Presentation is loading. Please wait.

Presentation is loading. Please wait.

UV Advanced Oxidation for Treatment of Taste and Odor and Algal Toxins Ohio AWWA Annual Conference Research Workshop September 20, 2011 Erik Rosenfeldt,

Similar presentations


Presentation on theme: "UV Advanced Oxidation for Treatment of Taste and Odor and Algal Toxins Ohio AWWA Annual Conference Research Workshop September 20, 2011 Erik Rosenfeldt,"— Presentation transcript:

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 Ohio AWWA Annual Conference Research Workshop September 20, 2011 Erik Rosenfeldt, PE, PhD

2 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 3

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 4

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 5

6 Cyanotoxins SpeciesDermatoxin (Irritant) Hepatoxin (Liver)Neurotoxin (Nervous) Taste/Odor Compound Aphanacapsa spp.microcystins Microcystis spp.microcystins, nodularinanatoxins Snowella spp.microcystins Synechococcus spp.microcystinsMIB, Geosmin Woronichinia spp.microcystins Lyngbya spp.LyngbyatoxinssaxitoxinsMIB Oscillatoria spp.Aplysiatoxinsmicrocystins anatoxins, saxitoxins MIB, Geosmin Planktothrix agardhiiAplysiatoxinsmicrocystinssaxitoxinsMIB, Geosmin Pseudoanabaena spp.MIB, Geosmin Anabaena spp. microcystins, cylindrospermopsin anatoxins, saxitoxins MIB, Geosmin Anabaenopsis elenkiimicrocystins Aphanizomenon spp. microcystins, cylindrospermopsin anatoxins, saxitoxins Geosmin Cylindrospermopsis raciborskii cylindrospermopsinsaxitoxins Nordularia spp.microcystins, nodularin 6 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 7 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  Lake Erie Source: Raw water filtration, Ozone, adsorption clarifier, chlorine disinfection 8

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? 9

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 10

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) 11

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

13 What can be done? 13 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/H 2 O 2, UV/O 3, UV/HOCl, etc. ■ Ozone Based AOPs ■ Ozone/H 2 O 2, Ozone/NOM, Ozone/pH 14

15 H 2 O 2 absorbs UV energy and degrades to 2 OH radicals Only 1 OH radical per UV photon Due to “water caging” UV/H 2 O 2 AOP H2O2H2O2 OH H2O2H2O2 H2OH2OH2OH2O H2O2H2O2 Org UV Absorbance of H 2 O 2 15

16 Pollutant or Constituent OH radical rate constant (M -1 s - 1 ) Reference MTBE Atrazine NDMA MIB Geosmin Bisphenol-A 17-  -Estradiol 17-  -Ethinyl Estradiol 4-Nonylphenol Para-Chlorobenzoic Acid Nitrobenzene Methanol NOM (TOC) HCO 3 - CO 3 -2 H 2 O 2 1.9x10 9 3x x x x x x x x10 9 5x x x x10 4 (L mg -1 s - 1 ) 8.5x x x10 7 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 Buxton et al., 1988 Fundamentals – UV/H 2 O 2 AOP AOP  High powered oxidation of contaminants via OH radical intermediate  OH radical is very reactive with “targets”  OH radical is also reactive with “scavengers” 16

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” DisinfectionPhotolysisAOP 17

18 UV AOP for Taste and Odor 18 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 19 UV AOP for MIB and algal toxins at Cornwall, ON TrojanUV, 2010 UV and UV AOP for m-RR destruction UV and UV AOP for m-LR destruction Alvarez et al, 2010 Approximate Geosmin removal 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 0.1) 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 20

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

22 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 ) 5 operational levels  UV dose ~ 400 – 60 mJ/cm 2 – H 2 O 2 varies 1, 2, 4, 8, 15 mg/L 22 Pantin, 2009 UV AOP replaces GAC filter caps for T&O control ($100,000/yr for GAC replacement). UV provides excellent disinfection barrier

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”) 23 UV-H 2 O 2 AOPPAC 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

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 24 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 25 Anatoxin-a 250  g/kg Anatoxin-a(S) 20  g/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 26

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.” 27 Graham et al, 2010

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


Download ppt "UV Advanced Oxidation for Treatment of Taste and Odor and Algal Toxins Ohio AWWA Annual Conference Research Workshop September 20, 2011 Erik Rosenfeldt,"

Similar presentations


Ads by Google