Calculation of Range of Dilutions for Acceptable BOD Results
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Transcript of Calculation of Range of Dilutions for Acceptable BOD Results
Calculation of Range of Dilutions forAcceptable BOD Results
Prepared ByMichigan Department of Environmental Quality
Operator Training and Certification Unit
BOD PROCEDUREBOD PROCEDURE
DILUTE SAMPLE
Minimum Residual, 1.0 mg/LMinimum Depletion, 2.0 mg/LAt Least Two Dilutions
Calculation of Range of Acceptable BOD Results
BOD Sample =Depletion
X 300 mLSample Volume
Minimum BOD =Minimum Depletion
X 300 mLSample Volume
Minimum BOD =2.0
X 300Sample Volume
Minimum BOD = 600Sample Volume
Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion
Example
What is the Lowest Acceptable BOD results if 20 mL of sample is used?
Minimum BOD = 600Sample Volume
Minimum BOD = 60020
Minimum Acceptable BOD = 30 mg/L
Minimum BOD That May Be Reported =600
Sample Volume
Example 2
What is the Lowest Acceptable BOD results if 150 mL of sample is used?
Minimum BOD = 600Sample Volume
Minimum BOD = 600150
Minimum Acceptable BOD = 4 mg/L
Calculation of Range of Acceptable BOD Results
Maximum BOD =D.O. In – 1.0
X 300 mLSample Volume
Maximum BOD =7.0
X 300Sample Volume
Maximum BOD = 2100Sample Volume
Highest (Maximum) Acceptable Results
ASSUMING Initial D.O. of 8.0 mg/L
Lowest Acceptable Residual
– Highest Acceptable Depletion
Depletion = 8.0 - 1.0 = 7.0
Example
What is the highest Acceptable BOD results if 20 mL of sample is used?
Maximum BOD = 2100Sample Volume
Maximum BOD = 210020
Maximum Acceptable BOD = 105 mg/L
Maximum BOD That May Be Reported =2100
Sample Volume
Example 2
What is the highest Acceptable BOD results if 150 mL of sample is used?
Maximum BOD = 2100Sample Volume
Maximum BOD = 2100150
Maximum Acceptable BOD = 14 mg/L
Maximum BOD That May Be Reported =2100
Sample Volume
Calculation of Range of Acceptable BOD Results
Minimum BOD = 600Sample Volume
Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion
Summary
Highest (Maximum) Acceptable Results
Lowest Acceptable Residual
– Highest Acceptable Depletion
Maximum BOD = 2100Sample Volume
(Assuming D.O. In =8.0 mg/L
Calculation of Range of Acceptable BOD Results
Minimum BOD = 600Sample Volume
Wait A Minute
Maximum BOD = 2100Sample Volume
600 X 3.5 = 2100600 X 3.5 = 2100
So (assuming D.O. In is 8.0)
Minimum BOD x 3.5 = Maximum BODMinimum BOD x 3.5 = Maximum BOD
Calculation of Range of Acceptable BOD Results
Minimum BOD = 600Sample Volume
Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion
Summary (again)
Highest (Maximum) Acceptable Results
Lowest Acceptable Residual
– Highest Acceptable Depletion
(Assuming D.O. In =8.0 mg/L
Maximum BOD = 3.5 X Minimum BOD
Example
What is the Lowest Acceptable BOD results if 30 mL of sample is used?
Minimum BOD = 60030 = 20 mg/L
What is the Highest Acceptable BOD results if 30 mL of sample is used?
20 mg/L X 3.5 = 70 mg/L
Total Range when using a 30 mL sample:
20 to 70 mg/L
Total Range when using a 100 mL sample = 6 to 21 mg/L
Total Range when using a 150 mL sample = 4 to 14 mg/L
Total Range when using 100 mL and 150 mL (two Bottles)
Total Range when using a 50 mL sample = 12 to 42 mg/L
= 4 to 21 mg/L
Total Range when using 50 mL and 150 mL (two Bottles)
= 4 to 42 mg/L
OVERLAP From 6 to 14 mg/L
OVERLAP From 12 to 14 mg/L
Total Range when using a 25 mL sample = 24 to 84 mg/L
Total Range when using a 125 mL sample = 4.8 to 16.8 mg/L
Total Range when using 25 mL and 125 mL (two Bottles)
NO: Does Not Include 16.8 to 24 mg/L
= 4.8 to 84 mg/L
Range To Wide (No Overlap)
?
Calculate Range of Acceptable BOD Results
Use Two Volumes that Expand the RangeBut
Give a “Comfortable” Overlap
Calculate Range of Acceptable BOD Results
Use Two Volumes that Expand the RangeBut
Give a “Comfortable” Overlap
Calculate Range of Acceptable BOD Results
Use Two Volumes that Expand the RangeBut
Give a “Comfortable” Overlap
Calculation of Range of Dilutions forAcceptable BOD Results
Prepared ByMichigan Department of Environmental Quality
Operator Training and Certification Unit