Wastewater Operator 4 test prep| 300 questions|
with complete solutions
Heterotrophic Correct Answer: uses organic compounds (BOD) for their carbon source
Autotrophic Correct Answer: · use CO2 as their carbon source
· Makes own food
· nitrifiers
· Use alkalinity as carbon source
· Convert ammonia to nitrite and nitrate
· Redox potential of +200
Bacteria shape round Correct Answer: cocci
Bacteria shape rods Correct Answer: bacilli
Bacteria shape spiral Correct Answer: spirilla
· Freely dispersed bacteria Correct Answer: o often don't settle and leave as TSS
o favor high organic load
o favor low dissolved oxygen
· Floc forming bacteria Correct Answer: o Stick together and settle out
o Degrade BOD
· Filamentous bacteria Correct Answer: o Caused by low DO
Protazoa Correct Answer: single cell
Metazoa Correct Answer: multi-cell
Does Heterotrophic or Autotrophic use organic compounds (BOD) for their carbon source
Correct Answer: heterotrophic
Does Heterotrophic or Autotrophic use CO2 as their carbon source Correct Answer: Autotrophic
Does Heterotrophic or Autotrophic make own food Correct Answer: Autotrophic
Are Heterotrophic or Autotrophic nitrifiers Correct Answer: Autotrophic
Does Heterotrophic or Autotrophic use alkalinity as carbon source Correct Answer: Autotrophs
Does Heterotrophic or Autotrophic Convert ammonia to nitrite and nitrate Correct Answer:
Autotrophs
,Does Heterotrophic or Autotrophic have Redox potential of +200 Correct Answer: Autotrophs
Bacteria shape Round Correct Answer: cocci
Bacteria shape rods Correct Answer: bacilli
Bacteria shape Spiral Correct Answer: spirilla
What are the 3 types of bacteria Correct Answer: Freely dispersed, floc forming and filamentous
Which 2 types of bacteria come from low DO Correct Answer: Freely dispersed and filamentous
Which type of bacteria comes from high organic load Correct Answer: Freely dispersed
Which types of bacteria don't settle well Correct Answer: Freely dispersed and filamentous
Which type of bacteria degrades BOD Correct Answer: Floc forming
What is the pH preference of bacteria Correct Answer: 7 to 9
What is the temperature preference of bacteria Correct Answer: 60-70F
What is the primary cause of non-compliance in plants Correct Answer: Filamentous bulking
What is Bulking Correct Answer: settles and compacts slowly
At what SVI is it considered bulking Correct Answer: above 150
What are 2 things you can add to help with sludge bulking Correct Answer: Chlorinate the
return sludge or adding flocculant can help.
Sludge bulking could be caused by a high or low DO Correct Answer: low
Sludge bulking could be caused by a high or low F/M Correct Answer: low
Sludge bulking could be caused by a high or low pH Correct Answer: low
Sludge bulking could be caused by high or low nutrients Correct Answer: Low
Sludge bulking could be caused by high or low SRT Correct Answer: low
Sludge bulking could be caused by Correct Answer: Low DO, Low F/M, Low pH, Low nitrogen
or phosphorous, low SRT
What kind of bacteria might we see if there is excessive grease and oil Correct Answer: nocardia
, What is a good BOD:N:P ratio for BOD removal Correct Answer: 100:5:1
What is a good BOD:N:P ratio for nutrient removal Correct Answer: 100:20:2
What are 3 causes foam that is Thin, white to grey Correct Answer: low cell residence time,
young sludge, soluble BOD breaking through
What causes foam that is white, frothy, billowing Correct Answer: non-biodegradable
detergents. Rare now
What causes foam that is pumice-like, ashing, grey foam Correct Answer: excessive fine recycle
from other processes (anaerobic digester)
What causes foam that is thick, pasty or slimy, gray foam Correct Answer: nutrient deficient
What causes the most common foam which is thick, brown foam Correct Answer: filament
induced foam, nocardia or Microthrix
How to remove risk of Norcardia and Parvicella Correct Answer: both like low DO and long
sludge ages (ie shorten sludge age if have)
Norcardia favors high or low temperatures Correct Answer: high
Parvicella favors high or low temperatures Correct Answer: low
What is a common holding time for Sampling for Ammonia, COD, nitrate-nitrite, oil/grease,
phenols, phosphorus, TKN Correct Answer: 28 days
What is a common preservation temperature for Sampling for Ammonia, COD, nitrate-nitrite,
oil/grease, phenols, phosphorus, TKN Correct Answer: 4 deg C
What holding time and preservation for Disinfectant sampling Correct Answer: 15 minute max
holding time, no preservation
What is an ideal pH to preserve a sample of Hydrogen Sulfide H2SO4 Correct Answer: pH less
than 2
BOD testing uses what size bottle Correct Answer: 300mL
BOD testing is at what temperature, for how many days, and how much light Correct Answer:
20deg C for 5 days with no light
What are the 2 parameters logged in BOD testing Correct Answer: DO vs time
Why would you choose COD testing over BOD testing Correct Answer: Results available
sooner and more precise/accurate
with complete solutions
Heterotrophic Correct Answer: uses organic compounds (BOD) for their carbon source
Autotrophic Correct Answer: · use CO2 as their carbon source
· Makes own food
· nitrifiers
· Use alkalinity as carbon source
· Convert ammonia to nitrite and nitrate
· Redox potential of +200
Bacteria shape round Correct Answer: cocci
Bacteria shape rods Correct Answer: bacilli
Bacteria shape spiral Correct Answer: spirilla
· Freely dispersed bacteria Correct Answer: o often don't settle and leave as TSS
o favor high organic load
o favor low dissolved oxygen
· Floc forming bacteria Correct Answer: o Stick together and settle out
o Degrade BOD
· Filamentous bacteria Correct Answer: o Caused by low DO
Protazoa Correct Answer: single cell
Metazoa Correct Answer: multi-cell
Does Heterotrophic or Autotrophic use organic compounds (BOD) for their carbon source
Correct Answer: heterotrophic
Does Heterotrophic or Autotrophic use CO2 as their carbon source Correct Answer: Autotrophic
Does Heterotrophic or Autotrophic make own food Correct Answer: Autotrophic
Are Heterotrophic or Autotrophic nitrifiers Correct Answer: Autotrophic
Does Heterotrophic or Autotrophic use alkalinity as carbon source Correct Answer: Autotrophs
Does Heterotrophic or Autotrophic Convert ammonia to nitrite and nitrate Correct Answer:
Autotrophs
,Does Heterotrophic or Autotrophic have Redox potential of +200 Correct Answer: Autotrophs
Bacteria shape Round Correct Answer: cocci
Bacteria shape rods Correct Answer: bacilli
Bacteria shape Spiral Correct Answer: spirilla
What are the 3 types of bacteria Correct Answer: Freely dispersed, floc forming and filamentous
Which 2 types of bacteria come from low DO Correct Answer: Freely dispersed and filamentous
Which type of bacteria comes from high organic load Correct Answer: Freely dispersed
Which types of bacteria don't settle well Correct Answer: Freely dispersed and filamentous
Which type of bacteria degrades BOD Correct Answer: Floc forming
What is the pH preference of bacteria Correct Answer: 7 to 9
What is the temperature preference of bacteria Correct Answer: 60-70F
What is the primary cause of non-compliance in plants Correct Answer: Filamentous bulking
What is Bulking Correct Answer: settles and compacts slowly
At what SVI is it considered bulking Correct Answer: above 150
What are 2 things you can add to help with sludge bulking Correct Answer: Chlorinate the
return sludge or adding flocculant can help.
Sludge bulking could be caused by a high or low DO Correct Answer: low
Sludge bulking could be caused by a high or low F/M Correct Answer: low
Sludge bulking could be caused by a high or low pH Correct Answer: low
Sludge bulking could be caused by high or low nutrients Correct Answer: Low
Sludge bulking could be caused by high or low SRT Correct Answer: low
Sludge bulking could be caused by Correct Answer: Low DO, Low F/M, Low pH, Low nitrogen
or phosphorous, low SRT
What kind of bacteria might we see if there is excessive grease and oil Correct Answer: nocardia
, What is a good BOD:N:P ratio for BOD removal Correct Answer: 100:5:1
What is a good BOD:N:P ratio for nutrient removal Correct Answer: 100:20:2
What are 3 causes foam that is Thin, white to grey Correct Answer: low cell residence time,
young sludge, soluble BOD breaking through
What causes foam that is white, frothy, billowing Correct Answer: non-biodegradable
detergents. Rare now
What causes foam that is pumice-like, ashing, grey foam Correct Answer: excessive fine recycle
from other processes (anaerobic digester)
What causes foam that is thick, pasty or slimy, gray foam Correct Answer: nutrient deficient
What causes the most common foam which is thick, brown foam Correct Answer: filament
induced foam, nocardia or Microthrix
How to remove risk of Norcardia and Parvicella Correct Answer: both like low DO and long
sludge ages (ie shorten sludge age if have)
Norcardia favors high or low temperatures Correct Answer: high
Parvicella favors high or low temperatures Correct Answer: low
What is a common holding time for Sampling for Ammonia, COD, nitrate-nitrite, oil/grease,
phenols, phosphorus, TKN Correct Answer: 28 days
What is a common preservation temperature for Sampling for Ammonia, COD, nitrate-nitrite,
oil/grease, phenols, phosphorus, TKN Correct Answer: 4 deg C
What holding time and preservation for Disinfectant sampling Correct Answer: 15 minute max
holding time, no preservation
What is an ideal pH to preserve a sample of Hydrogen Sulfide H2SO4 Correct Answer: pH less
than 2
BOD testing uses what size bottle Correct Answer: 300mL
BOD testing is at what temperature, for how many days, and how much light Correct Answer:
20deg C for 5 days with no light
What are the 2 parameters logged in BOD testing Correct Answer: DO vs time
Why would you choose COD testing over BOD testing Correct Answer: Results available
sooner and more precise/accurate
