UV Advanced Oxidation for

Treatment of Taste and Odor

and Algal Toxins

UV Advanced Oxidation for

Treatment of Taste and Odor

and Algal Toxins

Ohio AWWA Annual Conference

Research Workshop

September 20, 2011

Erik Rosenfeldt, PE, PhD

Ohio AWWA Annual Conference

Research Workshop

September 20, 2011

Erik Rosenfeldt, PE, PhD

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Presentation Agenda

• Algae issues

� Taste and Odor

� Toxic Substances

• Climate change impacts on algae events• Climate change impacts on algae events

• UV Advanced Oxidation

� Fundamentals

� Treatment of taste and odor, toxins

� Comparisons with other technologies

• Summary and Conclusions

Algae Issues

• Seasonal algae blooms present many problems for water utilities

� Depleted oxygen

� Turbidity

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� Taste and Odor

• Cyanobacteria

� “Blue-green” algae

� Not quite algae, not quite bacteria• Photosynthetic but lack well-defined nucleus

� Responsible for Taste and Odor compounds

� Create and may release toxic compounds

Algal Taste and Odor Compounds

• Methylisoborneol (MIB) and geosmin

� Musty/earthy odor detectable at low (5-10 ng/L levels)

� Non-toxic

� Released by cyanobacteria

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� Released by cyanobacteria

� Not regulated, but public perception rules

Cyanotoxins

• Some blue-green can produce one or more toxins� Do not produce toxins at all times

• Toxins can affect� Fish and other aquatic life

� Livestock

� Pets

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� Pets

� Humans

• Exposure routes in humans� Dermal

� Oral (water or food)

� Inhalation

� Dialysis

• Included on US EPAs CCL3

Cyanotoxins

Species Dermatoxin

(Irritant)

Hepatoxin (Liver) Neurotoxin

(Nervous)

Taste/Odor

Compound

Aphanacapsa spp. microcystins

Microcystis spp. microcystins, nodularin anatoxins

Snowella spp. microcystins

Synechococcus spp. microcystins MIB, Geosmin

Woronichinia spp. microcystins

Lyngbya spp. Lyngbyatoxins saxitoxins MIB

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Lyngbya spp. Lyngbyatoxins saxitoxins MIB

Oscillatoria spp. Aplysiatoxins microcystinsanatoxins, saxitoxins

MIB, Geosmin

Planktothrix agardhii Aplysiatoxins microcystins saxitoxins MIB, Geosmin

Pseudoanabaena spp. MIB, Geosmin

Anabaena spp.microcystins,

cylindrospermopsinanatoxins, saxitoxins

MIB, Geosmin

Anabaenopsis elenkii microcystins

Aphanizomenon spp.microcystins,

cylindrospermopsinanatoxins, saxitoxins

Geosmin

Cylindrospermopsis

raciborskiicylindrospermopsin saxitoxins

Nordularia spp. microcystins, nodularin

Tedesco et al, 2011

Cyanotoxin Occurrence

Indiana data

• Yearly occurrence

• Occurs during algal

blooms

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blooms

� Late summer, early fall

• Toxins typically released

during lysis

� Algae mitigation processes

can make problem worse

Tedesco et al, 2011

Cyanotoxins in Ohio

• Lake Erie and Grand Lake St. Marys Algal Blooms

• Last year: Ohio EPA testing revealed 0.23 and 0.16 ppb Microcystin in two treated

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Microcystin in two treated drinking waters

� Lake Erie Source:• Potassium Permanganate, PAC, Lime Softening,

Filtration, Chlorine

� Lake Erie Source:• Raw water filtration, Ozone, adsorption clarifier,

chlorine disinfection

Cyanotoxins and Taste and Odor

• USGS 2010 study (ES&T

44, 7361 – 7368)

• Sampled 23 Midwest lakes

� Multiple toxin classes co-

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� Multiple toxin classes co-

occurred in 48%

� Toxins and T&O co-occurred

in 91%

• No health risks during T&O

outbreaks?

Climate Impacts on Algae

• Temperature� Warmer temperatures encourage blooms (Pearl and

Huisman, 2008)

� Warmer temperatures increase the odor intensity of VOCs at very low concentrations, increasing consumer detection (Whelton et al., 2004)

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(Whelton et al., 2004)

• Precipitation� Long antecedent dry periods increase nutrient content of

runoff

� Low rainfall can cause stagnant conditions in the watershed

• Wind/storms� Heavy storms and strong wind can mix reservoirs,

reintroducing nutrients into the water column from bottom sediments

Northeast Climate Projections

• Temperature

� 3° to 7°C temperature increase by 2100 (Frumhoff et al, 2007)

� More frequent days over 35°C (Karl et al, 2009)

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(Karl et al, 2009)

• Precipitation

� 5 to 10% increase, mostly in fall and winter (Frumhoff et al, 2007)

• Storms

� Increasing trends in extreme precipitation (Spierre and Wake, 2010)

What will OH’s climate look like?

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2010 - 20392010 - 2039

Lower Emissions Scenario Higher Emissions Scenario

2010 - 2039

2040 - 2069

2070 - 2090

2010 - 2039

2040 - 2069

2070 - 2090

Adapted from Frumhoff et al, 2007

What can be done?

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• Algae blooms are getting more prevalent and

potentially more dangerous

• Fortunately, algae typically only occur in the

summer monthssummer months

• Several treatment processes are effective

� Activated Carbon

• GAC

• PAC

� Ozone

� UV Advanced Oxidation (UV AOP)

Advanced Oxidation Processes

■ An effective process for disinfection and chemical oxidation, capable of providing barriers for protecting public health and improving public perception

– Pharmaceuticals, Personal Care Products, EDCs

– Crypto, Viruses, E. coli, etc.

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– Crypto, Viruses, E. coli, etc.

■ AOPs work by creating hydroxyl radicals (•OH)

– •OH then blast away at organic chemicals

■ Usually an expensive chemical process

■ Complex chemistry

■ UV Based AOPs

■ UV/H2O2, UV/O3, UV/HOCl, etc.

■ Ozone Based AOPs

■ Ozone/H2O2, Ozone/NOM, Ozone/pH

• H2O2 absorbs UV energy and degrades to 2 OH radicals

• Only 1 OH radical per UV photon

• Due to “water caging”

UV/H2O2 AOP

H2O2

•OH

•OHOrg

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H2O2•OH •OH

H2O2

H2OH2O

Org

0

50

100

150

200

250

200 220 240 260 280 300

Wavelength (nm)

εε εε (M-1 cm

-1)

UV Absorbance of H2O2

Pollutant or

Constituent

OH radical rate

constant (M-1 s-

1)

Reference

MTBEAtrazineNDMAMIBGeosminBisphenol-A

β

1.9x109

3x109

3.3x109

8.2x109

1.4x1010

1.02x1010

Acero et al., 2001Acero et al., 2000

Wink and Desrosiers, 1991Glaze et al., 1990Glaze et al., 1990

Rosenfeldt and Linden, 2004

Fundamentals – UV/H2O2

AOP

• AOP � High powered oxidation of contaminants via OH radical intermediate� OH radical is very

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17-β-Estradiol17-α-Ethinyl Estradiol4-NonylphenolPara-ChlorobenzoicAcidNitrobenzeneMethanolNOM (TOC)HCO3

-

CO3-2

H2O2

1.41x1010

1.08x1010

5.65x109

5x109

3.9x109

9.7x109

2.5x104 (L mg-1 s-

1)8.5x106

3.9x108

2.7x107

Rosenfeldt and Linden, 2004Rosenfeldt and Linden, 2004

AWARF, 2006Elovitz and von Gunten, 1999

Buston et al., 1988Buxton et al., 1988

Larson and Zepp, 1988Hoigne et al., 1985; Buxton et al,

1988Hoigne et al., 1985; Buxton et al.,

1988Buxton et al., 1988

� OH radical is very reactive with “targets”

� OH radical is also reactive with “scavengers”

Differences between UV disinfection and AOP

• Some fundamental differences in� Levels of Applied UV Energy

� Fundamental Mechanisms

� UV Dose (ie what does it mean?)

• Different “Targets”

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• Different “Targets”

Disinfection Photolysis AOP

UV AOP for Taste and Odor

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UV Photolysis UV Advanced Oxidation

Rosenfeldt and Linden, 2005

UV Advanced Oxidation

for Geosmin Oxidation

at Cornwall, ON

TrojanUV, 2010

UV AOP for Algal Toxins

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UV AOP for MIB and algal toxins at

Cornwall, ON

UV and UV AOP for m-LR destruction

TrojanUV, 2010

UV and UV AOP for m-RR destruction

Alvarez et al, 2010Approximate Geosminremoval

Qiao et al, 2005

Taste and Odor as a surrogate for toxin oxidation?

• Characteristics of a good surrogate

� Co-occurrence (Graham et al, 2010)

• Microcystin co-occurred with geosmin in 87% of blooms, with MIB in 39%.

• Anatoxin-a co-occurred with geosmin in 100% of blooms, with MIB in 43%.

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in 43%.

� Similar trends of occurrence (Graham et al, 2010)

• Although toxins and T&O frequently co-occurred, concentrations were not strongly correlated (r < 0.4, p > 0.1)

• Not surprising because they are not produced by the same biochemical pathways

� Surrogate is conservative

• Microcystin LR and Anatoxin degraded faster than MIB, but not geosmin

Why UV AOP makes some sense

• “Instant-on” technology

• Effective Disinfection / Innovative Technology

• Comparable replacement for other T&O treatment

processes

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processes

Pantin, 2009

Why UV AOP makes some sense

Cornwall, ON• Trojan UV SwiftTM ECT Reactors (MP technology)

� UV system serves in disinfection mode” most of the year (4 of 8 lamps running)

� Can “ramp-up” to AOP conditions seasonally (8 lamps running, add H2O2)• 5 operational levels � UV dose ~ 400 – 60 mJ/cm2

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• 5 operational levels � UV dose ~ 400 – 60 mJ/cm– H2O2 varies 1, 2, 4, 8, 15 mg/L

Pantin, 2009

UV AOP replaces GAC filter caps for T&O control ($100,000/yr for GAC replacement).

UV provides excellent disinfection barrier

Why UV AOP makes some sense

Neshaminy Water Treatment Plant

� Civardi and Lucca, 2010 (OAWWA and Tricon) compared

costs and carbon footprint for 20 year design life

• 15 MGD Plant, Desired 1 log removal of “Geosmin and MIB”

• Assume 90 days per year of use (each is “instant-on”)

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• Assume 90 days per year of use (each is “instant-on”)

UV-H2O2 AOP PAC

Capital $2.5 mil $2.2 mil

O&M $200,000 $310,000

Equivalent Uniform Annual Cost (4%)

$384,000 $475,000

Civardi and Lucca, 2010

Why UV AOP makes some sense

• Byproducts?

� In most cases, this is a major impact on AOP feasibility

• Eg: Estrogenic activity of BPA goes away slower than BPA

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CH3CH3

OH OH

BPA

Byproducts

• In the case of UV AOP treatment of taste and odor and toxins, the story is simpler…� Taste and odor and toxic action are very dependent on molecular

structure

� Small changes in structure (ie oxidation, phototransformation, etc.) will likely diminish toxicity significantly

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will likely diminish toxicity significantly

Anatoxin-a250 µg/kg

Anatoxin-a(S)20 µg/kg

MIBNo toxicity

Wrap Up

• Algal toxins and algae related taste and odor outbreaks are both caused by seasonal, cyanobacteria outbreaks

• Recent research has indicated that presence of taste and odor (geosmin particularly), correlates

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taste and odor (geosmin particularly), correlates well with presence of algal toxins

• UV Advanced Oxidation effectively degrades both T&O and algal toxins

� In general, MIB < Geosmin ~ Anatoxin << Microcystin

� Cost and carbon footprint similar to Activated Carbon

� “Instant-on” Technology

Parting thought…

“Drinking water purveyors frequently tell customers

during taste-and-odor outbreaks that there are no

health risks. In our study, however, taste-and-odor

causing compounds were always accompanied by

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causing compounds were always accompanied by

cyanotoxins, highlighting the need for water

purveyors to increase cyanotoxin surveillance during

taste-and-odor outbreaks so that treatment can be

modified accordingly, and to verify that cyanotoxins

are not present at or above thresholds of potential

health risk.”Graham et al, 2010

Questions?

Erik Rosenfeldt, P.E., PhD

Hazen & Sawyer Fairfax

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703-537-7920

571-505-6601

erosenfeldt@hazenandsawyer.com