Texas Wastewater A | QUESTIONS AND ANSWERS |
2025/2026
What is TCEQ doing to control "point source" pollution of *Permitting of domestic wastewater plants
the Texas waterways? *Permitting of industrial wastewater plants
Describe proper design of force main wastewater lines. Minimum two fps velocity with the smallest pump operating alone. Minimum four
inch diameter pipe with 150 psi rating.
What is Standard Dimension Ratio? Ratio of outside pipe diameter (OD) to wall thickness (PVC)
Describe proper design of gravity wastewater lines. 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? 24 inches and be at least 4 feet wide.
pH meters should be calibrated how often? Daily with at least two buffers.
What standards should be used for calibration
purposes?
What is the standard chlorine residual and minimum a. 1.0 mg/L for a minimum 20 minutes detention time at peak flow b. No chlorine
contact time on Texas wastewater permits? residual needed if detention time is greater than 21 days
As the complexity of an organization increases, what Planning
management function becomes most important?
What is the effective chlorine disinfecting agent? Hypochlorous Acid (HOCl)
Does pH affect the chlorination process? Explain your When using free chlorine the disinfectant is HOCl acid. As such it is much more
answer. 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 Texas standard is 1.0 mg/L for a minimum 20 minutes detention time at peak flow.
standard on permits and the minimum detention time? Maximum residual allowed is 4.0 mg/L.
What is the maximum residual allowed?
A treatment plant has a clarifier that is 60 feet in diameter Formula
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?
What activated process cannot nitrify in a single stage? Contact Stabilization
What is the GPM output of a piston pump with an 8-inch Formula
diameter piston with a 10-inch stroke operating at 50
strokes per minute?
A treatment plant has a clarifier that is 60 feet in diameter Formulas
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?
A primary clarifier has a flow of 3.0 MGD and has a Formulas
diameter of 100 feet. It is 12 feet deep and has 24 inches of
freeboard. What is the detention time in hours?
Anaerobic digester gas should contain? 65-75% methane, 25-35% carbon dioxide and 1-5% nitrogen.
An activated sludge plant has an average daily flow of Formulas MCRT
3.5 MG. The aeration tank capacity is 1.2 MG with a MLSS
concentration of 3200 mg/L. The clarifier has a
capacity of 400,000 gallons with a MLSS concentration
of 6,000 mg/L. The wasting rate is 40,000 gallons per
day with a MLSS concentration of 8, 000 mg/L. The
effluent TSS is 18 mg/L. Assuming volatile concentrations
of 70%, what is the MCRT and what type of activated
sludge plant should this be?
What are some of the causes of filaments in the aeration a.low DO
basin? b. low organic loading
c. septic wastes
d.nutrient deficiencies .
e.high sulfur content
Good sludge quality will have a predominance of what Ciliated protozoa
organisms in the MLSS?
When an RBC is operating correctly, how will the slime Grey to brown 0.05 to 0.1 inches thick
appear on the media?
2025/2026
What is TCEQ doing to control "point source" pollution of *Permitting of domestic wastewater plants
the Texas waterways? *Permitting of industrial wastewater plants
Describe proper design of force main wastewater lines. Minimum two fps velocity with the smallest pump operating alone. Minimum four
inch diameter pipe with 150 psi rating.
What is Standard Dimension Ratio? Ratio of outside pipe diameter (OD) to wall thickness (PVC)
Describe proper design of gravity wastewater lines. 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? 24 inches and be at least 4 feet wide.
pH meters should be calibrated how often? Daily with at least two buffers.
What standards should be used for calibration
purposes?
What is the standard chlorine residual and minimum a. 1.0 mg/L for a minimum 20 minutes detention time at peak flow b. No chlorine
contact time on Texas wastewater permits? residual needed if detention time is greater than 21 days
As the complexity of an organization increases, what Planning
management function becomes most important?
What is the effective chlorine disinfecting agent? Hypochlorous Acid (HOCl)
Does pH affect the chlorination process? Explain your When using free chlorine the disinfectant is HOCl acid. As such it is much more
answer. 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 Texas standard is 1.0 mg/L for a minimum 20 minutes detention time at peak flow.
standard on permits and the minimum detention time? Maximum residual allowed is 4.0 mg/L.
What is the maximum residual allowed?
A treatment plant has a clarifier that is 60 feet in diameter Formula
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?
What activated process cannot nitrify in a single stage? Contact Stabilization
What is the GPM output of a piston pump with an 8-inch Formula
diameter piston with a 10-inch stroke operating at 50
strokes per minute?
A treatment plant has a clarifier that is 60 feet in diameter Formulas
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?
A primary clarifier has a flow of 3.0 MGD and has a Formulas
diameter of 100 feet. It is 12 feet deep and has 24 inches of
freeboard. What is the detention time in hours?
Anaerobic digester gas should contain? 65-75% methane, 25-35% carbon dioxide and 1-5% nitrogen.
An activated sludge plant has an average daily flow of Formulas MCRT
3.5 MG. The aeration tank capacity is 1.2 MG with a MLSS
concentration of 3200 mg/L. The clarifier has a
capacity of 400,000 gallons with a MLSS concentration
of 6,000 mg/L. The wasting rate is 40,000 gallons per
day with a MLSS concentration of 8, 000 mg/L. The
effluent TSS is 18 mg/L. Assuming volatile concentrations
of 70%, what is the MCRT and what type of activated
sludge plant should this be?
What are some of the causes of filaments in the aeration a.low DO
basin? b. low organic loading
c. septic wastes
d.nutrient deficiencies .
e.high sulfur content
Good sludge quality will have a predominance of what Ciliated protozoa
organisms in the MLSS?
When an RBC is operating correctly, how will the slime Grey to brown 0.05 to 0.1 inches thick
appear on the media?
