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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