TEXAS WASTEWATER CLASS A EXAM
QUESTIONS AND ANSWERS. VERIFIED
2026.
Seeding of BOD samples is necessary when samples - ANS (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? - ANS 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 - ANS 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 - ANS 60 minutes
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 - ANS 95 percent
When must TCEQ be notified about expansions of a treatment facility? - ANS Before
construction
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be -
ANS 70% methane, 30% carbon dioxide
The temperature of an anaerobic digester should be maintained at a minimum of - ANS 95° F
What type of wastewater treatment operates in the endogenous bacteria growth phase? -
ANS Extended air
Why is recirculation needed in a trickling filter? - ANS 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? - ANS Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of - ANS 6.0
The biomass on a normal functioning RBC has what appearance? - ANS Grey to brown and
0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids? - ANS 4% to 6%
What is eutrophication in a pond system? - ANS Enrichment with nitrogen and phosphorous
Causes algae blooms (b and c)
How often should pH meters be calibrated? - ANS Daily
In Texas, pH meters are required to be calibrated on how many buffers? - ANS 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 - ANS 2941
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, The parameters of the BOD test are - ANS 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as - ANS Ratio of OD pipe diameter to wall
thickness
How should shoring be removed from a trench? - ANS up from the bottom up
In low pressure sewer systems where each tap must have a grinder pump lift station, station is
considered to be - ANS part of the collection system and the responsibility of the utility
Effective communication depends on - ANS being a good listener
When designing a wastewater collection system, the engineer considers the population for how
many years in the future? - ANS 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a
minimum psi pressure rating of - ANS 150
The minimum velocity of flow in a wastewater line should be - ANS 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between cones and
barricades should - ANS increase
The major cause of wastewater line stoppages is - ANS roots and grease
Carbon monoxide (CO) poisoning symptoms are - ANS tightness in the chest nausea
drowsiness and headache (all of the above)
The smallest pipe size for air recirculation of a self-priming centrifugal pump is - ANS 1 inch
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
QUESTIONS AND ANSWERS. VERIFIED
2026.
Seeding of BOD samples is necessary when samples - ANS (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? - ANS 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 - ANS 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 - ANS 60 minutes
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 - ANS 95 percent
When must TCEQ be notified about expansions of a treatment facility? - ANS Before
construction
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be -
ANS 70% methane, 30% carbon dioxide
The temperature of an anaerobic digester should be maintained at a minimum of - ANS 95° F
What type of wastewater treatment operates in the endogenous bacteria growth phase? -
ANS Extended air
Why is recirculation needed in a trickling filter? - ANS 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? - ANS Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of - ANS 6.0
The biomass on a normal functioning RBC has what appearance? - ANS Grey to brown and
0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids? - ANS 4% to 6%
What is eutrophication in a pond system? - ANS Enrichment with nitrogen and phosphorous
Causes algae blooms (b and c)
How often should pH meters be calibrated? - ANS Daily
In Texas, pH meters are required to be calibrated on how many buffers? - ANS 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 - ANS 2941
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, The parameters of the BOD test are - ANS 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as - ANS Ratio of OD pipe diameter to wall
thickness
How should shoring be removed from a trench? - ANS up from the bottom up
In low pressure sewer systems where each tap must have a grinder pump lift station, station is
considered to be - ANS part of the collection system and the responsibility of the utility
Effective communication depends on - ANS being a good listener
When designing a wastewater collection system, the engineer considers the population for how
many years in the future? - ANS 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a
minimum psi pressure rating of - ANS 150
The minimum velocity of flow in a wastewater line should be - ANS 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between cones and
barricades should - ANS increase
The major cause of wastewater line stoppages is - ANS roots and grease
Carbon monoxide (CO) poisoning symptoms are - ANS tightness in the chest nausea
drowsiness and headache (all of the above)
The smallest pipe size for air recirculation of a self-priming centrifugal pump is - ANS 1 inch
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
