Representative Sampling EPA Region 9, Clean Water Act Compliance Office CWEA 35th Annual

Representative SamplingRepresentative SamplingEPA Region 9, Clean Water Act Compliance OfficeEPA Region 9, Clean Water Act Compliance Office

CWEA 35th AnnualCWEA 35th Annual

P3S Conference P3S Conference

February 27, 2008February 27, 2008

Long Beach, CaliforniaLong Beach, California

Greg V. ArthurGreg V. Arthur

US EPA, 75 Hawthorne Street, San Francisco, CA 94105US EPA, 75 Hawthorne Street, San Francisco, CA 94105

(415) 972-3504(415) 972-3504

Arthur.greg@epa.govArthur.greg@epa.gov

40 CFR 403.12(e)(1)40 CFR 403.12(e)(1)

Self-MonitoringSelf-MonitoringRequirementsRequirements

40 CFR 403.12(g)(1)40 CFR 403.12(g)(1)

Self-MonitoringSelf-MonitoringRequirementsRequirements

40 CFR 403.12(g)(1)40 CFR 403.12(g)(1)

Self-MonitoringSelf-MonitoringRequirementsRequirements

40 CFR 403.12(g)(3)40 CFR 403.12(g)(3)

Self-MonitoringSelf-MonitoringRequirementsRequirements

40 CFR 403.12(g)(3)40 CFR 403.12(g)(3)

Self-MonitoringSelf-MonitoringRequirementsRequirements

40 CFR 403.1240 CFR 403.12

Self-MonitoringSelf-MonitoringRequirementsRequirements

The Bottom LineThe Bottom LineThe Bottom LineThe Bottom Line

• Twice per year Twice per year reportsreports of self-monitoring.of self-monitoring.

• Each sample must be Each sample must be representative over the representative over the sampling day.sampling day.

• The sample record must The sample record must be representative over be representative over the six-month reporting the six-month reporting period.period.

40 CFR 403.1240 CFR 403.12

Self-MonitoringSelf-MonitoringRequirementsRequirements

So …So …Self-MonitoringSelf-MonitoringComplies with Fed RegsComplies with Fed Regs

So …So …Self-MonitoringSelf-MonitoringComplies with Fed RegsComplies with Fed Regs

If …If …All samples together are All samples together are representative of therepresentative of theflow, nature, and concen-flow, nature, and concen-tration of the dischargetration of the dischargeover the entire six-monthover the entire six-monthreporting period.reporting period.

The Test forThe Test forRepresentative SamplingRepresentative SamplingThe Test forThe Test forRepresentative SamplingRepresentative Sampling

Are there enough samples Are there enough samples taken at the right times from taken at the right times from the right locations to be the right locations to be representative of the representative of the discharge over the entire discharge over the entire six-month reporting period?six-month reporting period?

Federal MinimumFederal MinimumCan one 24-hr comp sampleCan one 24-hr comp samplebe representative over abe representative over asix-month reporting period?six-month reporting period?

Federal MinimumFederal MinimumCan one 24-hr comp sampleCan one 24-hr comp samplebe representative over abe representative over asix-month reporting period?six-month reporting period?

Yes, but only if …Yes, but only if …• Consistent flow and natureConsistent flow and nature• Random distributionRandom distribution• Variability only from BATVariability only from BAT• Little variability from opsLittle variability from ops

Are there enough samples taken at Are there enough samples taken at the right times and locations to be the right times and locations to be representative of the discharge over representative of the discharge over the six-month reporting period?the six-month reporting period?

Complication #1Complication #1

Independent eventsIndependent events• batch treatmentbatch treatment

• spent solutionsspent solutions

• intermittent operationsintermittent operations

continuous treatcontinuous treatfor metals rinsesfor metals rinses

lamellalamellaclarifierclarifier

batch treatbatch treatfor CNfor CNspentsspents

batch treatbatch treatfor metalsfor metals

spentsspents

~7 days~7 days

intermittentintermittentbatch treatbatch treatfor CNfor CNspentsspents

batch treatbatch treatfor metalsfor metals

spentsspents

lamellalamellaclarifierclarifier

continuous treatcontinuous treatfor metals rinsesfor metals rinses

spents spents

spentsspents

rinsesrinses

continuouscontinuous

intermittentintermittent

sample sample pointpoint How many samples are necessary to capture How many samples are necessary to capture

both independent events (continuous & 7day)?both independent events (continuous & 7day)?

How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

continuouscontinuousonlyonly

continuouscontinuousplus ~7day batchplus ~7day batch

How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs 1 - 10ooooo

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How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs 11 - 20ooooooooooooooo

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How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs 21 - 30oooooo

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How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs 31 - 40oo

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How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs 41 - 50o

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How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Mean = 7.0 StDev = 5.4

Probability of capturing bothindependent events in:1 sample – 15%2 samples – 20%3 samples – 25%6 samples – 43% (monthly)7 samples – 50%12 samples – 80%20 samples – 99%

How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Mean = 3.0 StDev = 2.5

Probability of capturing bothindependent events in:1 sample – 21%2 samples – 34%3 samples – 50%4 samples – 66%5 samples – 79%6 samples – 88% (monthly)9 samples – 99%

How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

An Independent Event is any An Independent Event is any significant source of variability in significant source of variability in the discharge quality or flowthe discharge quality or flowLikely significant sourcesLikely significant sourcesProcessProcess spent solutionsspent solutions

seasonalseasonalO&MO&Mblowdownsblowdowns

TreatmentTreatment batch treatmentbatch treatmentdewateringdewatering

DischargeDischarge combined sourcescombined sources

Are there enough samples taken at Are there enough samples taken at the right times and locations to be the right times and locations to be representative of the discharge over representative of the discharge over the six-month reporting period?the six-month reporting period?

Complication #2Complication #2

Non-random BiasNon-random Bias• weekend operationsweekend operations

• periodic contributionsperiodic contributions

• scheduled blowdownsscheduled blowdowns

How many samples are necessary to capture How many samples are necessary to capture both independent events (continuous & 7day)?both independent events (continuous & 7day)?

Runs Mon – SunMon ooooooooooooooo

Tue ooo

Wed oooooooooooooooooo

Thu ooooooooooo

Fri ooooooo

Sat oo

Sun oooooooooooooooo

1 Mon-Fri and 1 Sat-Sun

Complication #1Complication #1

Independent eventsIndependent events• test prior to dischargetest prior to discharge

• sampling to cover all eventssampling to cover all events

• determine if on schedulesdetermine if on schedules

• meteringmetering

• equalizationequalizationComplication #2Complication #2

Non-random BiasNon-random Bias• scheduled samplingscheduled sampling

• equalizationequalization

Representative SamplingRepresentative SamplingEPA Region 9, Clean Water Act Compliance OfficeEPA Region 9, Clean Water Act Compliance Office

CWEA 35th AnnualCWEA 35th Annual

P3S Conference P3S Conference

February 27, 2008February 27, 2008

Long Beach, CaliforniaLong Beach, California

Greg V. ArthurGreg V. Arthur

US EPA, 75 Hawthorne Street, San Francisco, CA 94105US EPA, 75 Hawthorne Street, San Francisco, CA 94105

(415) 972-3504(415) 972-3504

Arthur.greg@epa.govArthur.greg@epa.gov