COMPLETING DISCHARGE MONITORING REPORTS

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NPDES ENFORCEMENT SECTION
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Completing Discharge Monitoring Reports
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Subjects To Be Covered

• Definitions and formulas necessary to complete
  DMR
• A closer look at a preprinted DMRS
• An example DMR problem (step by step through the
  process of completing the DMR)
• Common errors

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DEFINITIONS AND FORMULAS

• DAILY DISCHARGE
• MONTHLY AVERAGE
• 30-DAY AVERAGE
• 7-DAY AVERAGE
• LOADING (AVERAGE AND MAXIMUM)
• GEOMETRIC MEAN (FOR FECAL COLIFORM)

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MOST PERMITTEES DONT TAKE MORE THAN ONE SAMPLE
PER DAY. IF YOU ONLY COLLECT ONE GRAB SAMPLE PER
DAY OR LESS, THE DAILY DISCHARGE DEFINITION
MEANS THE ONE SAMPLE REPRESENTS THE DISCHARGE FOR
THAT DAY.
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THIS IS THE DEFINITION OF MONTHLY AVERAGE
CONCENTRATION. UNLIKE A NORMAL AVERAGE,
MONTHLY AVERAGE CONCENTRATION IS A FLOW WEIGHTED
AVERAGE. FORMULA BELOW
C1F1 C2F2 C3F3 CnFn Flow weighted
average F1F2F3Fn Where C
sample concentration in mg/l F flow on the
day of sample
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Very few NPDES Permits still retain 30-day
average limitations. Most have been replaced
with monthly average.
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THE 30-DAY AVERAGE IS NOT FLOW WEIGHTED LIKE A
MONTHLY AVERAGE. FORMULA BELOW
C1 C2 C3 Cn average
n Where C sample concentration in
mg/l n number of samples
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7-day averages are not flow weighted The Saturday
rule determines which month the 7-day average is
reported See further explanation of Saturday rule
on next two slides
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THE 7-DAY AVERAGE IS NOT FLOW WEIGHTED LIKE A
MONTHLY AVERAGE. FORMULA IS SAME AS 30-DAY
AVERAGE
C1 C2 C3 Cn average
n Where C sample concentration in
mg/l n number of samples
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7-DAY AVERAGE
Samples collected the last week of May will be
used to calculate the monthly average in May, but
the 7-Day Average of these samples will be
reported in June because the Saturday of this
week falls in June.
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LOADING CALCULATIONS
FORMULA FOR LOADING (SAMPLE CONC. in mg/l) (FLOW
IN MGD)(8.34) LBS
FORMULA FOR MONTHLY AVERAGE LOADING L1 L2
L3 .Ln AVERAGE LOADING n
Where L the calculated loading for the sample
day n the number of sample days
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CALCULATING A GEOMETRIC MEAN
A calculator capable of performing Logarithmic
functions is required.
Use the following formula
Log(FCB1) Log(FCB2) Log(FCB3) Log (FCBn)
Logavg n
Antilog(Logavg) Geometric Mean Where
Log(FCB) logarithm of fecal coliform colony
count n number of samples
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NOW LETS GO OVER COMPLETING A DISCHARGE
MONITORING REPORT.
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MATERIALS NEEDED

• Laboratory reports/analytical data.
• Preprinted discharge monitoring report (DMR).
• Calendar.
• Calculator capable of performing Logarithmic
  functions.
• Flow data.
• Scratch paper.

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FIRST, LETS EXAMINE A TYPICAL LABORATORY
REPORTING SHEET
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LETS EXAMINE A PREPRINTED DISCHARGE MONITORING
REPORT
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EXAMPLE PROBLEM

• THE HIGHEST DAILY RECORDED (DAILY MAXIMUM) FLOW
  IS 120,000 GALLONS PER DAY.
• THE MONTHLY (DAILY) AVERAGE FLOW IS CALCULATED TO
  BE 75,000 GALLONS PER DAY.
• THE FLOW IS MONITORED DAILY.

Flow is reported in million gallons per day, so
the maximum flow is 0.120 mgd and the average
flow is 0.075 mgd.
The next slide shows how the flow is reported on
the DMR.
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EXAMPLE PROBLEM
Calculate Monthly Average Concentration and 7-Day
Average Concentration
Given BOD 10 mg/l, flow 0.050 mgd, May 8,
2000 BOD 20 mg/l, flow 0.075 mgd, May 18,
2000 BOD 25 mg/l, flow 0.060 mgd, May 29, 2000
Monthly Average Concentration
(10 mg/l)(0.050 mgd) (20 mg/l)(0.075 mgd) (25
mg/l)(0.060 mgd)
(0.050 mgd) (0.075 mgd) (0.060 mgd) (0.50)
(1.5) (1.5) 18.9 mg/l monthly average
concentration. 0.185
7-Day Average Concentration
20 mg/l is the highest 7-Day Average. The 7-day
average sample collected on May 29, 2000, will be
reported in June because of Saturday rule.
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EXAMPLE PROBLEM
Calculate Monthly Average Loading
Given BOD 10 mg/l, flow 0.050 mgd, May 8,
2000 BOD 20 mg/l, flow 0.075 mgd, May 18,
2000 BOD 25 mg/l, flow 0.060 mgd, May 29, 2000
L1 (10 mg/l)(0.050 mgd)(8.34) 4.17 lbs/ day
on May 8, 2000 L2 (20 mg/l)(0.075 mgd)(8.34)
12.51 lbs/day on May 18, 2000 L3 (25
mg/l)(0.060 mgd)(8.34) 12.51 lbs/day on May 29,
2000 4.17 lbs/day 12.51 lbs/day 12.51 lbs/day
29.19 9.73 lbs/day avg. 3 3
The next slide shows how these calculations are
reported on the DMR.
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EXAMPLE PROBLEM
Lets assume the TSS and ammonia samples are the
same as the BOD samples (concentration and flow).
Since the calculations are the same, the answers
are the same. See the DMR on next page with the
TSS and ammonia completed.
Note the arrow on the next page points to the
No.Ex block for ammonia. Of the three samples
only one is counted in the No.Ex column. The
10 mg/l sample is below the 7-day average limit
and the 25 mg/l sample is counted as a 7-day
average in June because of the Saturday rule.
Therefore, the only sample to exceed the maximum
limit was the 20 mg/l sample on May 18, 2000.
The next slide shows how these calculations are
reported on the DMR.
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EXAMPLE PROBLEM
Calculate the 30-Day Geometric Mean and 7-Day
Geometric Mean for Fecal Coliform (Fecal Strep
would be calculated in the same manner)
Given fecal coliform 20 col/100 ml, May 8,
2000 fecal coliform 200 col/100 ml, May 18,
2000 fecal coliform 2000 col/100 ml , May 29,
2000
30-Day Geometric Mean log 20 1.3 log 200
2.3 log 2000 3.3 6.9/3 samples 2.3
antilog 200 col/100 ml
The 7-day geometric mean reported on the DMR will
be 200 col/100 ml because the sample collected on
May 29, 2001 is a 7-day average reported in June.
The next slide shows how the fecal coliform
calculations are reported on the DMR.
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EXAMPLE PROBLEM
Determine the instantaneous minimum dissolved
oxygen and the maximum and minimum pH
Given DO 4.5 mg/l, pH 7.6 SU, May 8, 2000 DO
3.7 mg/l, pH 7.2 SU, May 18, 2000 DO 4.6 mg/l,
pH 8.3 SU , May 29, 2000
The instantaneous minimum dissolved oxygen during
the month would be reported as 3.7 mg/l because
it was the lowest value recorded.
The minimum pH measurement would be reported as
7.2 SU and the maximum pH measurement as 8.3 mg/l.
The next slide shows how pH and DO are reported
on the DMR.
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Signature, Date, Telephone Number, and Executive
Officer Blocks Must Be Completed After Reading
the Certification Statement at the Bottom of the
DMR.
I CERTIFY UNDER PENALTY OF LAW THAT I HAVE
PERSONALLY EXAMINED AND AM FAMILIAR WITH THE
INFORMATION SUBMITTED HEREIN AND BASED ON MY
INQUIRY OF THOSE INDIVIDUALS IMMEDIATELY
RESPONSIBLE FOR OBTAINING THE INFORMATION, I
BELIEVE THE SUBMITTED INFORMATION IS TRUE,
ACCURATE, AND COMPLETE. I AM AWARE THAT THERE
ARE SIGNIFICANT PENALTIES FOR SUBMITTING FALSE
INFORMATION, INCLUDING THE POSSIBILITY OF FINE
AND IMPRISONMENT. SEE 18 U.S.C 1001 AND 33
U.S.C. 1319. (Penalties under these statutes may
includes fines up to 10,000 and or maximum
imprisonment of between 6 months and 5
years.)
The next slide shows how these sections are
completed on the DMR.
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Where Do I Send The Completed DMR
Send the original and first carbon copy of the
DMR to
ADEQ NPDES Enforcement Section P.O. Box
8913 Little Rock, AR 72219-8913

• Unless specifically requested, DO NOT SUBMIT
• Laboratory Sheets
• Flow Sheets
• Chain of Custody
• More than the original and one copy of the DMR.

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Common Errors in the Completion of DMRs

• Improperly completing the No.Ex. column. This
  column is to report the number of times you
  exceed a maximum limit (or 7-day average or
  minimum limit).
• Improperly completing the frequency of analysis
  column. This column is to report your actual
  sampling frequency (in numbers) and not just
  repeat the permit required frequency.
• Submitting all three carbon copies of the DMR.
• Submitting only the DMR carbon copies and not the
  original DMR. Original must be submitted because
  it contains the original signature.

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Common Errors

• Not completing all blocks on the DMR.
  Specifically, the date, telephone, and principal
  executive officer blocks along the bottom of the
  DMR and average and maximum sample measurements
  in the body of the DMR.
• Failing to sign the DMR.
• DMR signed by an unauthorized individual.
• Monitoring results are not legible
• Reporting an average value that is higher than a
  maximum value. (On rare occasions, a monthly
  average might be higher than a 7-day average.)
• Reporting results in the wrong units.
• Failure to put the name and address of contract
  laboratory on the DMR

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Commonly Made Mistakes in DMR Calculations

• Calculating monthly average loading using monthly
  average flow and monthly average concentration.
• Calculating maximum loading using maximum flow
  and highest concentration during the monitoring
  period.
• Calculating fecal coliform as an arithmetic mean.
  (Fecal coliform is calculated as a geometric
  mean.)
• Calculating monthly average concentration without
  flow weighting.
• Calculating 7-day average as a flow weighted
  average.
• Using sample data from outside the monitoring
  period.

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For more information please download the NPDES
Reporting Manual on the ADEQ Web Page.
http//www.adeq.state.ar.us/water/npdes_enf.htmHa
ndbook
Or e-mail or call your enforcement administrator
(EA)
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CREDITS
Graphics Courtesy of www.grandstandgraphics.com