Colorado WW Operator D EXAM 2026-2027
ACTUAL COMPLETE REAL EXAM QUESTIONS WITH
COMPLETE VERIFIED SOLUTION GUIDE (A+
GRADED 100% ACCURATE) 2025 NEWEST
VERSION!!
_ _____ = flow, mgd x chlorine dosage, mg/L x 8.34 lb/gal.
ANSWERS: Feed Rate/Dose (lbs/day)
Sodium hypochlorite is manufactured by the reaction of gaseous or liquid
chlorine with a solution of to produce a liquid containing NaOCl.
ANSWERS: Sodium hypochlorite
At concentrations less than , chlorine gas is not detectable by the human
sense
of smell.
ANSWERS: 1 ppm
,A treatment plant uses sulfur dioxide to dechlorinate effluent. An operator
needs to adjust the sulfonator so that the dosing concentration is 1.5 mg/l
more than the chlorine residual. Based on the following information, what
should the sulfonator feed rate be: design flow = 5 mgd; chlorine dosage
rate = 4 mg/l; chlorine residual
= 0.9 mg/l
ANSWERS: 100 lb/day
The UV dose represents the product of the rate of energy emission (lamp
intensity) and the time the organisms are exposed to the germicidal energy
at 254 nm. This can be expressed by the equation:
ANSWERS: Dose = intensity x time (d=It)
The amount of chlorine used per day from a 1 ton cylinder is normally
determined by
ANSWERS: Weighings
Ultraviolet disinfection is becoming more popular because UV systems
ANSWERS: Eliminate safety concerns about handling chlorine
,If a 100-mgd flow of wastewater is dosed at a rate of 12 mg/l, what
should the chlorine-reed setting be to the nearest 100 lb/d?
ANSWERS: 10,000
Coliform bacteria are:
ANSWERS: More resistant to chlorination than pathogenic bacteria
After chlorine, what is the most common effluent wastewater disinfection
technique or agent used in the US today?
ANSWERS: Ultraviolet radiation
Calculate the chlorine demand given: flow rate = 120 mgd; chlorine feed rate =
8000 lb/d; chlorine residual = 1.0 mg/l after contact time.
ANSWERS: 7 ppd
The fusible plug on a chlorine cylinder melts at aboutdegrees.
ANSWERS: 150 - 162
One volume of liquid chlorine will yield about volumes of chlorine gas.
ANSWERS: 450
, The two qualities in a final effluent that most affect performance of
ultraviolet disinfection system are UV transmission and _.
ANSWERS: Suspended Solids
Which of the following would be the safest action to take in the event of a
major chlorine container leak?
ANSWERS: Call the fire department
_ _ (which can be used for disinfection) may be mechanically produced by
photochemical or electrical methods resembling the natural processes.
ANSWERS: Ozone, O3
The destruction of the larger portion of microorganisms with the probability
that all pathogens are killed is called
ANSWERS: Disinfection
Chlorine gas is _ times heavier than air.
ANSWERS: 2.5
The fusible plug on a chlorine cylinder melts at aboutdegrees.
ANSWERS: 150 - 162
ACTUAL COMPLETE REAL EXAM QUESTIONS WITH
COMPLETE VERIFIED SOLUTION GUIDE (A+
GRADED 100% ACCURATE) 2025 NEWEST
VERSION!!
_ _____ = flow, mgd x chlorine dosage, mg/L x 8.34 lb/gal.
ANSWERS: Feed Rate/Dose (lbs/day)
Sodium hypochlorite is manufactured by the reaction of gaseous or liquid
chlorine with a solution of to produce a liquid containing NaOCl.
ANSWERS: Sodium hypochlorite
At concentrations less than , chlorine gas is not detectable by the human
sense
of smell.
ANSWERS: 1 ppm
,A treatment plant uses sulfur dioxide to dechlorinate effluent. An operator
needs to adjust the sulfonator so that the dosing concentration is 1.5 mg/l
more than the chlorine residual. Based on the following information, what
should the sulfonator feed rate be: design flow = 5 mgd; chlorine dosage
rate = 4 mg/l; chlorine residual
= 0.9 mg/l
ANSWERS: 100 lb/day
The UV dose represents the product of the rate of energy emission (lamp
intensity) and the time the organisms are exposed to the germicidal energy
at 254 nm. This can be expressed by the equation:
ANSWERS: Dose = intensity x time (d=It)
The amount of chlorine used per day from a 1 ton cylinder is normally
determined by
ANSWERS: Weighings
Ultraviolet disinfection is becoming more popular because UV systems
ANSWERS: Eliminate safety concerns about handling chlorine
,If a 100-mgd flow of wastewater is dosed at a rate of 12 mg/l, what
should the chlorine-reed setting be to the nearest 100 lb/d?
ANSWERS: 10,000
Coliform bacteria are:
ANSWERS: More resistant to chlorination than pathogenic bacteria
After chlorine, what is the most common effluent wastewater disinfection
technique or agent used in the US today?
ANSWERS: Ultraviolet radiation
Calculate the chlorine demand given: flow rate = 120 mgd; chlorine feed rate =
8000 lb/d; chlorine residual = 1.0 mg/l after contact time.
ANSWERS: 7 ppd
The fusible plug on a chlorine cylinder melts at aboutdegrees.
ANSWERS: 150 - 162
One volume of liquid chlorine will yield about volumes of chlorine gas.
ANSWERS: 450
, The two qualities in a final effluent that most affect performance of
ultraviolet disinfection system are UV transmission and _.
ANSWERS: Suspended Solids
Which of the following would be the safest action to take in the event of a
major chlorine container leak?
ANSWERS: Call the fire department
_ _ (which can be used for disinfection) may be mechanically produced by
photochemical or electrical methods resembling the natural processes.
ANSWERS: Ozone, O3
The destruction of the larger portion of microorganisms with the probability
that all pathogens are killed is called
ANSWERS: Disinfection
Chlorine gas is _ times heavier than air.
ANSWERS: 2.5
The fusible plug on a chlorine cylinder melts at aboutdegrees.
ANSWERS: 150 - 162
