Calculation of Range of Dilutions for Acceptable BOD
Calculation of Range of Dilutions for Acceptable BOD Results Prepared By Michigan Department of Environmental Quality Operator Training and Certification Unit
BOD PROCEDURE DILUTE SAMPLE Minimum Residual, 1. 0 mg/L Minimum Depletion, 2. 0 mg/L At Least Two Dilutions
Calculation of Range of Acceptable BOD Results BOD Sample = Depletion Sample Volume X 300 m. L Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion Minimum BOD = Minimum Depletion Sample Volume 2. 0 Sample Volume Minimum BOD = 600 X 300 m. L X 300 Sample Volume
600 Minimum BOD That May Be Reported = Sample Volume Example What is the Lowest Acceptable BOD results if 20 m. L of sample is used? Minimum BOD = 600 Sample Volume 600 20 Minimum Acceptable BOD = 30 mg/L
Example 2 What is the Lowest Acceptable BOD results if 150 m. L of sample is used? Minimum BOD = 600 Sample Volume 600 150 Minimum Acceptable BOD = 4 mg/L
Calculation of Range of Acceptable BOD Results Highest (Maximum) Acceptable Results – Highest Acceptable Depletion Lowest Acceptable Residual Maximum BOD = D. O. In – 1. 0 Sample Volume X 300 m. L ASSUMING Initial D. O. of 8. 0 mg/L Depletion = 8. 0 - 1. 0 = 7. 0 Maximum BOD = 7. 0 Sample Volume Maximum BOD = 2100 X 300 Sample Volume
2100 Maximum BOD That May Be Reported = Sample Volume Example What is the highest Acceptable BOD results if 20 m. L of sample is used? Maximum BOD = 2100 Sample Volume 2100 20 Acceptable BOD = 105 mg/L
2100 Maximum BOD That May Be Reported = Sample Volume Example 2 What is the highest Acceptable BOD results if 150 m. L of sample is used? Maximum BOD = 2100 Sample Volume 2100 150 Maximum Acceptable BOD = 14 mg/L
Calculation of Range of Acceptable BOD Results Summary Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion Minimum BOD = 600 Sample Volume Highest (Maximum) Acceptable Results – Highest Acceptable Depletion Lowest Acceptable Residual (Assuming D. O. In =8. 0 mg/L Maximum BOD = 2100 Sample Volume
Calculation of Range of Acceptable BOD Results Wait A Minute Minimum BOD = Maximum BOD = 600 Sample Volume 2100 Sample Volume 600 X 3. 5 = 2100 So (assuming D. O. In is 8. 0) Minimum BOD x 3. 5 = Maximum BOD
Calculation of Range of Acceptable BOD Results Summary (again) Lowest (Minimum) Acceptable Results – Lowest Acceptable Depletion Minimum BOD = 600 Sample Volume Highest (Maximum) Acceptable Results – Highest Acceptable Depletion Lowest Acceptable Residual (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 m. L of sample is used? Minimum BOD = 600 30 = 20 mg/L What is the Highest Acceptable BOD results if 30 m. L of sample is used? 20 mg/L X 3. 5 = 70 mg/L Total Range when using a 30 m. L sample: 20 to 70 mg/L
Total Range when using a 100 m. L sample = 6 to 21 mg/L Total Range when using a 150 m. L sample = 4 to 14 mg/L Total Range when using 100 m. L and 150 m. L (two Bottles) = 4 to 21 mg/L OVERLAP From 6 to 14 mg/L Total Range when using a 50 m. L sample = 12 to 42 mg/L Total Range when using 50 m. L and 150 m. L (two Bottles) = 4 to 42 mg/L OVERLAP From 12 to 14 mg/L
Total Range when using a 25 m. L sample = 24 to 84 mg/L Total Range when using a 125 m. L sample = 4. 8 to 16. 8 mg/L Total Range when using 25 m. L and 125 m. L (two Bottles) = 4. 8 to 84 mg/L ? NO: Does Not Include 16. 8 to 24 mg/L Range To Wide (No Overlap)
Calculate Range of Acceptable BOD Results Use Two Volumes that Expand the Range But Give a “Comfortable” Overlap
Calculate Range of Acceptable BOD Results Use Two Volumes that Expand the Range But Give a “Comfortable” Overlap
Calculate Range of Acceptable BOD Results Use Two Volumes that Expand the Range But Give a “Comfortable” Overlap
Calculation of Range of Dilutions for Acceptable BOD Results Prepared By Michigan Department of Environmental Quality Operator Training and Certification Unit
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