TCEQ Wastewater License Exam
What are the steps of the Water Use Cycle? - correct answer Environment --> Water Treatment
--> Water Distribution System --> Customer Use --> Wastewater Collection System -->
Wastewater Treatment --> Environment
What are the benefits of the collection system? - correct answer - Removal of health hazards
- Prevention of odors and flies
- Cleanliness and appearance
- Comfort and convenience
Septic vs. Fresh wastewater? - correct answer Septic wastewater doesn't contain dissolved
oxygen and is difficult to treat. Fresh wastewater contains dissolved oxygen and is easier to
treat, which results in higher quality effluent
Inflow - correct answer Surface runoff that enters the collection system
Infiltration - correct answer Groundwater that enters the collection system through holes,
cracks, etc.
What is the average domestic contribution to the collection system? (Per person/day) - correct
answer 100 gallons per day
What are the four wastewater characteristics? - correct answer Physical, Chemical,
Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids - correct answer 99.9% water, 0.1% solids
Settleable solids - correct answer Suspended solids that will settle when wastewater flow is still
or slow moving
, TCEQ Wastewater License Exam
What is the pH scale range? - correct answer 0 (most acidic) to 14 (most basic), 7 is neutral
Does septic or freshwater have a lower pH? Why? - correct answer Septic has lower pH due to
volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? - correct answer A colorless, toxic, and
flammable gas that resembles the smell of rotten eggs. It results from the bacterial breakdown
of organic matter in the absence of oxygen. It is heavier than air.
What is Methane? (CH4) What percentage of methane is in digester gas? - correct answer A
colorless, odorless, and highly flammable gas. Methane is an asphyxiant and is lighter than air.
Digester gas contains 65% methane and is used for heating fuel or operating equipment.
What is carbon dioxide? (CO2) - correct answer A colorless, odorless gas that has a suffocating
effect. When inhaled at 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) - correct answer A colorless, odorless, and tasteless gas
Why is oil and grease a concern if present in wastewater? - correct answer It may cause
explosions, fires, line blockages, and odor
What are chlorides and why are excessive chlorides in wastewater bad? - correct answer
Excessive chlorides interfere with treatment processes, especially trickling filters. They also
affect laboratory tests.
What does the BOD test measure? - correct answer It measures wastewater strength and the
oxygen depleting effect of wastewater effluent on the receiving stream. Specifically, it indicates
What are the steps of the Water Use Cycle? - correct answer Environment --> Water Treatment
--> Water Distribution System --> Customer Use --> Wastewater Collection System -->
Wastewater Treatment --> Environment
What are the benefits of the collection system? - correct answer - Removal of health hazards
- Prevention of odors and flies
- Cleanliness and appearance
- Comfort and convenience
Septic vs. Fresh wastewater? - correct answer Septic wastewater doesn't contain dissolved
oxygen and is difficult to treat. Fresh wastewater contains dissolved oxygen and is easier to
treat, which results in higher quality effluent
Inflow - correct answer Surface runoff that enters the collection system
Infiltration - correct answer Groundwater that enters the collection system through holes,
cracks, etc.
What is the average domestic contribution to the collection system? (Per person/day) - correct
answer 100 gallons per day
What are the four wastewater characteristics? - correct answer Physical, Chemical,
Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids - correct answer 99.9% water, 0.1% solids
Settleable solids - correct answer Suspended solids that will settle when wastewater flow is still
or slow moving
, TCEQ Wastewater License Exam
What is the pH scale range? - correct answer 0 (most acidic) to 14 (most basic), 7 is neutral
Does septic or freshwater have a lower pH? Why? - correct answer Septic has lower pH due to
volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? - correct answer A colorless, toxic, and
flammable gas that resembles the smell of rotten eggs. It results from the bacterial breakdown
of organic matter in the absence of oxygen. It is heavier than air.
What is Methane? (CH4) What percentage of methane is in digester gas? - correct answer A
colorless, odorless, and highly flammable gas. Methane is an asphyxiant and is lighter than air.
Digester gas contains 65% methane and is used for heating fuel or operating equipment.
What is carbon dioxide? (CO2) - correct answer A colorless, odorless gas that has a suffocating
effect. When inhaled at 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) - correct answer A colorless, odorless, and tasteless gas
Why is oil and grease a concern if present in wastewater? - correct answer It may cause
explosions, fires, line blockages, and odor
What are chlorides and why are excessive chlorides in wastewater bad? - correct answer
Excessive chlorides interfere with treatment processes, especially trickling filters. They also
affect laboratory tests.
What does the BOD test measure? - correct answer It measures wastewater strength and the
oxygen depleting effect of wastewater effluent on the receiving stream. Specifically, it indicates
