1. 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

2. 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

3. 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

4. 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

5. 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
Humans
Exposure routes in humans
Dermal
Oral (water or food)
Inhalation
Dialysis
Included on US EPAs CCL3
Produce toxins during genetic strain, growth phase, competition, environmental conditions

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

7. Cyanotoxin Occurrence
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

8. 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
drinking waters
Lake Erie Source:
Potassium Permanganate, PAC, Lime Softening, Filtration, Chlorine
Raw water filtration, Ozone, adsorption clarifier, chlorine disinfection

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

10. 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)
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

11. 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)
Precipitation
5 to 10% increase, mostly in fall and winter (Frumhoff et al, 2007)
Storms
Increasing trends in extreme precipitation (Spierre and Wake, 2010)

12. What will OH’s climate look like?
Lower Emissions Scenario
Higher Emissions Scenario
Adapted from Frumhoff et al, 2007

13. 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)

14. 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.
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

15. UV/H2O2 AOP H2O2 absorbs UV energy and degrades to 2 OH radicals
Only 1 OH radical per UV photon
Due to “water caging”
H2O2 OH
Org OH
UV Absorbance of H2O2
Org
H2O2 OH OH
H2O
H2O
H2O2

16. Fundamentals – UV/H2O2 AOP16
Fundamentals – UV/H2O2 AOP
Pollutant or Constituent
OH radical rate constant (M-1 s-1)
Reference
MTBE
Atrazine
NDMA
MIB
Geosmin
Bisphenol-A
17-b-Estradiol
17-a-Ethinyl Estradiol
4-Nonylphenol
Para-Chlorobenzoic Acid
Nitrobenzene
Methanol
NOM (TOC)
HCO3-
CO3-2
H2O2
1.9x109
3x109
3.3x109
8.2x109
1.4x1010
1.02x1010
1.41x1010
1.08x1010
5.65x109
5x109
3.9x109
9.7x109
2.5x104 (L mg-1 s-1)
8.5x106
3.9x108
2.7x107
Acero et al., 2001
Acero et al., 2000
Wink and Desrosiers, 1991
Glaze et al., 1990
Rosenfeldt and Linden, 2004
AWARF, 2006
Elovitz and von Gunten, 1999
Buston et al., 1988
Buxton et al., 1988
Larson and Zepp, 1988
Hoigne et al., 1985; Buxton et al, 1988
Hoigne et al., 1985; Buxton et al., 1988
AOP  High powered oxidation of contaminants via OH radical intermediate
OH radical is very reactive with “targets”
OH radical is also reactive with “scavengers”

17. 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”
Disinfection
Photolysis
AOP

18. UV AOP for Taste and Odor
UV Photolysis
UV Advanced Oxidation
Rosenfeldt and Linden, 2005
UV Advanced Oxidation for Geosmin Oxidation at Cornwall, ON
TrojanUV, 2010

19. UV AOP for Algal Toxins UV and UV AOP for m-LR destruction
UV AOP for MIB and algal toxins at Cornwall, ON
Alvarez et al, 2010
Approximate Geosmin removal
UV and UV AOP for m-RR destruction
Faster due to photolysis of Microcystin and Anatoxin
TrojanUV, 2010
Qiao et al, 2005

20. 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%.
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

21. Why UV AOP makes some sense
“Instant-on” technology
Effective Disinfection / Innovative Technology
Comparable replacement for other T&O treatment processes
Pantin, 2009

22. 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
H2O2 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
Cornwall relies on ad-hoc “odor panel” – municipal employees and research scientists – in the service area to determine when to “ramp-up” to AOP conditions.
Pantin, 2009

23. 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”)
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
1 log Geosmin oxidation only 0.5 log MIB oxidation
Civardi and Lucca, 2010

24. 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
BPA

25. 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
Anatoxin-a
250 mg/kg
Anatoxin-a(S)
20 mg/kg
MIB
No toxicity

26. 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 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

27. 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 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

28. Questions?
Erik Rosenfeldt, P.E., PhD Hazen & Sawyer Fairfax