TCEQ Wastewater License Exam Questions And
100% Correct Answers
What is the sequence of steps in the Water Use Cycle? - ANSWER Environment --> Water
Treatment --> Water Distribution System --> Customer Use --> Wastewater Collection
System --> Wastewater Treatment --> Environment
What are the benefits to the collection system? - ANSWER - Control of health nuisances
- Eliminating odors and flies
- Cleanliness and aesthetics
- Comfort and convenience
Septic vs. Fresh wastewater? - ANSWER Septic wastewater doesn't contain dissolved
oxygen and is hard to treat. Fresh wastewater does contain dissolved oxygen and is
easier to treat, yielding higher quality effluent
Inflow - ANSWER Surface runoff that enters the collection system
Infiltration - ANSWER Groundwater that enters the collection system through holes,
cracks, etc.
What is the average domestic contribution to the collection system? Per person/day -
ANSWER 100 gallons per day
What are the four wastewater characteristics? - ANSWER Physical, Chemical,
Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids - ANSWER 99.9% water, 0.1% solids
, Settleable solids - ANSWER Suspended solids that will settle when wastewater flow is
still or slow moving
What is the range of the pH scale? -ANSWER 0 (most acidic) to 14 (most basic), 7 is
neutral
Which of the following has the lower pH, septic or freshwater? Why? -ANSWER Septic
has lower pH because of volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? - ANSWER Colorless, toxic,
flammable gas with the characteristic odour of rotten eggs. It is produced by the
bacterial decomposition of organic material in the absence of oxygen. It is heavier than
air.
What is Methane? (CH4) What percentage of methane is in digester gas? - ANSWER A
colorless, odorless and highly flammable gas. Methane is an asphyxiant and lighter than
air. Digester gas contains 65% methane and is used for heating fuel or operating
equipment.
What is carbon dioxide? (CO2) - ANSWER A colorless and odorless gas that has a
smothering effect. When inhaled in higher than normal concentrations, it can produce a
sour taste in the mouth and a stinging sensation in the nose and throat.
What is carbon monoxide? (CO) - ANSWER A colorless, odorless, and tasteless gas
Why is oil and grease a concern if present in wastewater? - ANSWER It can cause
explosions, fires, line blockages, and odor
What are chlorides and why is excessive chlorides in wastewater bad? - ANSWER
Excessive chlorides interfere with treatment processes, especially trickling filters. They
also can interfere with laboratory tests.
100% Correct Answers
What is the sequence of steps in the Water Use Cycle? - ANSWER Environment --> Water
Treatment --> Water Distribution System --> Customer Use --> Wastewater Collection
System --> Wastewater Treatment --> Environment
What are the benefits to the collection system? - ANSWER - Control of health nuisances
- Eliminating odors and flies
- Cleanliness and aesthetics
- Comfort and convenience
Septic vs. Fresh wastewater? - ANSWER Septic wastewater doesn't contain dissolved
oxygen and is hard to treat. Fresh wastewater does contain dissolved oxygen and is
easier to treat, yielding higher quality effluent
Inflow - ANSWER Surface runoff that enters the collection system
Infiltration - ANSWER Groundwater that enters the collection system through holes,
cracks, etc.
What is the average domestic contribution to the collection system? Per person/day -
ANSWER 100 gallons per day
What are the four wastewater characteristics? - ANSWER Physical, Chemical,
Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids - ANSWER 99.9% water, 0.1% solids
, Settleable solids - ANSWER Suspended solids that will settle when wastewater flow is
still or slow moving
What is the range of the pH scale? -ANSWER 0 (most acidic) to 14 (most basic), 7 is
neutral
Which of the following has the lower pH, septic or freshwater? Why? -ANSWER Septic
has lower pH because of volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? - ANSWER Colorless, toxic,
flammable gas with the characteristic odour of rotten eggs. It is produced by the
bacterial decomposition of organic material in the absence of oxygen. It is heavier than
air.
What is Methane? (CH4) What percentage of methane is in digester gas? - ANSWER A
colorless, odorless and highly flammable gas. Methane is an asphyxiant and lighter than
air. Digester gas contains 65% methane and is used for heating fuel or operating
equipment.
What is carbon dioxide? (CO2) - ANSWER A colorless and odorless gas that has a
smothering effect. When inhaled in higher than normal concentrations, it can produce a
sour taste in the mouth and a stinging sensation in the nose and throat.
What is carbon monoxide? (CO) - ANSWER A colorless, odorless, and tasteless gas
Why is oil and grease a concern if present in wastewater? - ANSWER It can cause
explosions, fires, line blockages, and odor
What are chlorides and why is excessive chlorides in wastewater bad? - ANSWER
Excessive chlorides interfere with treatment processes, especially trickling filters. They
also can interfere with laboratory tests.
