Embed Size (px)
Citation preview
LLuminescent uminescent DDissolved issolved OOxygen (xygen (LDOLDO) ) Measurements for Measurements for Wastewater ApplicationsWastewater Applications
Edward C. Craig, Ph.D.*Edward C. Craig, Ph.D.*
Cary B. Jackson, Ph.D.Cary B. Jackson, Ph.D.
Christopher P. FairChristopher P. Fair
Hach CompanyHach Company
Loveland, COLoveland, CO
Purpose of this Talk…Purpose of this Talk…
Discuss our effort to add Discuss our effort to add Luminescence (Luminescence (LDOLDO) to the List of ) to the List of EPA Approved Methods for EPA Approved Methods for Dissolved Oxygen MeasurementsDissolved Oxygen Measurements
Proposed EPA Method 360.3Proposed EPA Method 360.3
Specifically…Specifically…
Discuss our Discuss our In-House PreparationIn-House Preparation for a for a External Nationwide External Nationwide Validation StudyValidation Study run as Part of a run as Part of a Tier 3 EPA Approval Process for the Tier 3 EPA Approval Process for the Luminescence MethodLuminescence Method
Also share Also share somesome of the results of the results from the External Validation Studyfrom the External Validation Study
Current EPA Approved Current EPA Approved Methods for Measuring Methods for Measuring Dissolved Oxygen Conc.Dissolved Oxygen Conc.
Winkler Titration (1888)Winkler Titration (1888) EPA Method 360.2EPA Method 360.2
Membrane Electrodes (1959)Membrane Electrodes (1959) EPA Method 360.1EPA Method 360.1
Winkler TitrationWinkler Titration
L.W. Winkler, “The Determination L.W. Winkler, “The Determination of Dissolved Oxygen in Water”, of Dissolved Oxygen in Water”, Ber. Deut. Chem. GesBer. Deut. Chem. Ges., ., 2121, 2843 , 2843 (1888)(1888)
EPA “EPA “Reference MethodReference Method” for ” for Dissolved Oxygen MeasurementDissolved Oxygen Measurement
Winkler Titration – Winkler Titration – ReactionsReactions
264
2322
23
232
3
3222
22
22
6236)(2
)(22
1)(2
)(2
OSIOSI
III
OHIMnIHOHMn
OHMnOHOOHMn
OHMnOHMn
Winkler Method – Floc FormationWinkler Method – Floc Formation
Winkler Method - TitrationWinkler Method - Titration
Winkler TitrationWinkler Titration
ProsPros Direct DO MeasurementDirect DO Measurement Easy Clean-upEasy Clean-up
ConsCons Samples must be Analyzed in a LaboratorySamples must be Analyzed in a Laboratory Subject to Several Chemical InterferencesSubject to Several Chemical Interferences Very Technique SensitiveVery Technique Sensitive
Membrane ElectrodeMembrane Electrode
L.C. ClarkL.C. Clark ““Clark Cell”Clark Cell” Patent Nov. 19, Patent Nov. 19,
19591959
Membrane ElectrodeMembrane Electrode
ProsPros In-situ Measurements PossibleIn-situ Measurements Possible Easy to Make MeasurementsEasy to Make Measurements
ConsCons Frequent Maintenance RequiredFrequent Maintenance Required Must be Polarized Before UseMust be Polarized Before Use Must be Calibrated Before UseMust be Calibrated Before Use Consumes OxygenConsumes Oxygen Very Sensitive to Sample FlowVery Sensitive to Sample Flow
Luminescent Dissolve Oxygen Luminescent Dissolve Oxygen ((LDOLDO))
Completely New TechnologyCompletely New Technology
Measures the Quenching of a Measures the Quenching of a Luminescent Reaction caused by Luminescent Reaction caused by OxygenOxygen
Luminescent Dissolved Luminescent Dissolved Oxygen (Oxygen (LDOLDO) - Probe) - Probe
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen
((LDOLDO) ) Probe ComponentsProbe Components
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
LEDPhoto Diode
Probe
LED
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
LEDPhoto Diode
Probe
Sensor
LED
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
LEDPhoto Diode
Probe
Sensor
LED
Oxygen
LuminescentIndicator
Molecules Gas PermeablePolymer Matrix
Clear, GasImpermeable
Substrate
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
ProsPros No MaintenanceNo Maintenance Field Measurements PossibleField Measurements Possible No PolarizationNo Polarization Insensitive to Sample FlowInsensitive to Sample Flow RuggedRugged
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
Pros (cont.)Pros (cont.) AccurateAccurate PrecisePrecise Very Stable CalibrationsVery Stable Calibrations No Chemical InterferrentsNo Chemical Interferrents Lower Day-to-Day Cost than Winkler Lower Day-to-Day Cost than Winkler
TitrationTitration
Luminescent Dissolved Oxygen Luminescent Dissolved Oxygen ((LDOLDO))
ConsCons Higher Initial Cost than Winkler Higher Initial Cost than Winkler
TitrationTitration Not Currently EPA ApprovedNot Currently EPA Approved
External Validation External Validation Study…Study…
12 Wastewater Laboratories 12 Wastewater Laboratories NationwideNationwide
Accuracy & Precision (IPR)Accuracy & Precision (IPR) Method Detection Limit (MDL) Method Detection Limit (MDL)
Determn.Determn. 5 Day BOD5 Day BOD Side-by-side Comparisons with Side-by-side Comparisons with
Other DO MethodsOther DO Methods
In-House Preparation for In-House Preparation for External Validation External Validation Study…Study…
Preparation of Replicate DO StandardsPreparation of Replicate DO Standards Shelf-Life ExperimentShelf-Life Experiment Shipping ExperimentShipping Experiment Ruggedness TestingRuggedness Testing Use Model ComparisonsUse Model Comparisons Accuracy & Precision DeterminationsAccuracy & Precision Determinations MDL DeterminationMDL Determination BODBOD55 Demonstration Demonstration Side-by-side Comparison with Other Side-by-side Comparison with Other
MethodsMethods
Accuracy & Precision Accuracy & Precision DeterminationsDeterminations
Dissolved Oxygen Concentration Measured with LDO vs. Theoretical Disolved Oxygen Concentration
y = 1.0048x
R2 = 0.9993
0
2
4
6
8
10
12
0 2 4 6 8 10 12
Theoretical DO Conc. (mg/L)
Dis
solv
ed O
xyg
en C
on
c. (
mg
/L)
Mea
sure
d b
y L
DO
Comparison of LDO, Clark Electrode, and Winkler Titration DO Measurementsto Theoretical Hitchman Values
0
2
4
6
8
10
12
0 2 4 6 8 10 12
Theoretical DO Conc. (mg/L)
Mea
sure
d D
O C
on
c. (
mg
/L)
Clark Electrode
Winkler Titration
LDO
Theoretical
Percent Recovery at 1.69 mg/LPercent Recovery at 1.69 mg/L
Percent Recovery at 1.69 mg/L
100.9
104.3
101.5
94
96
98
100
102
104
106
LDO Clark Cell Winkler
Method Used to Measure DO Conc.
Per
cen
t R
eco
very
Percent Recovery in Air-saturated Water (6.91 mg/L)
101.2 100.8
97.2
94
96
98
100
102
104
106
LDO Clark Cell Winkler
Method Used to Measure DO Conc.
Per
cen
t R
eco
very
Percent Recovery in Air-saturated Percent Recovery in Air-saturated WaterWater
MDL DeterminationMDL Determination
LDO – In-House Method Detection LDO – In-House Method Detection LimitLimit
In-House MDL Determination for LDOAvg 0.070 (+/- 0.007) mg/L, MDL ~ 0.023 mg/L
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
1 2 3 4 5 6 7
LDO Instrument
Mea
sure
d D
O C
on
c. (
mg
/L)
Pooled MDL and ML Results Pooled MDL and ML Results (mg/L)(mg/L)
Data SourceData Source Pooled MDLPooled MDL MLML
In-house StudyIn-house Study 0.020.02 0.070.07
Inter-laboratory Inter-laboratory StudyStudy 0.060.06 0.180.18
PooledPooled 0.050.05 0.160.16
BODBOD55 Demonstration Demonstration
BODBOD55 Comparison Comparison
BOD's Measured using Different Methods for DO Measurements
0
50
100
150
200
250
Sam ple Description
Mea
sure
d B
OD
(m
g/L
)
LDO
Membrane
Winkler
Comparison of Glucose and Glutamic Acid Quality Control Checks(correct BOD value 198 mg/L)
190.5 191.3197.5
211.5
192.0 197.0
165.0
198.8192.5
0
50
100
150
200
250
Dilution 1 Dilution 2 Dilution 3
Mea
sure
d B
OD
(m
g/L
)
LDO
Membrane Electrode
Winkler Titration
Method Comparison – DO Measurements Influent Method Comparison – DO Measurements Influent and Effluent Samples from 12 Different and Effluent Samples from 12 Different Wastewater FacilitiesWastewater Facilities
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
LDO (mg/L)
Met
ho
d D
O (
mg
/L)
Winkler
Membrane
LDO Reference
Membrane
Winkler
What’s Next?What’s Next?
Report for External Validation Study has Report for External Validation Study has been submitted to EPAbeen submitted to EPA
Next the results are opened to the public Next the results are opened to the public for Review and Comments (~ 3 mo.)for Review and Comments (~ 3 mo.)
Expect Full EPA Approval in 12 to 18 Expect Full EPA Approval in 12 to 18 monthsmonths
Currently Partitioning EPA for Provisional Currently Partitioning EPA for Provisional Approval (6 to 12 mo.)Approval (6 to 12 mo.)
Soliciting/Helping WW Labs seeking Tier 1 Soliciting/Helping WW Labs seeking Tier 1 ApprovalsApprovals
Contacts…Contacts… Edward C. Craig, Ph.D.Edward C. Craig, Ph.D.
Research & Development ChemistResearch & Development Chemist [email protected]@hach.com
Cary B. Jackson, Ph.D.Cary B. Jackson, Ph.D. Regulatory ChemistRegulatory Chemist [email protected]@hach.com
Christopher FairChristopher Fair Wastewater Applications ChemistWastewater Applications Chemist [email protected]@hach.com
