Wastewater C Exam 2019 Study Guide Flashcards
1) You suspect your anaerobic digester is going sour, what is the best way to verify its condition?
VA/ALK Ratio
2) What is considered normal operation of an aerobic digester?
Settle and Decant as needed
3) What growth phase is an aerobic digester operated in?
Endogenous Respiration
4) Low DO and nutrient deficiency will promote the growth of what?
Filamentous Bacteria
5) If you pump green sludge to a drying bed, what chemical should be applied?
Lime
6) Chlorine leaks can be detected by?
Ammonia solution with Q-tip
7) Why is an aerobic digester covered?
To protect from cold weather
8) What takes place in the stabilization tank in a contact stabilization plant?
Absorption
9) Why would you chlorinate the RAS line?
To control filamentous bacteria
10) What is the most common type of pond?
Facultative
11) Denitrification will cause what?
Rising sludge
12) How does the temperature effect disinfection?
Higher the temperature the greater the disinfection
13) How long should you wait after you make a process change before making another change?
1 Week
14) What is needed to calculate the F/M ratio?
BOD in Ibs and MLVSS in Ibs
15) What type of ponds are used after a trickling filter?
Polishing pond
16) You have excessive billowing, white, sudsy foam on the surface of the aerator. What is the cause?
F/M is too high
17) Chlorine is not coming out. Another cylinder is hooked up with the same problem occurring. What is the problem?
Manifold line is clogged
18) What would cause the most damage to a centrifugal pump?
Cavitation
19) Coliform bacteria are used for what?
Indicators of possible presence of pathogenic organisms
20) It can be said that:
The lower the PH, the greater the disinfection
21) What is the disadvantage of a hypo chlorinator?
Increases the PH and decreases the disinfection
22) What 2 stages are in an anaerobic digester?
Acid formation and gas formation
23) What is the benefit of step-feed aeration?
Treat higher flows in less space
24) What are the 2 main gases produced by an anaerobic digester?
Methane and CO2
25) When working in a manhole, what would be the biggest danger?
Asphyxiation
26) What are some similarities between Methane and H2S?
Flammable, explosive, colorless
27) What causes the most wear to an impeller?
Grit
28) What is a true statement about recording data?
There are many ways to record data
29) Short circuiting in a primary clarifier can be prevented by?
Baffles
30) What do you do if you experience a plant upset due to hydraulic overload?
Decrease WAS to maintain microorganism population
31) You have dark foam, High MLSS, slow settling sludge with a clear effluent, you should?
Maintain 1-3 foot sludge blanket, monitor MLSS, increase DO if necessary
32) The PH in your plant is decreasing, effluent turbidity is increasing, and sludge is rising in the clarifier.
What is the problem?
Denitrification
33) How do you calculate the F/M ratio?
Influent COD Ibs, divided by the MLVSS in Ibs
34) A good settling sludge would consist of what type of Protozoa?
Free swimmers and stalked ciliates
35) Low DO and nutrient deficiency will promote the growth of what?
Filamentous bacteria
36) Coliform count fails to meet the standards and your chlorine supply is not the problem. What is?
Short circuiting and low contact time
37) The Settleometer settles fairly slowly. You have shiny, dark foam on the surface of the aerator. What
is the problem?
MCRT too high
38) CI2 combined with ammonia forms what?
Chloramines
39) What is the best range of parameters for the Activated Sludge process?
2mg/L DO, PH 7.0, 80-90 Temp
40) What can happen if more than 40lbs of chlorine is withdrawn from a 150lb tank in a 24 hour period?
Freezing of the lines
41) The TSS of the digester supernatant should be calculated because?
To measure the solids load on the plant
42) The first step in anaerobic digestion is?
Acid formation
43) The correct way to break up an overloaded blanket in an anaerobic digester is?
Spray down the blanket
44) Chapter code 699/ What is staffing based on?
Flow and type of treatment
45) What is one of the most dangerous gases in the plant?
Hydrogen sulfide
46) What causes white foam?
Low MLSS
47) What causes sludge bulking?
Filaments
48) What can cause rancid or nasty butter smelling supernatant in an anaerobic digester?
Toxic shock load
49) Which of the following are not protozoa?
Nematodes
50) If you see dead spots in the aeration tank what is the cause?
Lack of air/blocked diffuser pipe
51) If you have Filament bulking what do you check?
SVI
52) What do use on an electrical fire?
Carbon Dioxide
53) What is a trend?
Increase or decrease in the same direction
54) What is an Aliquot?
Representation of a sample
55) Pump impeller provide what end of suction piping with a screen?
Intake end
56) Digesters should be cleaned every?
5 Years or 3-8 Years
57) When mixing Acid and water you should always?
Add acid to water, never the reverse
58) Chlorine cylinders should be stored?
In the upright position
59) What is the velocity in a grit channel?
1 foot per second
60) What prevents explosions if excessive pressure builds up in a chlorine tank?
Fusible plug
61) The distance between manholes is?
300-500 Feet
62) Normal operation of a centrifugal pump?
One drip per second
63) What will cause an operator to permanently loose licensure?
Gross negligence
64) Chapter 62-620 FAC : Plant records must be kept onsite for how many years?
3 years
65) What causes dark sudsy foam on the aeration tank surface?
Low DO levels
66) What is highly corrosive in the presence of moisture, respiratory irritant, irritation to the eyes, skin
and mucus membrane?
Sulfur dioxide
67) What type of positive displacement pump should never be operated against a closed discharge
valve, pipe could be damaged by excessive pressure?
Piston pump
68) What is the first step in anaerobic digestion?
Acid formation
69) When is the best time to return supernatant from an aerobic digester to the plant?
During high flows
70) What is a mixture of two or more liquids (one suspended in the other) called?
Emulsion
71) Which organisms will thrive if the DO in the aeration tank is too low?
Filamentous organisms
72) Bubbles are attaching to floc and floating it to the surface, what is the cause?
Denitrification
73) What is the proper ratio of nutrients in domestic wastewater (BOD:Nitrogen:Phosphorus:Iron)?
100:5:1:0.5
74) Where should samples be taken in a conventional activated sludge plant?
At the effluent end of the aerator
75) What is “riprap” used for?
To protect against erosion
76) What can be caused by over aeration?
Floc shearing
77) Which of the following would be the best VA/ALK ratio?
0.1:1.0
78) What is it called when nitrate is reduced to nitrogen gas?
Denitrification
79) Which organisms will predominate when the F/M ratio is low?
Rotifers
80) What should you do in low temperatures if complete nitrification is required?
Increase MLSS
81) In a properly operating facultative pond, algae live on carbon dioxide and nutrients during the day,
and at night produce carbon dioxide. This has what effect on PH?
PH increases during the day and
decreases at night
82) How can a sour digester be recovered?
Add lime or seed sludge from another plant