Understanding the Ecology and Monitoring Tools for Cyanobacteria Blooms Impacting a Water Treatment Plant Jill Crumb, B.Sc., TreeFrog Environmental Tim Walton, B.Sc., Pam Law, P.Eng., Regional Municipality of Waterloo Leigh McDermott, M.E.Sc., P.Eng., Stantec Consulting

CWWA 15th Canadian National Annual Conference

Agenda •  Background •  Cyanotoxin Regulatory Guidelines •  Aquatic Ecology •  Monitoring Program •  Results •  Summary

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Project Background

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Hidden Valley Reservoir

•  The Regional Municipality of Waterloo (RMOW) is proactively monitoring the Hidden Valley Reservoir for cyanobacteria activity

•  The reservoir is fed from the Grand River and supplies the Mannheim WTP (72 MLD capacity)

•  RMOW: •  Population: > 550,000 •  Area: 1,382 km2 •  Two Tier System

Hidden Valley Reservoir

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•  Large reservoir structure with 140 million litres (ML) storage in 4 cells –  Water flows in an under-over path prior to being

conveyed to the Mannheim WTP •  Timeline:

–  2010: cyanobacteria discovered and impacted cells isolated

–  Spring 2011: mitigation measures were implemented in Cell 3

–  2011 and 2012: routine monitoring carried out to understand growth factors and treatment needs

Cyanobacteria – why the fuss? •  Cyanobacteria, also known as blue-green algae,

are photosynthetic bacteria •  Capable of producing cyanotoxins: very potent

toxins with varying health effects •  Historical records as far back as

1000 years (poisoning of soldiers in S. China)

•  Linked to animal illness in Canada for over 50 years

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Cyanotoxin Regulatory Guidelines

Standard Cyanotoxin Standard

Ontario Drinking Water Quality Standard MC-LR: 1.5 µg/L Canadian Drinking Water Quality MC-LR: 1.5 µg/L Australian Drinking Water Guidelines MC-LR: 1.3 µg/L

Currently considering: anatoxin-a, saxitoxin, and cylindrospermopsin

World Health Organization (provisional guideline)

MC-LR: 1.0 µg/L

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•  Over 80 structural variants of the Microcystin toxin group •  Most common cyanotoxin is Microcystin-LR (MC-LR) •  Other cyanotoxins: anatoxin, saxitoxin, nodularin and

cylindrospermopsin

Aquatic Ecology of Cyanobacteria

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Planktonic cyanobacteria •  can regulate their location in

the water column •  eg. Microcystis, Anabaena,

Oscillatoria

Benthic cyanobacteria •  attach to surfaces •  eg. Phormidium, Lyngbia,

Oscillatoria

water surface

waterbody walls/bottom

Surface cyanobacteria •  can be planktonic or

detached benthic mats

Cyanobacteria Growth Factors •  Temperature •  Light Penetration (Turbidity) •  Light Intensity and Quality •  Nutrients

– Total Concentration – Ratio of N:P (10-16:1)

•  Alkalinity and pH

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Source: EPA

Monitoring Program Objectives •  Growth factors specific to the Hidden

Valley Reservoir (HVR) •  Determination of cyanobacteria taxa •  Determination of average and worst-case

toxin load that may pass to the Mannheim WTP

•  Methodology for determination of cyanobacteria counts

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Tools – Probes Cyanobacteria •  YSI 600 OMS V2

sonde and handheld data logger with phycocyanin probe

•  Measures “Real Flourescence Units”

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Water Quality •  YSI ProPlus sonde and handheld data logger

with probes for temperature, pH and dissolved oxygen

Tools – Strip Tests and Analytical •  Abraxis Test Kit for

Source Drinking Water –  Includes lysing step –  Detection to 5 ppb

•  Laboratory Analysis –  nitrate, nitrite,

ammonia-N –  total-P and ortho-P –  turbidity and DOC

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Monitoring Methodology

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•  Monitoring window: mid-June to late-Oct

•  Composite samples for Cells 2 to 4, and grab sampling of Low-Lift and High-Lift

•  “In Situ” sampling using probes and strip tests

•  Analytical testing

Results from 2011 Cyanobacteria present: •  Anabaena •  Anacystis •  Gomphosphaeria •  Oscillatoria

Cyanotoxin (MC-LR) levels at the High-Lift have always been well below MAC of 1.5 µg/L

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1

10

100

1000

10000

100000

Cell C

ount

sin C

ells/m

L (L

og10

)

Sample Location

Anabaena

Anacystis

Oscillatoria

Gomphosphaeria

Results – Growth Factors

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•  Three primary factors identified: – Nitrite Concentration

•  Literature suggests metabolic pathway for nitrites

– Retention Time •  Bloom corresponded to increase in retention time

– Mixing •  Mixers installed in

Cell 3

Results – Growth Factors

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0.00

0.02

0.04

0.06

0.08

0.10

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-Jun

30-Ju

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Nitri

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Date

LL C2 C3 C4 HL

Bloom

Results – Growth Factors

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0

1

2

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5

6

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-Jun

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Rete

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)

Phyc

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(PC-

RFU)

Date

LL C2 C3 C4 HL Retention Time

Results – Growth Factors

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0

1000

2000

3000

4000

5000

6000

Cell C

ount

(Calc

ulat

ed C

ells/m

L)

Reservoir Location

Cyanobacteria Cell Count Through Reservoir - Sept 28, 2011

Tools – Best Practices Fluorescence Probe •  Good quantitative results

for cyanobacteria counts •  Possible to use for true

“in situ” or grab samples •  Correlation needed for

specific source water •  Good correlation to

laboratory verified MC-LR concentrations

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y = 208.94x1.3379

y = 2080.7x0.999

0

50000

100000

150000

200000

250000

0.1 1 10 100

Cells

/mL

PC-RFU Reading

Probe Correlation

Enumerated Cyanobacteria Cells/mL

Probe Reading Cells/mL

Power (Enumerated Cyanobacteria Cells/mL)

Power (Probe Reading Cells/mL)

Tools – Lessons Learned Strip Tests •  Relatively quick confirming test

–  Test requires approximately 90 minutes

•  Rapid strip test resolution was poor –  Did not detect low level MC-LR

concentrations –  Sometimes difficult to read

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Summary •  Cyanobacteria Ecology

–  Understanding of taxonomy is important for guiding monitoring needs

–  Monitoring frequency and water quality data tracking is important for trend identification

–  Monitoring should be increased during a bloom event •  Monitoring Tools

–  Laboratory confirmation of toxins –  Strip tests rapid but resolution should be examined –  Fluorescence probes reliable but cost is higher and

require correlation –  Spatial monitoring can be beneficial but labour and

health and safety needs are important considerations

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Acknowledgements •  Peter Clarke, RMOW •  Kathy Taylor, RMOW •  All our cyanobacteria pals…. •  And not to mention green algae too….

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Questions?

Jill Crumb, TreeFrog Environmental jill@treefrogenv.ca

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