1. The most important reason for chlorinating effluent samples is _.
a. Decreasing BOD levels and controlling odors
b. Improving scum and grease removal and chemical coagulation
c. Disinfection
d. Decreasing SS levels

2. The chlorine residual may be determined using the reagent _.
a. DPD
b. EDTA
c. PCBs
d. Sodium thiosulfate

3. When collecting samples for bacteriological examination, Sodium thiosulfate (Na2S2O3) is used to _.
a. Buffer the pH to 7.0
b. Buffer the pH to 8.5
c. Oxidize the residual chlorine
d. Reduce the residual chlorine

4. When reporting bacteria results in wastewater, they are reported as _.
a. MPN or CFU/ml
b. MPN or CFU/gram
c. MPN or CFU/mgd
d. MPN or CFU/100 ml

5. What is the desired number of total coliform colonies on a membrane filtration plate when determining bacteria populations?
a. 1 to 40
b. 6 to 75
c. 20 to 80
d. 20 to 100

Answers:

1. C
2. A
3. D
4. D
5. C