Texas Wastewater A UPDATED Exam
Questions and CORRECT Answers
What is TCEQ doing to control "point source" pollution of the Texas waterways? - CORRECT
ANSWER *Permitting of domestic wastewater plants
*Permitting of industrial wastewater plants
Describe proper design of force main wastewater lines. - CORRECT ANSWER Minimum
two fps velocity with the smallest pump operating alone. Minimum four inch diameter pipe with
150 psi rating.
What is Standard Dimension Ratio? - CORRECT ANSWER Ratio of outside pipe
diameter (OD) to wall thickness (PVC)
Describe proper design of gravity wastewater lines. - CORRECT ANSWER Designed to
flow half full ,under normal conditions, at a minimum of two fps and a maximum of ten fps.
Manholes should have a minimum opening of? - CORRECT ANSWER 24 inches and be
at least 4 feet wide.
pH meters should be calibrated how often? What standards should be used for calibration
purposes? - CORRECT ANSWER Daily with at least two buffers.
What is the standard chlorine residual and minimum contact time on Texas wastewater permits?
- CORRECT ANSWER a. 1.0 mg/L for a minimum 20 minutes detention time at peak
flow b. No chlorine residual needed if detention time is greater than 21 days
As the complexity of an organization increases, what management function becomes most
important? - CORRECT ANSWER Planning
, What is the effective chlorine disinfecting agent? - CORRECT ANSWER Hypochlorous
Acid (HOCl)
Does pH affect the chlorination process? Explain your answer. - CORRECT
ANSWER When using free chlorine the disinfectant is HOCl acid. As such it is much
more effective at pH's below 7.0. Above 7.0 pH the acid begins to be neutralized.
What is the effluent chlorine residual in Texas that is standard on permits and the minimum
detention time? What is the maximum residual allowed? - CORRECT ANSWER Texas
standard is 1.0 mg/L for a minimum 20 minutes detention time at peak flow. Maximum residual
allowed is 4.0 mg/L.
A treatment plant has a clarifier that is 60 feet in diameter and is 10 feet deep. The weir is 2 feet
inside the outer clarifier wall. The flow is 1.0 MGD. The weir and outflow channel is 3 feet deep.
a. What is the detention time in hours? - CORRECT ANSWER Formula
What activated process cannot nitrify in a single stage? - CORRECT ANSWER Contact
Stabilization
What is the GPM output of a piston pump with an 8-inch diameter piston with a 10-inch stroke
operating at 50 strokes per minute? - CORRECT ANSWER Formula
A treatment plant has a clarifier that is 60 feet in diameter and is 10 feet deep. The weir is 2 feet
inside the outer clarifier wall. The flow is 1.0 MGD. The weir and outflow channel is 3 feet deep.
a. What is the detention time in hours?
b. What is the surface loading in gal/ft2/day?
c. What is the weir loading in gal/linear ft/day? - CORRECT ANSWER Formulas
A primary clarifier has a flow of 3.0 MGD and has a diameter of 100 feet. It is 12 feet deep and
has 24 inches of freeboard. What is the detention time in hours? - CORRECT
ANSWER Formulas
Questions and CORRECT Answers
What is TCEQ doing to control "point source" pollution of the Texas waterways? - CORRECT
ANSWER *Permitting of domestic wastewater plants
*Permitting of industrial wastewater plants
Describe proper design of force main wastewater lines. - CORRECT ANSWER Minimum
two fps velocity with the smallest pump operating alone. Minimum four inch diameter pipe with
150 psi rating.
What is Standard Dimension Ratio? - CORRECT ANSWER Ratio of outside pipe
diameter (OD) to wall thickness (PVC)
Describe proper design of gravity wastewater lines. - CORRECT ANSWER Designed to
flow half full ,under normal conditions, at a minimum of two fps and a maximum of ten fps.
Manholes should have a minimum opening of? - CORRECT ANSWER 24 inches and be
at least 4 feet wide.
pH meters should be calibrated how often? What standards should be used for calibration
purposes? - CORRECT ANSWER Daily with at least two buffers.
What is the standard chlorine residual and minimum contact time on Texas wastewater permits?
- CORRECT ANSWER a. 1.0 mg/L for a minimum 20 minutes detention time at peak
flow b. No chlorine residual needed if detention time is greater than 21 days
As the complexity of an organization increases, what management function becomes most
important? - CORRECT ANSWER Planning
, What is the effective chlorine disinfecting agent? - CORRECT ANSWER Hypochlorous
Acid (HOCl)
Does pH affect the chlorination process? Explain your answer. - CORRECT
ANSWER When using free chlorine the disinfectant is HOCl acid. As such it is much
more effective at pH's below 7.0. Above 7.0 pH the acid begins to be neutralized.
What is the effluent chlorine residual in Texas that is standard on permits and the minimum
detention time? What is the maximum residual allowed? - CORRECT ANSWER Texas
standard is 1.0 mg/L for a minimum 20 minutes detention time at peak flow. Maximum residual
allowed is 4.0 mg/L.
A treatment plant has a clarifier that is 60 feet in diameter and is 10 feet deep. The weir is 2 feet
inside the outer clarifier wall. The flow is 1.0 MGD. The weir and outflow channel is 3 feet deep.
a. What is the detention time in hours? - CORRECT ANSWER Formula
What activated process cannot nitrify in a single stage? - CORRECT ANSWER Contact
Stabilization
What is the GPM output of a piston pump with an 8-inch diameter piston with a 10-inch stroke
operating at 50 strokes per minute? - CORRECT ANSWER Formula
A treatment plant has a clarifier that is 60 feet in diameter and is 10 feet deep. The weir is 2 feet
inside the outer clarifier wall. The flow is 1.0 MGD. The weir and outflow channel is 3 feet deep.
a. What is the detention time in hours?
b. What is the surface loading in gal/ft2/day?
c. What is the weir loading in gal/linear ft/day? - CORRECT ANSWER Formulas
A primary clarifier has a flow of 3.0 MGD and has a diameter of 100 feet. It is 12 feet deep and
has 24 inches of freeboard. What is the detention time in hours? - CORRECT
ANSWER Formulas
