Presentation - Hazen and Sawyer

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

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Presentation Agenda
• Algae issues
Taste and Odor
Toxic Substances
• Climate change impacts on algae events
• UV Advanced Oxidation
Fundamentals
Treatment of taste and odor, toxins
Comparisons with other technologies
• Summary and Conclusions

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Algae Issues
• Seasonal algae blooms present many problems
for water utilities
Depleted oxygen
Turbidity
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

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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
Not regulated, but public perception rules

Cyanotoxins
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• 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
Humans
• Exposure routes in humans
Dermal
Oral (water or food)
Inhalation
Dialysis
• Included on US EPAs CCL3

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Cyanotoxins
Species
Aphanacapsa spp.
Dermatoxin
(Irritant)
Hepatoxin (Liver)
microcystins
Neurotoxin
(Nervous)
Microcystis spp. microcystins, nodularin anatoxins
Snowella spp.
microcystins
Taste/Odor
Compound
Synechococcus spp. microcystins MIB, Geosmin
Woronichinia spp.
microcystins
Lyngbya spp. Lyngbyatoxins saxitoxins MIB
Oscillatoria spp. Aplysiatoxins microcystins
anatoxins,
saxitoxins
MIB, Geosmin
Planktothrix agardhii Aplysiatoxins microcystins saxitoxins MIB, Geosmin
Pseudoanabaena spp.
Anabaena spp.
Anabaenopsis elenkii
Aphanizomenon spp.
Cylindrospermopsis
raciborskii
Nordularia spp.
microcystins,
cylindrospermopsin
microcystins
microcystins,
cylindrospermopsin
cylindrospermopsin
microcystins, nodularin
anatoxins,
saxitoxins
anatoxins,
saxitoxins
saxitoxins
MIB, Geosmin
MIB, Geosmin
Geosmin
Tedesco et al, 2011

Cyanotoxin Occurrence
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Indiana data
• Yearly occurrence
• Occurs during algal
blooms
Late summer, early fall
• Toxins typically released
during lysis
Algae mitigation processes
can make problem worse
Tedesco et al, 2011

Cyanotoxins in Ohio
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• 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
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
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• USGS 2010 study (ES&T
44, 7361 – 7368)
• Sampled 23 Midwest lakes
Multiple toxin classes cooccurred
in 48%
Toxins and T&O co-occurred
in 91%
• No health risks during T&O
outbreaks?

Climate Impacts on Algae
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• 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)
• 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
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• Temperature
3° to 7°C temperature increase by
2100 (Frumhoff et al, 2007)
More frequent days over 35°C
(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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Lower Emissions Scenario
Higher Emissions Scenario
2010 - 2039
2040 - 2069
2070 - 2090
2010 - 2039
2040 - 2069
2070 - 2090
Adapted from Frumhoff et al, 2007

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What can be done?
• Algae blooms are getting more prevalent and
potentially more dangerous
• Fortunately, algae typically only occur in the
summer months
• Several treatment processes are effective
Activated Carbon
• GAC
• PAC
Ozone
UV Advanced Oxidation (UV AOP)

Advanced Oxidation Processes
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■
■
■
■
■
■
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.
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/H 2 O 2 , UV/O 3 , UV/HOCl, etc.
Ozone Based AOPs
■
Ozone/H 2 O 2 , Ozone/NOM, Ozone/pH

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UV/H 2 O 2 AOP
• H 2 O 2 absorbs UV energy and
degrades to 2 OH radicals
• Only 1 OH radical per UV
photon
• Due to “water caging”
Org
•OH
H 2 O 2
•OH
UV Absorbance of H 2 O 2
ε (M -1 cm -1 )
250
200
150
100
50
0
200 220 240 260 280 300
Wavelength (nm)
Org
H 2 O
H 2 O 2 •OH •OH
H 2 O 2
H 2 O

Fundamentals – UV/H 2 O 2
AOP
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• AOP High powered
oxidation of
contaminants via OH
radical intermediate
OH radical is very
reactive with “targets”
OH radical is also
reactive with
“scavengers”
Pollutant or
Constituent
OH radical rate
constant (M -1 s -
1
)
Reference
MTBE
Atrazine
NDMA
MIB
Geosmin
Bisphenol-A
1.9x10 9
3x10 9
3.3x10 9
8.2x10 9
1.4x10 10
1.02x10 10 Acero et al., 2001
Acero et al., 2000
Wink and Desrosiers, 1991
Glaze et al., 1990
Glaze et al., 1990
Rosenfeldt and Linden, 2004
17-β-Estradiolβ
1.41x10 10 Rosenfeldt and Linden, 2004
H 2 O 2 2.7x10 7 1988
17-α-Ethinyl Estradiol 1.08x10 10 Rosenfeldt and Linden, 2004
4-Nonylphenol
5.65x10 9
AWARF, 2006
Para-Chlorobenzoic
5x10 9
Elovitz and von Gunten, 1999
Acid
3.9x10 9
Buston et al., 1988
Nitrobenzene
9.7x10 9
Buxton et al., 1988
Methanol
2.5x10 4 (L mg -1 s - Larson and Zepp, 1988
NOM (TOC)
1
)
Hoigne et al., 1985; Buxton et al,
HCO
-
3 8.5x10 6
1988
CO
-2
3 3.9x10 8 Hoigne et al., 1985; Buxton et al.,
Buxton et al., 1988

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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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
UV and UV AOP for m-LR destruction
UV AOP for MIB and algal toxins at
Cornwall, ON
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Approximate
Geosmin
removal
Alvarez et al, 2010
UV and UV AOP for m-RR destruction
TrojanUV, 2010
Qiao et al, 2005

Taste and Odor as a surrogate for toxin
oxidation?
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• 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%.
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
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• “Instant-on” technology
• Effective Disinfection / Innovative Technology
• Comparable replacement for other T&O treatment
processes
Pantin, 2009

Why UV AOP makes some sense
Cornwall, ON
• Trojan UV Swift TM 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 H 2 O 2 )
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• 5 operational levels UV dose ~ 400 – 60 mJ/cm
2
– H 2 O 2 varies 1, 2, 4, 8, 15 mg/L
UV AOP replaces GAC filter
caps for T&O control
($100,000/yr for GAC
replacement).
UV provides excellent
disinfection barrier
Pantin, 2009

Why UV AOP makes some sense
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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”)
UV-H 2 O 2 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

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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
H 3 C
CH 3
HO
OH
BPA

Byproducts
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• 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
Anatoxin-a
250 µg/kg
Anatoxin-a(S)
20 µg/kg
MIB
No toxicity

Wrap Up
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• 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
well with presence of algal toxins
• UV Advanced Oxidation effectively degrades both
T&O and algal toxins
In general, MIB < Geosmin ~ Anatoxin

Parting thought…
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“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
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

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Questions?
Erik Rosenfeldt, P.E., PhD
Hazen & Sawyer Fairfax
703-537-7920
571-505-6601
erosenfeldt@hazenandsawyer.com