Texas Wastewater A
*Permitting of domestic wastewater plants
*Permitting of industrial wastewater plants - answers✔✔What is TCEQ doing to control "point source"
pollution of the Texas waterways?
Minimum two fps velocity with the smallest pump operating alone. Minimum four inch diameter pipe
with 150 psi rating. - answers✔✔Describe proper design of force main wastewater lines.
Ratio of outside pipe diameter (OD) to wall thickness (PVC) - answers✔✔What is Standard Dimension
Ratio?
Designed to flow half full ,under normal conditions, at a minimum of two fps and a maximum of ten fps.
- answers✔✔Describe proper design of gravity wastewater lines.
24 inches and be at least 4 feet wide. - answers✔✔Manholes should have a minimum opening of?
Daily with at least two buffers. - answers✔✔pH meters should be calibrated how often? What standards
should be used for calibration purposes?
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 - answers✔✔What is the standard chlorine residual and
minimum contact time on Texas wastewater permits?
Planning - answers✔✔As the complexity of an organization increases, what management function
becomes most important?
Hypochlorous Acid (HOCl) - answers✔✔What is the effective chlorine disinfecting agent?
, 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. - answers✔✔Does pH affect the chlorination
process? Explain your 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. - answers✔✔What is the effluent chlorine residual in Texas that is standard on
permits and the minimum detention time? What is the maximum residual allowed?
Formula - answers✔✔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?
Contact Stabilization - answers✔✔What activated process cannot nitrify in a single stage?
Formula - answers✔✔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?
Formulas - answers✔✔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?
Formulas - answers✔✔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?
65-75% methane, 25-35% carbon dioxide and 1-5% nitrogen. - answers✔✔Anaerobic digester gas
should contain?
Formulas MCRT - answers✔✔An activated sludge plant has an average daily flow of 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
*Permitting of domestic wastewater plants
*Permitting of industrial wastewater plants - answers✔✔What is TCEQ doing to control "point source"
pollution of the Texas waterways?
Minimum two fps velocity with the smallest pump operating alone. Minimum four inch diameter pipe
with 150 psi rating. - answers✔✔Describe proper design of force main wastewater lines.
Ratio of outside pipe diameter (OD) to wall thickness (PVC) - answers✔✔What is Standard Dimension
Ratio?
Designed to flow half full ,under normal conditions, at a minimum of two fps and a maximum of ten fps.
- answers✔✔Describe proper design of gravity wastewater lines.
24 inches and be at least 4 feet wide. - answers✔✔Manholes should have a minimum opening of?
Daily with at least two buffers. - answers✔✔pH meters should be calibrated how often? What standards
should be used for calibration purposes?
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 - answers✔✔What is the standard chlorine residual and
minimum contact time on Texas wastewater permits?
Planning - answers✔✔As the complexity of an organization increases, what management function
becomes most important?
Hypochlorous Acid (HOCl) - answers✔✔What is the effective chlorine disinfecting agent?
, 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. - answers✔✔Does pH affect the chlorination
process? Explain your 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. - answers✔✔What is the effluent chlorine residual in Texas that is standard on
permits and the minimum detention time? What is the maximum residual allowed?
Formula - answers✔✔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?
Contact Stabilization - answers✔✔What activated process cannot nitrify in a single stage?
Formula - answers✔✔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?
Formulas - answers✔✔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?
Formulas - answers✔✔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?
65-75% methane, 25-35% carbon dioxide and 1-5% nitrogen. - answers✔✔Anaerobic digester gas
should contain?
Formulas MCRT - answers✔✔An activated sludge plant has an average daily flow of 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
