Treatment of Algae using the Kria Water Treatment ...

Treatment of Algae using the Kria Water Treatment System Victor F. Medina, Ph.D., P.E. Research Environmental Engineer

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Background  The KRIA Water Treatment System is a reactor that works by producing superoxide, a negatively charged oxygen radical, and charging it into the water body of interest using a recirculation cell.  Previous ERDC studies showed that the KRIA was effective at treatment of diesel and also enhanced removal of PCBs.  A video of the KRIA in action can be found at: https://www.youtube.com/watch?v=b3UJnz88Lxs&list=U U1o9qwSHbkghwo-HPbimbIQ

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Contributors    

Chris Griggs, Research Chemist Catherine Thomas, Research Biologist Agnes Morrow, Chemist Roy Wade, Research Engineer

 Direct questions and inquiries to Dr. Victor Medina, [email protected], 601 634 4283

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The KRIA Reactor  Field Deployment of the KRIA  The KRIA in the laboratory  The recirculation pump  The superoxide generation system

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Superoxide  Negatively charged oxygen (O2-)  Less reactive than hydroyxl or persulfate radicals  Can work both oxidatively & reductively  Literature indicates reactions with a wide range of contaminants, including carbon tetrachloride, nitroaromatic compounds, and hydrocarbons.  Shepard et al. (1998) showed degradation of microcystin toxin

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Other reactive mechanisms of the KRIA  Increases oxygen content promoting enhanced biodegradation  Microbubbles, which have been shown to degrade contaminants, disinfection, and promote contaminant desorption  Cavitation at the injection nozzle. May promote radical formation.

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Background studies  Determine how KRIA affects water quality  Run KRIA in tap water in 55 gallon drum reactors (50 gallons)  With superoxide valve on and off  Measure water quality parameters  Measure superoxide (SO) production

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Background studies

55 gallon drum reactors

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KRIA superoxide reservoir with valve (orange) off

Multipurpose water quality meter


Impact of KRIA operation on Water Quality (55 gallon study) Mixing Time (minutes) WQ Parameter SO Valve Open temp C Closed Open cond mS/cm Closed Open DO mg/L Closed Open DO % Closed Open pH Closed Open ORP Closed

0 20.33 20.28 0.170 0.136 8.63 10.34 94.1 113.0 5.95 4.68 -35.3 -22.5

10 20.85 20.36 0.265 0.138 30.21 9.13 331.6 101.0 6.44 5.28 -23.0 -31.0

30 21.62 20.85 0.305 0.139 30.62 9.09 347.3 102.0 6.65 5.71 -29.3 -32.7

60 23.65 21.58 0.355 0.146 30.41 8.91 356.2 100.8 6.93 6.04 -46.3 -37.6

80 23.18 22.04 0.355 0.149 30.16 8.76 352.9 100.7 6.99 5.87 -51.7 -36.8

24 hr 135 recovery 23.06 21.03 22.68 0.353 0.337 0.150 29.37 28.55 8.56 343.4 321.9 100.0 6.92 6.65 6.28 -59.6 -41.3 -41.7

 Substantial increases in DO and DO saturation due to addition of oxygen (as superoxide), and elevated levels maintained after 24 hr recovery  Increase of conductivity due to addition of negative oxygen anion, which is largely maintained after 24 hr recovery.  ORP increased in open and closed (cavitation effect). BUILDING STRONG®


Superoxide measurement (using Superoxide Dimutase Assay)

Plate reader

96-well microplate used in superoxide measurement

 Enzyme Linked Immunosorbent Assay (ELISA) based test  Semi-quantitative measurement (relative comparison between different treatments)  Kria treated, with and without superoxide BUILDING STRONG®


Superoxide 1600 1400

Superoxide Units

1200 1000 800

Superox Control

600 400 200 0 0

1

2

3 4 Kria Operational Time (hrs)

5

 Enhanced superoxide activity in the superoxide treated reactor.  Some activity found in control, possibly due to cavitation reactions

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Algae Treatment Approach  Obtained cyanobacteria from lake water from sources in California and from Lake Eire, OH.  Mixed 5 gallons with 45 gallons of preconditioned water (tap water treated by ion exchange to make it suitable for fish growth).  Three treatments for California sample ► ► ►

No treatment, control KRIA with superoxide valve off (KRIA w/SO) KRIA with superoxide valve on (KRIA w/o SO)

 KRIA with superoxide only for Lake Erie Sample (Lake Erie)

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Experimental

Bucket of collected algae used to spike 55 gallon drum reactors

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55 gallon drum reactors with artificial lighting


Algae Treatment – Visual Comparison

Kria treated with Superoxide versus Control (40 min. treatment)

Kria treated without Superoxide versus Control (5 min. treatment)

 Dramatic decrease in algae coloration and visible green particulate matter with KRIA treatment, with and without superoxide  Without superoxide actually produced a more clear end result after less treatment time, but the initial sample was noticeably less concentrated. BUILDING STRONG®


Counts of Microcystin aeruginosa Study

Treatment Control Study 2 - California Lake Kria with Superoxide with High Cell Density Kria without Superoxide Kria with Superoxide Study 3 - Lake Erie

Initial Biovolume Initial Count (NU/mL) Final Count (NU/mL) %Count Change (um3/mL) 3.70E+07 3.08E+07 17% 1.72E+09 3.40E+07 6.32E+06 81% 1.10E+09 1.72E+07 1.17E+07 32% 5.34E+08 7.56E+05 5.81E+05 23% 3.83E+07

Final Biovolume (um3/mL) 1.18E+09 2.16E+08 3.37E+08 2.80E+07

%Biomass Change 32% 80% 37% 27%

• Microcystin aeruginosa was counted by Phycotech, Inc. of St. Joseph, MI. • Microcystin aeruginosa accounted for 80 to 98% of the algal/cyanobacterial population by counts in control and post treated samples. • It was not possible to determine if cells were active (living) or not in the counting process. • The best treatment was achieved by the KRIA with superoxide, which had 80% reductions of counts and biomass

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Volatile Matter (Organic Matter) Normalized Concentration (C/Co)

1.2

1.0

0.8

0.6

Control Kria

0.4

0.2

0.0 0

  

10

20 30 Treatment time (min)

40

50

VM was used as a measure of biomass. KRIA treatment (w/ SO) resulted in a more than 80% reduction in VM (65% reduction in control) in 40 minutes of treatment KRIA without SO had a 75% reduction in 5 minutes. Lake Erie study had a 65% reduction.

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Spectrophotometer Scan

 

Spectrophotometer scan undertaken from electromagnetic spectrum from 600 to 700nm. Drastic decrease in in adsorbance due to destruction of photosynthetic pigments.

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Chlorophyll Chlorophyll Concentration (mg/L)

12.0

10.0

8.0

6.0

Control Kria

4.0

2.0

0.0 0

 

10


40

50

Chlorophyll concentrations dropped 80% in the Kria treated (w/ SO) reactor while actually increased in the control. Decreases were also found in Kria w/o SO (90% in 5 min) and in the Lake Erie treated samples (75% in 5 min).

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Turbidity 1600.0 1400.0

Turbidity (NTU)

1200.0 1000.0 800.0

Control Kria

600.0 400.0 200.0 0.0 0

   

10


40

50

Turbidity is the measure of light scattering in water and is a function of particles in the water Algal cells can act as light scattering particles The Kria Treated (w/ SO) sample had >90% reduction of turbidity after 40 minute treatment. There was no reduction of turbidity in the control. Kria treated w/ SO and Lake Erie treatments had 84% reductions in turbidity after 5 minutes

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Microcystin Toxin Concentrations Treatmemt Study Treatment time (min) Study 1 - California Lake Control 40 Kria with Superoxide 40 with Medium Cell Kria without Superoxide 40 Density Control 5 5 Study 2 - California Lake Kria with Superoxide 5 with High Cell Density Kria without Superoxide Study 3 - Lake Erie Kria with Superoxide 5

Time Zero Microcystin Concentration (ug/L) 146 146 138 555 555 215 5.5

Post Treatment Microcystin Concentration (ug/L) 138 34 44 215 47 28 1.8

% Reduction 5% 77% 68% 61% 92% 87% 67%

• Microcystin measured by GreenWater Laboratories (Palatka FL) using ELISA method with a detection limit of 0.15 ug/L after ultrasonication (to lyse cells) & filtration • KRIA treatments with and without superoxide charging resulted in substantial reduction of microcystin toxins compared to controls.

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Issue - clogging

 With the Lake Erie treatment, we found that some of the algae was in the form a stringy mat.  This clogged the metallic pretreatment column.  We could only achieve treatment with further dilution of the sample BUILDING STRONG®


Conclusions  The KRIA is effective at treating harmful algae, as supported by visual observations, counts of Microcystin aeruginosa, volatile matter, chlorophyll, and turbidity. ► Different

measurements had different sensitivities. Counts had the lowest, but could not differentiate between living and inactive

 The treatment was also effective at substantially reducing microcystin toxin concentrations.

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Conclusions (continued)  Effective treatment was generally found with and without superoxide. ► Cavitation

alone is an effective mechanism ► The literature indicates that cavitation can produce radicals, including hydroxl radicals ► Superoxide did appear to enhance reduction of M. aeruginosa counts ► Some differences in treatment maybe due to changes in the initial reactor conditions

 5 minute exposure in the drum was sufficient to create effective change. Even lower exposure times maybe effective. BUILDING STRONG®


Questions  Clogging issues ► Our

studies used diluted samples –clogging could be a frequent issue ► Could the KRIA be modified to address this?

 How would the reactor work in an open water deployment? ► Radius

of influence? ► Residual effectiveness? ► Frequency of treatment?

 Energy & costs? ► Is

treatment ultimately cost-effective?

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Concept for Field Study

 Construct some in place reactors to isolate the treatment in the lake.  Apply KRIA treatment in one reactor, monitor changes in a control.  Follow up with open water study to study treatment radius.

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Concept for Deployment  We do not endorse this or other products, but are simply applying our engineering knowledge to explore applications.  KRIA treatments could be applied to bays, coves, and other areas where HABs begin, either after monitoring suggests an imminent bloom or even just periodically. By controlling blooms in these sensitive areas, it may limit spread of HABs throughout a larger lake or reservior.  KRIA treatments can be applied to beaches or areas where human contract with HABs could occur  KRIA reactors could be deployed around water intakes, to provide preliminary treatment prior to intake into a potable water treatment system.

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Application around water intake

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