Cyanobacteria & Cyanotoxins Utility Case Studies and Management Strategies for this Emerging Concern

Transcription

1 Cyanobacteria & Cyanotoxins Utility Case Studies and Management Strategies for this Emerging Concern AWWA NY Section Conference April 12-14, 2016 Saratoga Springs, NY Keith W. Cartnick SUEZ Water Fred S. Lubnow, Ph.D. Princeton Hydro, LLC

2 What are Algae? Most are microscopic, photosynthetic organisms More of an ecological term than taxonomic Base of the aquatic food web; many algae are necessary and good However, some algae, particularly the blue-green algae (cyanobacteria) are a nuisance (surface scums, taste and odor, cyanotoxins)

3 Diversity of Freshwater Algae

4 What Do Cyanobacteria Need to Grow? Light / Temperature / Carbon Dioxide Macro-Nutrients (Nitrogen, Phosphorus) Micro-Nutrients (Iron, Silica, others) For most Mid-Atlantic freshwater systems, phosphorus is the primary limiting nutrient 1 lbs of phosphorus has the potential to generate up to 1,100 lbs of wet algae biomass More phosphorus means more algae

5 Where is the phosphorus coming from?

6 Nuisance Freshwater Algae Planktonic Bloom Filamentous Mat Algae

7 Cyanobacteria (blue-green algae) Actually are photosynthetic bacteria The dominant nuisance group freshwater ecosystems Responsible for nuisance scums, impact on recreational usage, potable water supplies Can produce taste and odor compounds (geosmin / MIB) and cyanotoxins. Many are not grazed by zooplankton Excellent Oregon reference site:

8 Managing Algae & Cyanobacteria and Controlling Toxins Understand water supply hydrology and ecology Monitoring, Triggers and management protocols Controlling algae and cyanobacteria in water supply (passive and active management) Intake options Pretreatment options Treatment process objectives (avoid unintended consequences) Alternate water sources Raw Water RM F S GF CW HSP Distribution System 43

9 SUEZ (United Water) Approach

10 Monitoring, Management and Treatment Plan (MMT Plan) Monitoring Collect site-specific data in the reservoir to assess and respond to conditions Management Implementation of both in-lake and watershed-based measures to improve overall water quality. Utilize alternate sources, if possible and if necessary. Treatment Develop more of a pro-active than reactive treatment strategy for the reservoir. Implement control measures at the WTP.

11 Monitoring Indicators and Triggers Monitoring and response strategies will be system-specific Indicators are an important tool Selected parameters Frequent monitoring Monitoring location, timing, and frequency must balance competing objectives Practical within utility staffing and operating constraints Provide actionable information What might result from a trigger? Increased monitoring Monitoring of additional parameters Increasing coordination with other water suppliers Modification of withdrawal Modification of treatment 45

12 Indicators and Triggers SUEZ Example Table is still under development Parameter Units Range of Results Action Trigger Total Phosphrous (P) mg/l Chlorophyll a ug/l Secchi Depth (Water Clarity) M Blue-Green Algal Cell Counts cells/ml 0-493,469 Geosmin ng/l < MIB ng/l < Greater than 0.05 mg/l; trigger to treat lake with nutrient inactivator NOT chelated copper product 20 to 30 ug/l; trigger to perform algae/cyanobacteria cell counts to determine the dominant algal group Less than 1 meter; trigger to perform algae/cyanobacteria cell counts, and possible lake treatment 5000 cells/ml; trigger to treat lake with chelated copper product, however, lower thresholds may apply depending on season/ species > 10 ng/l (Implement PAC) > 10 ng/l (Implement PAC) 46

13 Cyanotoxin Monitoring Will be needed to determine treatment needs and process adjustments. And will be required in UCMR4 ( ) ELISA (total Microcystins) EPA Health Advisories LC/MS/MS (Individual cyanotoxins and congeners) - Microcystin (LR, LA, LF, LY, RR, YR) - Nodularin - Anatoxin-a - Cylindrospermopsin AWWA has tools available to help you make monitoring and treatment decisions

14 Via the AWWA Website Through a collaborative effort with Hazen and Sawyer and Utah State University, AWWA is providing free tools to utilities through AWWA s Cyanotoxins Resource Community. Tools include: - A spreadsheet tool to assess removal of extracellular cyanotoxins by chlorine, ozone, chlorine dioxide, and potassium permanganate. - A Powdered Activated Carbon Calculator tool to assess proper dosages for toxin removal. 41

15 A Case Study in Monitoring and Management Addressing nuisance blue-green algae in Lambertville Reservoir, Symptom (July 2012), high densities of blue-green algae, clogging filters, creating taste and odor compounds, increasing treatment costs and causing concerns about Cyanotoxins Cause, elevated nutrient concentrations, particularly phosphorus, the warm still-water habitat and long-term changes in prevailing weather patterns (climate change). Summer started approximately 6 weeks earlier than usual.

16 Social Media Just a few drops DATE POSTED: Thursday, January 17, :05 AM EST To express my reaction to the knowledge that Anabaena is present in our water is in one word called scared. It takes only a few drops of this toxic water for it to be harmful to people and pets. Toxin Found In Brains Of Dead Alzheimer's Victims Substance Made By Algae Common In Lakes, Oceans By Margaret Munro CanWest News Service

17 Monitoring, Management and Treatment Plan (MMT Plan) Monitoring Collect site-specific data in the reservoir to assess and respond to conditions Management Implementation of both in-lake and watershed-based measures to improve overall water quality. Utilize alternate source (canal), if necessary. Treatment Develop more of a pro-active than reactive treatment strategy for the reservoir. Implement control measures at the WTP.

18 Monitoring 31 reservoir monitoring events were scheduled for February November 2013 Collected a variety of water quality data, including temperature, DO, ph, conductivity, water clarity, nutrients (nitrogen / phosphorus), suspended solids, chlorophyll a, plankton (phyto- / zoop-) - Also included the regular collection and analysis of samples for geosmin and MIB, and triggered monitoring of cyanotoxins, per WHO guidelines (beyond State regulations)

19 Monitoring Results in 2013 From March to mid-may TP concentrations were moderate ( mg/l) However, by late May and through mid-august TP concentrations were excessive (greater than or equal to 0.05 mg/l, the NJ State criteria) High densities of algae throughout the growing season with dominant groups being chrysophytes, diatoms and green algae in spring and diatoms through the summer (unlike 2012!). The exception was an early spring bloom of blue-green algae (Anabaena; 14 March 2013)

20 Management Strategies (In-Lake and Watershed) Conducted a bathymetric assessment of the reservoir Developed a hydrologic budget Developed a pollutant (TN, TP and TSS) budget Installed a de-stratification, aeration system in the reservoir Monitor alternate source of supply (canal)

21 Installation of De-stratification / Aeration System

22 Aeration Benefits Helped maintain measurable amounts of dissolved oxygen throughout the water column over the summer season Reduced the release of phosphorous from bottom sediment, which could have fueled algae growth

23 Depth (Meters) Lambertville Reservoir Dissolved Oxygen Profile at Station 4 2 August Dissolved Oxygen (ppm)

24 In-Lake Management Measures De-stratification/ aeration system (completed) Use of nutrient inactivation (not effective) Floating Wetland Islands (future) Biomanipulation (fish stocking, etc. TBD)

25 Watershed-Based Management Measures Streambank / shoreline stabilization Creation / expansion of riparian / wetland edge Possible stormwater management of residential / agricultural lands Preserve / protect forested lands within the watershed (horse farm)

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27 Treatment Strategy for the Reservoir Use water quality data to determine when to treat as oppose to sticking to scheduled treatments (e.g. twice a month starting in June) Make an effort to treat during the log phase of a bloom (I.e. high rates of growth) don t wait too long, and monitor frequently Use of liquid chelated copper-based algicides (CaptainR the first half of growing season and Earth TecR the second half)

28 Water Treatment Plant Upgrades Installation of Powdered Activated Carbon (PAC) system, as a back up for MIB/Geosmin and cyanotoxin control Upgrade of filters (added media) to accommodate PAC system load Capital improvements: an upgraded pump station to allow for the use of an alternate water source (canal)

29 Summary Chrysophytes, green algae and diatoms dominated the reservoir in 2013 Blue-green algae were not the dominant group, which is at least partially attributed to the destratification / aeration system Geosmin concentrations were consistently below the detection limit throughout 2013 No triggered monitoring for cyanotoxins required

30 Monitoring and Treatment Strategy Reduced the Magnitude of Blooms

31 Conclusions (2013) The de-stratification system helped improve water quality and minimize cyanobacteria growth; in turn, this contributed to keeping geosmin concentrations low in MIB concentrations increased periodically, but this only occurred when TP concentrations were 0.05 mg/l or greater. PAC system provided adequate treatment/ removal. More frequent monitoring of WQ parameters helped determine the most appropriate times to apply algaecides. Small-scale, spot treatments of copper-based algicides, at the initiation of high growth rates of filamentous mat algae helped keep algae and MIB concentrations in control in 2013.

32 Conclusions In 2013 No unmanageable algal blooms No unmanageable taste and odor events No need to test for cyanotoxins, per WHO guidelines Restored customer satisfaction!

33 2014 A Big Bloom in late August

34 2014 Geosmin Levels

35 2015 Cyanobacteria Levels

36 The Years in Review To summarize the weather over the last four years: dry and hot early summer (low reservoir levels) dry but somewhat cool summer somewhat wet spring / near normal summer 2012 dry and hot summer (also, Hurricane Sandy)

37 Lessons Learned Did we get too comfortable with the good water quality conditions we saw through early August (this worked in 2013) Should we have monitored more and treated in late July 2014, upon seeing an increase in algal cell counts? WQTC HAB/Cyanotoxin workshop indicated that others had the same experience in 2014 Need to learn reservoir management changes under the new plan and how year-to-year seasonal variations impact your approach We utilized another component of the MMT switching to an alternate source (canal) Low reservoir levels and no flow is a deadly combination reservoir treatment becomes restricted by your permit requirements. SUEZ Water needed to rely on other components of the MMT (I.e. alternate source of supply)

38 Future Actions Continue monitoring program with increased monitoring/ treatment during the early/ mid-summer period. Further development of treatment strategy table. Discontinue the application of Phos-Lock R, a clay-based product that inactivates phosphorus similar to alum but with no aluminum (not for internal load control; strips water column of P). Consider the installation of Floating Wetland Islands to remove some of the available nutrients in the water column (emphasis on phosphorus). Remain aware of developing technologies

39 Online Monitoring Using Multi-parameter Probes Looking into the use of multi-probe to simultaneously measure: phycocyanin (PC) fluorescence chlorophyll-a (Chl-a) fluorescence ph, temperature dissolved oxygen conductivity turbidity Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a. Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume. Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources. Zamyadi A1, McQuaid N, Prévost M, Dorner S. 2012

40 Addressing Multiple Objectives Systems must simultaneously manage and address a number of issues: Provide an adequate supply of potable water Remove / disinfect microbes Control formation of disinfection byproducts Prevent/ achieve removal of taste and odor causing compounds Maintain corrosion control Maintain reliable treatment under a wide range of conditions Managing cyanotoxins effectively requires identifying recognition & response strategies that do not create unintended consequences

41 Thanks! Contact Information: Keith Cartnick Sr. Director Water Quality and Compliance SUEZ Member AWWA Technical Advisory Group (TAW) on Cyanobacteria & Cyanotoxins Phone: