1. What is a typical reduction in volume when dewatered sludge is incinerated?
a. 20 – 30%
b. 35 – 50%
c. 55 – 79%
d. 80 – 90%

2. What sludge does air floatation typically treat?
a. primary
b. waste activated
c. digested anaerobic

3. Which pump is best for pumping chemicals?
a. positive displacement
b. centrifugal
c. screw
d. airlift

4. Ozone is a good disinfection because _.
a. it is cheap and easy to produce
b. small amount can kill any bacteria
c. it forms less carcinogenic compounds when it reacts with wastewater than other disinfectants
d. it has a metallic odor

5. A belt filter press is processing secondary sludge. Some of the sludge is squeezing out from between the belts adn contaminating the effluent by falling out into the filtrate trays. How could this problem be corrected?
a. blend primary sludge with the secondary sludge
b. build baffles around the belt
c. chlorinate the effluent
d. filter the effluent
e. move the filtrate trays

Answers:

1. d
2. b
3. a
4. c
5. a