September 2011, Vol. 23, No.9

Certification Quiz

Test your knowledge of biochemical oxygen demand

    True or False Questions:
  1. Nitrogenous demand is considered an interferent in the determination of 5-day biochemical oxygen demand (BOD).
  2. If nitrification is inhibited, results are reported as CBOD.
  3. Any final dissolved oxygen (DO) reading that is less than 1 mg/L may not be used in the BOD calculation.
  4. Any final DO reading that does not yield a total depletion of 2 mg/L is fine to use to calculate BOD.

  5. Multiple Choice Questions:
  6. What are the components of a GGA standard solution?

  7. A. 198 mg of glucose and 198 mg of glutamic acid per 1 L of water
    B. 150 mg of glucose and 150 mg of glutamic acid per 1 L of water
    C. 200 mg of glucose and 200 mg of glutamic acid per 1 L of water
    D. 99 mg of glucose and 99 mg of glutamic acid per 1 L of water

  8. What is the true value of the GGA standard?

  9. A. 198 mg/L
    B. 300 mg/L
    C. 150 mg/L
    D. 500 mg/L

  10. Which of the following is the proper range for seed correction factor (SCF)?

  11. A. 0.1 – 1.1 mg/L
    B. 1.0 – 2.0 mg/L
    C. 0.5 – 1.5 mg/L
    D. 0.6 – 1.0 mg/L

  12. All samples for BOD are incubated for 5 days at what temperature?

  13. A. 20°C ± 1°C
    B. 25°C ± 1°C
    C. 20°C ± 5°C
    D. 25°C ± 5°C

  14. Which of the following pH ranges should samples be within prior to analysis?

  15. A. 6.0 to 8.0
    B. 7.0 to 9.0
    C. 6.5 to 7.5
    D. 5.0 to 7.0

  16. Using the following data, calculate the seed correction factor.

    Initial DO concentration

    9.00 mg/L

    Final DO concentration

    5.25 mg/L

    Volume of seed used in control bottle

    20 mL

    Volume of seed used in samples and GGA

    4 mL

    Volume of bottle used

    300 mL

     

  17. A. 0.75
    B. 1.50
    C. 0.05
    D. 0.60

  18. Using the following data, calculate the GGA standard result.

     

    Initial DO concentration

    9.00 mg/L

    Final DO concentration

    4.50 mg/L

    Seed correction factor

    0.6

    Volume of seed added to GGA

    4 mL

    Volume of GGA added to 300-mL bottle

    6 mL

     

  19. A. 198 mg/L
    B. 195 mg/L
    C. 293 mg/L
    D. 150 mg/L

  20.  Using the following data, calculate the 5-day BOD of a sample.

     

    Initial DO concentration

    9.00 mg/L

    Final DO concentration

    4.00 mg/L

    Seed correction factor

    0.6

    Volume of seed added to sample

    4 mL

    Volume of sample added to 300-mL bottle

    100 mL

     

  21. A. 1.47 mg/L
    B. 25.3 mg/L
    C. 13.2 mg/L
    D. 15.2 mg/L

Questions developed by Joe Boyd, technical specialist at Environmental Express (Charleston, S.C.), and reviewed by the Operations forum Editorial Advisory Board and the Association of Boards of Certification (Ankeny, Iowa) Wastewater Treatment Validation and Examination Committee.

Answer Key:
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