1.  When sludge does not settle properly it is called "sludge bulking".

a.  True b.  False

2.  Which of these indicates poor clarifier performance?

a.  Low pH of wastewater and odors b.  Loss of solids over effluent weir c.  Floating clumps of sludge on water surface d.  All of the Above

3.  Sedimentation and flotation units include:

a.  Clarifiers and Imhoff tanks b.  Aeration tanks c.  Hydrostatic systems d.  All of the Above

4.  A flow of 1,400 GPM is about the same as:

a.  0.33 MGD b.  0.50 MGD c.  1.0 MGD d.  2 MGD e.  3 MGD

5.  If wastewater recirculation rates are too low:

a.  Aerobic conditions may develop in the secondary clarifier b.  Anaerobic conditions may develop in the secondary clarifier

6.  If wastewater recirculation rates are too high:

a.  Solids will wash out of the secondary clarifier b.  Effluent wil be sparkling clear

7.  What best measures the efficiency of a trickling filter?

a.  BOD b.  pH c.  Sludge age d.  Temperature e.  Total solids

8.  To adjust the pH of wastewater in a sedimentation-digestion unit, lime or anhydrous ammonia can be used.

a.  True b.  False

9.  Secondary or final clarifiers do which of the following?

a.  Increase sludge digestion b.  Prevent secondary flocculation from occurring c.  Dampen influent flow surges d.  Are breeding/storage basins for microorganisms e.  Remove biological solids from wastewater

10.  Which of these are dangerous gases that an operator may encounter in and around a treatment plant?

a.  Carbon dioxide b.  Carbon monoxide c.  Chlorine d.  Hydrogen sulfide e.  Methane f.  All of the Above

11.  What is the detention time in a 20,000 gallon sedimentation tank if the flow is 0.25 MGD?

a.  1.5 hr b.  1.9 hr c.  2.0 hr d.  3.3 hr e.  4.2 hr

12.  Loadings on a trickling filter are expressed as

a.  gal/day/sq. ft. and  lb. BOD/day/1,000 cu. ft. b.  gal/day/1,000 cu. ft. and  lb. BOD/day/sq. ft. c.  lb. H20/day/sq. ft

13.  An indication if a trickling filter is poorly or properly working is odors.

a.  True b.  False

14.  To measure if a rotating biological contactor is operating properly an operator should check the following:

a.  BOD b.  Suspended solids c.  pH d.  Dissolved Oxygen e.  All of the Above

15.  Rotating biological contactors are usually covered to:

a.  Protect biological slime growths from freezing b.  Prevent growth of algae on the media c.  Prevent intense rains from washing some of the slime growth off the media d.  All of the Above

16.  Activated sludge contains bacteria, protozoa and rotifiers.

a.  True b.  False

17.  What is the cause of ponding on a trickling filter?

a.  Increase in biological slime growths on media b.  Increase in chlorination dose to the filter c.  Increase in filter ventilation d.  Increase in growths of pathogenic organisms in the filter voids e.  Increase in wastewater distribution over the surface of the media f.  All of the Above

18.  A successful trickling filter operation depends on:

a.  Washing all slimes off the filter media b.  Straining the solids out of the wastewater c.  Prevent sludge bulking d.  Maintenance of a good growth of organisms on the filter media e.  Maintenance of a chlorine residual in the effluent

19.  A low solid content in the aerator is indicated by white, fluffy foam and a high solid content is indicated by brown, leathery foam.

a.  True b.  False

20.  What does Activated sludge process mean?

a.  Activated air is used in the process b.  The plant must be activated before the wastewater is treated c.  Activated carbon is used in the process d.  The sludge particles are teeming with bacteria, fungi and protozoa e.  The microorganisms must be activated before they start treating the wastewater

21.  A package activated sludge plant does not include a clarifier.

a.  True b.  False

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