1
Texas Wastewater Class A Questions with Answers
(100% Correct Answers)
Seeding of BOD samples is necessary when samples— Answer: (All of
the above) have a chlorine residual, have a previously been
chlorinated, have been subjected to high temperatures, contain high or
low pH industrial wastes
When is blue-green algae the most dominant on a pond treatment
system?— Answer: Summer
A 30-inch diameter wastewater interceptor is observed to be flowing
half-full at about two fps. The approximate volume of wastewater
flowing through the pipe is 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 = 2,200
gpm— Answer: c. 2,200 gallons per minute
A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-
inch stroke pumps at a rate of 50 cycles per minute. How many
minutes must the pump be operated to pump 5,000 gallons of sludge?
3.14x0.416 x 0.416 x0.416 x 50 x7.48 = 84.5 gpm 5000 gal = 59,2min 84.5
gpm b. 29— Answer: 60 minutes
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,2
If an existing centrifugal pump motor is replaced with a motor with 25
percent more speed, the motor horsepower required will increase by
1.25 x 1.25 x 1.25 = 1.95— Answer: 95 percent
When must TCEQ be notified about expansions of a treatment
facility?— Answer: Before construction
In an anaerobic digester, the percentage of methane and carbon
dioxide gas content should be— Answer: 70% methane, 30% carbon
dioxide
The temperature of an anaerobic digester should be maintained at a
minimum of— Answer: 95° F
What type of wastewater treatment operates in the endogenous
bacteria growth phase?— Answer: Extended air
Why is recirculation needed in a trickling filter?— Answer: Keep the
media wet Further reduce BOD All of the above (a, b, and c)
What type of fire extinguisher would be used on an electrical control
panel that has been de-energized?— Answer: Class A Class C (a and
d)
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, 3
Disinfection with chlorine is the most effective at a pH of— Answer:
6.0
The biomass on a normal functioning RBC has what appearance?—
Answer: Grey to brown and 0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids?— Answer:
4% to 6%
What is eutrophication in a pond system?— Answer: Enrichment with
nitrogen and phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated?— Answer: Daily
In Texas, pH meters are required to be calibrated on how many
buffers?— Answer: two
An industrial complex has a BOD discharge to the POTW of 500
pounds per day. The population equivalent of this industry is 500 lbs =
2,941 0.17 lbs BOD person— Answer: 2941
The parameters of the BOD test are— Answer: 5 days at 20°
Centigrade
© 2025 All rights reserved
Texas Wastewater Class A Questions with Answers
(100% Correct Answers)
Seeding of BOD samples is necessary when samples— Answer: (All of
the above) have a chlorine residual, have a previously been
chlorinated, have been subjected to high temperatures, contain high or
low pH industrial wastes
When is blue-green algae the most dominant on a pond treatment
system?— Answer: Summer
A 30-inch diameter wastewater interceptor is observed to be flowing
half-full at about two fps. The approximate volume of wastewater
flowing through the pipe is 3.14x1.25 x 1.25 x 2 = 4.9 cfs x 449 = 2,200
gpm— Answer: c. 2,200 gallons per minute
A one-cylinder reciprocating sludge pump with a 10-inch bore and a 5-
inch stroke pumps at a rate of 50 cycles per minute. How many
minutes must the pump be operated to pump 5,000 gallons of sludge?
3.14x0.416 x 0.416 x0.416 x 50 x7.48 = 84.5 gpm 5000 gal = 59,2min 84.5
gpm b. 29— Answer: 60 minutes
© 2025 All rights reserved
,2
If an existing centrifugal pump motor is replaced with a motor with 25
percent more speed, the motor horsepower required will increase by
1.25 x 1.25 x 1.25 = 1.95— Answer: 95 percent
When must TCEQ be notified about expansions of a treatment
facility?— Answer: Before construction
In an anaerobic digester, the percentage of methane and carbon
dioxide gas content should be— Answer: 70% methane, 30% carbon
dioxide
The temperature of an anaerobic digester should be maintained at a
minimum of— Answer: 95° F
What type of wastewater treatment operates in the endogenous
bacteria growth phase?— Answer: Extended air
Why is recirculation needed in a trickling filter?— Answer: Keep the
media wet Further reduce BOD All of the above (a, b, and c)
What type of fire extinguisher would be used on an electrical control
panel that has been de-energized?— Answer: Class A Class C (a and
d)
© 2025 All rights reserved
, 3
Disinfection with chlorine is the most effective at a pH of— Answer:
6.0
The biomass on a normal functioning RBC has what appearance?—
Answer: Grey to brown and 0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids?— Answer:
4% to 6%
What is eutrophication in a pond system?— Answer: Enrichment with
nitrogen and phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated?— Answer: Daily
In Texas, pH meters are required to be calibrated on how many
buffers?— Answer: two
An industrial complex has a BOD discharge to the POTW of 500
pounds per day. The population equivalent of this industry is 500 lbs =
2,941 0.17 lbs BOD person— Answer: 2941
The parameters of the BOD test are— Answer: 5 days at 20°
Centigrade
© 2025 All rights reserved
