1. The temperature of the incubator used for a BOD test should be maintained at _.
a. 20 degrees F
b. 35 degrees F
c. 2 degrees C
d. 35 degrees C

2. What is the basic formula for determining BOD?
a. Oxygen depletion of the blank minus oxygen depletion of the sample divided by the percent of the sample
b. Oxygen depletion during incubation divided by the dilution factor of the incubated sample
c. DO of the raw sample multiplied by the DO of the incubated sample
d. DO of the dilution water divided by the percent sample

3. BOD is the _.
a. Same as oxygen-consuming capacity
b. Amount of carbonaceous matter present
c. Oxygen required during the stabilization of decomposable matter by aerobic bacterial action
d. Ration of the available DO to the oxygen demand

4. What is the minimum DO uptake that will produce the most reliable result for the BOD test?
a. 0.2 mg/L
b. 1.0 mg/L
c. 2.0 mg/L
d. 2.5 mg/L

5. A 300 ml BOD bottle containing 15 ml of sample with an initial dissolved oxygen of 8.2 mg/L is incubated for 5 days. After incubation the dissolved oxygen is 4.7 mg/L. What is the BOD of this sample?
a. 20 mg/L
b. 3.5 mg/L
c. 52.5 mg/L
d. 70 mg/L

Answers:

1. C
2. B
3. A
4. C
5. D
BOD mg/L = 8.2-4.7 X [300mL÷15ml] = (3.5) X (300) ÷ 15 = 70