WASTEWATER TREATMENT
PLANTS (LEVELS 1-2 EXAM PREP)
WITH CORRECT ANSWERS
An Imhoff cone is used to measure________solids.
A. suspended
B. colloidal
C. volatile
D. settleable - CORRECT-ANSWERSD. settleable
(Operation of Wastewater Treatment Plants, Volume 1
by Kenneth D. Kerri)
The function of sodium nitrate, when added to a waste stabilization pond -
CORRECT-ANSWERSSodium nitrate may be used to minimize odor problems
during brief overload conditions in an un-aerated waste stabilization pond.
(pg 31 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
The normal color of a wastewater treatment pond, especially during the
summer months - CORRECT-ANSWERSGreen, due to the growth of algae
near the pond surface
(pg 32 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
typical F/M ratio in the conventional activated sludge process - CORRECT-
ANSWERS.2-.5 F/M
(pg 32 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Excessive tan "greasy" foam can indicate what in the activated sludge
process? - CORRECT-ANSWERSPossible Nocardia infestation
(pg 36 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
,White crispy billowy foam can indicate what in the activated sludge process?
- CORRECT-ANSWERSStart up or recovery from upset condition (low F/M,
young sludge)
(pg 36 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Moderately light brown foam can indicate what in the activated sludge
process? - CORRECT-ANSWERSNormal operation
(pg 36 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Process control test most often used to determine the settling characteristics
of activated sludge - CORRECT-ANSWERSSludge Volume Index (SVI)
(pg 37 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
The loading to an RBC is measured in these units - CORRECT-
ANSWERSPounds of soluble BOD/day/1000 sq ft. of surface area
(pg 38 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Aerobic biological treatment process capable of at least 85% removal of BOD
and total suspended solids. - CORRECT-ANSWERSSecondary treatment
(pg 39 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Microorganisms associated with good quality activated sludge - CORRECT-
ANSWERSfree swimming ciliates and stalked ciliates
(pg 40 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
RBC slime growth that appears white could indicate what? - CORRECT-
ANSWERSExcess sulfide in wastewater promotes growth of sulfur bacteria
Beggiatoa
(pg 45 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
, This chemical, when present in wastewater effluent, can cause serious
interference with disinfection - CORRECT-ANSWERSnitrite, produced during
nitrification, can cause high chlorine demand
(pg 58 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
The most commonly used chemical for effluent dechlorination - CORRECT-
ANSWERSsulfur dioxide
(pg 60 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
The characteristics (values present) of typical domestic raw sewage:
BOD
Suspended Solids
Total Solids - CORRECT-ANSWERSBOD= 150-250 mg/L
Suspended Solids= 175-275 mg/L
Total Solids= 1000 mg/L or .1%
(pg 69 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
The relationship between the COD and BOD levels in raw domestic sewage -
CORRECT-ANSWERSCOD is approximately 2.2 times the BOD content
(pg 69 "Wastewater Treatment Flash CERT!" 2013 second edition, Daniel W.
Lundy)
Standard bottle volume for BOD5 test - CORRECT-ANSWERS300 ml
What should be done if the pH and DO in a wastewater stabilization pond are
dropping dangerously low? - CORRECT-ANSWERSCheck the loading. The
loading may need to be reduced or stopped. Recirculating the water from a
healthy pond to the problem pond should help the situation. Recirculation
from outlet to inlet areas is beneficial for seeding, DO, and mixing.
(question 9.6L, Operation of Wastewater Treatment Plants, Volume 1
by Kenneth D. Kerri)
What factors would you consider when developing an operating strategy for
wastewater stabilization ponds? - CORRECT-ANSWERS1. Maintain constant
water elevations in the ponds