Texas Wastewater Class A (Prep for
wastewater class A) questions and answers
2025\2026 A+ Grade
Seeding of BOD samples is necessary when samples
- correct 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?
- correct 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
- correct 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
- correct answer 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
- correct answer 95 percent
When must TCEQ be notified about expansions of a treatment facility?
- correct answer Before construction
In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be
- correct answer 70% methane, 30% carbon dioxide
,The temperature of an anaerobic digester should be maintained at a minimum of
- correct answer 95° F
What type of wastewater treatment operates in the endogenous bacteria growth phase?
- correct answer Extended air
Why is recirculation needed in a trickling filter?
- correct 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?
- correct answer Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of
- correct answer 6.0
The biomass on a normal functioning RBC has what appearance?
- correct answer Grey to brown and 0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids?
- correct answer 4% to 6%
What is eutrophication in a pond system?
- correct answer Enrichment with nitrogen and phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated?
- correct answer Daily
In Texas, pH meters are required to be calibrated on how many buffers?
- correct 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
- correct answer 2941
The parameters of the BOD test are
- correct answer 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as
- correct answer Ratio of OD pipe diameter to wall thickness
How should shoring be removed from a trench?
- correct answer 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
- correct answer part of the collection system and the responsibility of the utility
Effective communication depends on
- correct answer being a good listener
When designing a wastewater collection system, the engineer considers the population for how many
years in the future?
- correct answer 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a
minimum psi pressure rating of
- correct answer 150
The minimum velocity of flow in a wastewater line should be
- correct answer 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between cones and barricades
should
- correct answer increase
wastewater class A) questions and answers
2025\2026 A+ Grade
Seeding of BOD samples is necessary when samples
- correct 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?
- correct 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
- correct 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
- correct answer 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
- correct answer 95 percent
When must TCEQ be notified about expansions of a treatment facility?
- correct answer Before construction
In an anaerobic digester, the percentage of methane and carbon dioxide gas content should be
- correct answer 70% methane, 30% carbon dioxide
,The temperature of an anaerobic digester should be maintained at a minimum of
- correct answer 95° F
What type of wastewater treatment operates in the endogenous bacteria growth phase?
- correct answer Extended air
Why is recirculation needed in a trickling filter?
- correct 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?
- correct answer Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of
- correct answer 6.0
The biomass on a normal functioning RBC has what appearance?
- correct answer Grey to brown and 0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids?
- correct answer 4% to 6%
What is eutrophication in a pond system?
- correct answer Enrichment with nitrogen and phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated?
- correct answer Daily
In Texas, pH meters are required to be calibrated on how many buffers?
- correct 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
- correct answer 2941
The parameters of the BOD test are
- correct answer 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as
- correct answer Ratio of OD pipe diameter to wall thickness
How should shoring be removed from a trench?
- correct answer 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
- correct answer part of the collection system and the responsibility of the utility
Effective communication depends on
- correct answer being a good listener
When designing a wastewater collection system, the engineer considers the population for how many
years in the future?
- correct answer 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure shall have a
minimum psi pressure rating of
- correct answer 150
The minimum velocity of flow in a wastewater line should be
- correct answer 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between cones and barricades
should
- correct answer increase
