1. Characteristics that should be measured immediately after the sample is collected are _.
a. Velocity and dissolved solids
b. Temperature, pH and DO
c. Sulfur, iron and copper
d. Hardness and alkalinity

2. The best method for collecting residual chlorine samples is _.
a. Grab samples during the day
b. Composite samples made up of 24-hour portions, each taken in equal volumes for 24-hrs
c. Composite samples made up of 24-hr portions, each taken proportionally to the flow at the time taken, for 24-hrs
d. A composite sample of the contact chamber influent and effluent

3. Composite samples are collected because _.
a. The waste characteristics are continually changing
b. The flow is continually changing
c. The flow and characteristics of the waste are continually changing
d. This requires less time than grab samples

4. Composite samples for BOD tests could be preserved by _.
a. 10-ml chloroform
b. Refrigeration
c. 10-ml nitric acid
d. 10-ml formaldehyde

5. In sampling wastewater for a BOD test, the best results are obtained from _.
a. A 24-hr composite sample
b. A grab sample
c. A sample made of 2 to 4 portions taken at time of high flow
d. A sample taken at time of low flow

Answers:

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