) 3. Avoid or minimize the use of oxidants* to prevent intracellular release

40 Preoxidation is Common in Drinking Water Treatment Disinfection Control of Invasive Species (i.e. zebra/quagga mussel) Biofilm Control on Intake Pipelines Inorganic Contaminants Iron/Manganese Organic Contaminants Taste and Odor Compounds Micropollutants Turning off preoxidant is not always an option

41 Expanding research on the release of intracellular (or cell-bound) metabolites during oxidation process in drinking water treatment Chlorine Ozone Copper Sulfate Chlorine Dioxide Chloramine toxin toxin toxin toxin toxin Hydrogen Peroxide Permanganate

42 WRF Project #4406 Tailored Collaboration Project ( ) Southern Nevada Water Authority University of Colorado at Boulder Fluid Imaging Technologies 3 Primary Focus Areas Cyanobacteria Cell Integrity Release of Metabolites (i.e. cyanotoxins, taste/odor compounds) Release of Disinfection Byproduct Precursors

43 A LOT of Variables! Cyanobacteria Selection and Purification Laboratory Cultured versus Naturally Occurring Cells Isolated Cells versus Mixtures of Cells Finding toxin producing cultures to work with? Morphology Microcystis aeruginosa (microcystin-lr) Growth Phase Oscillatoria sp. (MIB, Geosmin) Lyngbya sp. (Geosmin) 0 Days 12 Days 18 Days 28 Days

44 Assessing Cell Damage Chlorophyll-a Digital Flow Cytometry (FlowCAM) Scanning Electron Microscopy (SEM) Ref: Coral, et. al. (2013) Cell staining Ref: Coral, et. al. (2013)

45 Assessing Intracellular Release Analytical Methods Total/Intracellular toxin extraction Extracellular toxin measurement (ELISA, LC-MS) Release of Metabolites Cyanotoxins, Taste and Odor Compounds Release of Cell-Bound Organic Matter Source of Chlorinous or Nitrogenous DBPs

46 WRF Project #4406 (3) Laboratory Cultured Strains of Cyanobacteria Microcystis aeruginosa, Oscillatoria, Lyngbya (4) Oxidants were evaluated Ozone, Chlorine, Chlorine Dioxide and Chloramine Wide range of oxidant exposures (i.e. concentration over time) Measured Cell Damage using Chlorophyll and Flow Cytometry (FlowCAM) Measured Microcystin Release using LC-MS/MS

47 Effect of Morphology on Cell Damage Chlorophyll-a Degradation (C/Co) MA OSC LYN Chlorine Dose (mg/l) Morphology played a role in the extent of cell damage Empty cells remain with intact cell walls and damaged interior contents DOC release was minimal <0.2 mg/l

48 Morphology plays a role during cell damage Consider exposed surface area Ref: Wert, E.C., et al., Water Research (2013)

49 Microcystin Release Minimal MC-LR release occurred with 50,000 cells/ml MC-LR with 200,000 cells/ml Majority of release occurred at dosages < 0.63 mg/l Oxidation followed published kinetic information 24 hours of contact time High CT Values Chlorine Dioxide MC-LR (µg/l) O3 FCl2 ClO2 NH2Cl (b) 200,000 cells/ml Oxidant Dose (mg/l)

50 Oxidation of Naturally Occurring Microcystis Colonies A [Cl 2 ] 0 :DOC 0 ratio of 0.30 (t = 20 min) was found to completely release intracellular MC-LR With further verification, may be used as an indicator of intracellular toxin release when treating naturally occurring Microcystis Develop Release and Treat Guidance Ref: He and Wert, Water Research (2016)

51 Intracellular release doesn t stop when oxidation is done Cl 2 Intracellular release may occur hours after low exposures Stagnation time typically not addressing in methods of other papers (Another variable!) Important to full-scale systems that may retain damaged cells on downstream processes (i.e. filter surface) Ref: Zhang, H., et. al., Chemosphere (2017)

52 WRF Project #4692 Tailored Collaboration Project ( ) Southern Nevada Water Authority Ecole Polytechnique Montreal Saint Louis University Hazen and Sawyer 3 Primary Focus Areas Evaluate immediate and delayed release at lower oxidant exposures Refine conceptual models Refine guidance to utilities regarding intracellular release

53 Ongoing work will focus on preoxidation and stagnation (WRF Project #4692) Preoxidation doses Additional preoxidant MnO 4 - MC-LR (µg/l) O3 FCl2 ClO2 NH2Cl Reservoir treatment chems Cu 2+ H 2 O 2 Lab-cultured and natural cells ,000 cells/ml Oxidant Dose (mg/l) Ref: Wert, E.C., et al., Water Research (2014) Stagnation times Up to 168 h (filter run time) had previously quenched/filtered after 24 h

54 Summary A LOT of variables involved with intracellular release!!!! Existing research suggests that cyanotoxins are released with low oxidant exposures Little evidence of cell fragmentation during oxidation processes Future research will develop Release and Treat Guidance Normalized conditions CT values Oxidant:DOC ratios resulting in release

55 Acknowledgements Water Research Foundation 4406 Project Team Project Manager: Djanette Khiari Fernando Rosario-Ortiz University of Colorado at Boulder Harry Nelson Fluid Imaging Technologies Water Research Foundation 4692 Project Team Project Manager: Djanette Khiari Katherine Greenstein Southern Nevada Water Authority Arash Zamyadi Ecole de Polytechnique Montreal Craig Adams Saint Louis University Erik Rosenfeldt Hazen and Sawyer Ben Stanford American Water

56 Intracellular/Extracellular Cyanotoxins Effect of Morphology Microcystis Colony Degradation Eric Wert, Ph.D., P.E.

57 Qs - = -.. A Water Utility Manager's Guide to Cyanotoxins Release of Intracellular Metabolites from Cyanobacteria During Oxidation Processes Alternative and Innovative Methods for Source Water Management of Algae and Cyanobacteria 2017 Water Research Foundation.. ALL RJGH1'5 RIGHTS RESERVED.

58 Ongoing WRF Projects Performance Evaluation of ELISA Methods for the Analysis of Cyanotoxins CyanoTOX Field Validation and Enhancement Related to Chemical Kinetics and ELISA Kinetics Release of Intracellular Cyanotoxins during Oxidation of Naturally Occurring and Lab Cultured Cyanobacteria Development of a Risk Communication Toolkit for Cyanotoxins Benthic Cyanobacterial Risk

59 RFP # 4716 Refinement and Standardization of Cyanotoxin Analytical Techniques for Drinking Water Objective: evaluate existing chemical and biological methods for the analysis of cyanotoxins at low part-per-trillion (ppt) detection levels in raw and finished drinking water Proposals due date : 11/1/2017

60 Acknowledgements The development of Hazen-Adams CyanoTOX program was funded by the American Water Works Association with updates co-funded by WaterRF Hazen and Sawyer, Utah State University, St. Louis University, Southern Nevada Water Authority AWWA Cyanotoxin workgroup Craig Adams (SLU), Bob Raczko (United Water), Keith Cartnick (United Water), and Erik Rosenfeldt & Elisa Arevalo (Hazen and Sawyer), Steve Via & Adam Carpenter (AWWA)

61 Q&A

62 Thank You Comments or questions, please contact: For more information visit: