Texas Wastewater Class A Test Questions and
Answers With Complete Solution
Seeding of BOD samples is necessary when samples - (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? - 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 - 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 - 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 - 95
percent
When must TCEQ be notified about expansions of a treatment facility? - Before
construction
In an anaerobic digester, the percentage of methane and carbon dioxide gas content
should be - 70% methane, 30% carbon dioxide
The temperature of an anaerobic digester should be maintained at a minimum of -
95° F
What type of wastewater treatment operates in the endogenous bacteria growth
phase? - Extended air
Why is recirculation needed in a trickling filter? - 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? - Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of - 6.0
, The biomass on a normal functioning RBC has what appearance? - Grey to brown and
0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids? - 4% to 6%
What is eutrophication in a pond system? - Enrichment with nitrogen and
phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated? - Daily
In Texas, pH meters are required to be calibrated on how many buffers? - 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 - 2941
The parameters of the BOD test are - 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as - Ratio of OD pipe diameter to
wall thickness
How should shoring be removed from a trench? - 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 - part of the collection system and the responsibility of the
utility
Effective communication depends on - being a good listener
When designing a wastewater collection system, the engineer considers the
population for how many years in the future? - 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure
shall have a minimum psi pressure rating of - 150
The minimum velocity of flow in a wastewater line should be - 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between
cones and barricades should - increase
The major cause of wastewater line stoppages is - roots and grease
Carbon monoxide (CO) poisoning symptoms are - 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 - 1
inch
Answers With Complete Solution
Seeding of BOD samples is necessary when samples - (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? - 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 - 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 - 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 - 95
percent
When must TCEQ be notified about expansions of a treatment facility? - Before
construction
In an anaerobic digester, the percentage of methane and carbon dioxide gas content
should be - 70% methane, 30% carbon dioxide
The temperature of an anaerobic digester should be maintained at a minimum of -
95° F
What type of wastewater treatment operates in the endogenous bacteria growth
phase? - Extended air
Why is recirculation needed in a trickling filter? - 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? - Class A Class C (a and d)
Disinfection with chlorine is the most effective at a pH of - 6.0
, The biomass on a normal functioning RBC has what appearance? - Grey to brown and
0.05 to 0.1 inch thick
The sludge from a primary clarifier should percent solids? - 4% to 6%
What is eutrophication in a pond system? - Enrichment with nitrogen and
phosphorous Causes algae blooms (b and c)
How often should pH meters be calibrated? - Daily
In Texas, pH meters are required to be calibrated on how many buffers? - 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 - 2941
The parameters of the BOD test are - 5 days at 20° Centigrade
Standard Dimension Ratio in pvc pipe is defined as - Ratio of OD pipe diameter to
wall thickness
How should shoring be removed from a trench? - 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 - part of the collection system and the responsibility of the
utility
Effective communication depends on - being a good listener
When designing a wastewater collection system, the engineer considers the
population for how many years in the future? - 50
According to 30 TAC Chapter 317, all pipe and fittings used in wastewater pressure
shall have a minimum psi pressure rating of - 150
The minimum velocity of flow in a wastewater line should be - 2.0 fps
At a construction job site, as the roadway speed increases, the spacing between
cones and barricades should - increase
The major cause of wastewater line stoppages is - roots and grease
Carbon monoxide (CO) poisoning symptoms are - 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 - 1
inch
