TCEQ Wastewater License
Exam Study Guide & Practice
Questions 2026/2027
, What are the steps of the Water Use Cycle? Environment --> Water Treatment --> Water Distribution System --> Customer Use -
-> Wastewater Collection System --> Wastewater Treatment --> Environment
What are the benefits of the collection system? - Removal of health hazards
- Prevention of odors and flies
- Cleanliness and appearance
- Comfort and convenience
Septic vs. Fresh wastewater? 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 Surface runoff that enters the collection system
Infiltration Groundwater that enters the collection system through holes, cracks, etc.
What is the average domestic contribution to the collection 100 gallons per day
system? (Per person/day)
What are the four wastewater characteristics? Physical, Chemical, Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids 99.9% water, 0.1% solids
Settleable solids Suspended solids that will settle when wastewater flow is still or slow moving
What is the pH scale range? 0 (most acidic) to 14 (most basic), 7 is neutral
Does septic or freshwater have a lower pH? Why? Septic has lower pH due to volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? 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 A colorless, odorless, and highly flammable gas. Methane is an asphyxiant and is
in digester gas? lighter than air. Digester gas contains 65% methane and is used for heating fuel or
operating equipment.
What is carbon dioxide? (CO2) 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) A colorless, odorless, and tasteless gas
Exam Study Guide & Practice
Questions 2026/2027
, What are the steps of the Water Use Cycle? Environment --> Water Treatment --> Water Distribution System --> Customer Use -
-> Wastewater Collection System --> Wastewater Treatment --> Environment
What are the benefits of the collection system? - Removal of health hazards
- Prevention of odors and flies
- Cleanliness and appearance
- Comfort and convenience
Septic vs. Fresh wastewater? 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 Surface runoff that enters the collection system
Infiltration Groundwater that enters the collection system through holes, cracks, etc.
What is the average domestic contribution to the collection 100 gallons per day
system? (Per person/day)
What are the four wastewater characteristics? Physical, Chemical, Bacteriological, and Radiological
Domestic wastewater is ___% water and ___% solids 99.9% water, 0.1% solids
Settleable solids Suspended solids that will settle when wastewater flow is still or slow moving
What is the pH scale range? 0 (most acidic) to 14 (most basic), 7 is neutral
Does septic or freshwater have a lower pH? Why? Septic has lower pH due to volatile acids formed from wastewater decomposition
What is Hydrogen Sulfide (H2S)? When does it occur? 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 A colorless, odorless, and highly flammable gas. Methane is an asphyxiant and is
in digester gas? lighter than air. Digester gas contains 65% methane and is used for heating fuel or
operating equipment.
What is carbon dioxide? (CO2) 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) A colorless, odorless, and tasteless gas
