Texas Wastewater Class A Complete
Exam Answers With Detailed
Solutions
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
15,000 gallons of sludge with 4% solids is run through a press to produce a 25% cake.
How many dry metric tons of sludge will be disposed of? [Assume a conversion factor of
2200 Ibs per dry metric tons.] - CORRECT ANSWER-2.27
,Under the Texas Hazard Communication Act employers must annually report chemicals
stored above what limits? - CORRECT ANSWER-55 gals/500 Ibs
Under EPA regulations utilities that store chlorine gas over what quantity are required to
have a "Risk Management Plan"? 2500 Ibs - CORRECT ANSWER-2500 Ibs
The normal appearance of the biomass on an RBC is - CORRECT ANSWER-grey to
brown and .05 to.1 inch thick shaggy and stringy appearance
Wastewater What are the effects of organic pollution on the receiving stream? -
CORRECT ANSWER-Decomposition of organics lowers DO levels adversely affecting
aquatic life Nutrients encourage the growth of aquatic organism such as algae c. Lower
water quality downstream is more difficult treat for potable use d. All of the above
A 30 ml wastewater sample, is incubated 5 days at 20 degrees C. The DO before was
6.0 mg/L and the DO after was 3.5 mg/L. What is the reportable BOD? - CORRECT
ANSWER-(6-3.5) x 300 30 b. 25
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
Exam Answers With Detailed
Solutions
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
15,000 gallons of sludge with 4% solids is run through a press to produce a 25% cake.
How many dry metric tons of sludge will be disposed of? [Assume a conversion factor of
2200 Ibs per dry metric tons.] - CORRECT ANSWER-2.27
,Under the Texas Hazard Communication Act employers must annually report chemicals
stored above what limits? - CORRECT ANSWER-55 gals/500 Ibs
Under EPA regulations utilities that store chlorine gas over what quantity are required to
have a "Risk Management Plan"? 2500 Ibs - CORRECT ANSWER-2500 Ibs
The normal appearance of the biomass on an RBC is - CORRECT ANSWER-grey to
brown and .05 to.1 inch thick shaggy and stringy appearance
Wastewater What are the effects of organic pollution on the receiving stream? -
CORRECT ANSWER-Decomposition of organics lowers DO levels adversely affecting
aquatic life Nutrients encourage the growth of aquatic organism such as algae c. Lower
water quality downstream is more difficult treat for potable use d. All of the above
A 30 ml wastewater sample, is incubated 5 days at 20 degrees C. The DO before was
6.0 mg/L and the DO after was 3.5 mg/L. What is the reportable BOD? - CORRECT
ANSWER-(6-3.5) x 300 30 b. 25
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
