1. Which of the following is not one of the four important physical variables that control the performance of a wet air oxidation unit?
a. temperature
b. air supply
c. type of sludge
d. feed solids concentration
e. pressure

2. Which of the following is not an advantage of using heat treatment on sludge?
a. it produces a readily dewaterable sludge
b. it releases water and some organic matter from the sludge
c. it disinfects the sludge
d. it is simple to operate and easy to maintain

3. What 2 factors indicate what a filter press cycle is completed?
a. small filtrate discharge; increased pump pressure
b. increased filtrate discharge; increased pump pressure
c. small filtrate discharge; decreased pump pressure
d. small filtrate discharge; near consultant pump pressure

4. Of the various types of trickling filter media listed below, which one has the highest specific surface area per cubic foot and is therefore capable of the highest hydraulic loading and organic loading?
a. granite rock
b. redwood media
c. plastic media
d. blast furnace slag

5. Which of the following may cause a rise in the mixed liquor dissolved oxygen?
a. a decrease in the influent BOD
b. a toxic chemical which killed the microorganisms
c. an increase in blower speed
d. all the above
e. none of the above

Answers:

1. c

2. b

3. a

4. c

5. d