TCEQ Wastewater (Class D) License TEST
STUDY GUIDE 2026/2027 COMPLETE
QUESTIONS WITH CORRECT DETAILED
ANSWERS || 100% GUARANTEED PASS
<RECENT VERSION>
1. Hydrologic Cycle - ANSWER The natural exchange of water between the
earth and the air.
2. Evaporation - ANSWER Causes surface water to enter the atmosphere and
begin the Hydrologic Cycle.
3. Precipitation - ANSWER Rain or snow falling from clouds.
4. Condensation - ANSWER What causes water vapor to form clouds.
5. Groundwater sources - ANSWER Generally better protected from
contamination than surface water sources.
6. Wastewater systems - ANSWER The goal is to properly collect, transport,
and treat both domestic and industrial wastewater prior to discharge into the
environment.
7. Hydraulic Loading - ANSWER Hydraulic loading and organic loading are
two criteria used to control trickling filter operations.
,8. Fixed-Film Treatment Processes - ANSWER Trickling filters in their
various forms are classified as fixed-film treatment processes.
9. Soluble BOD - ANSWER The BOD in a waste stream that remains
following filtration through a standard glass filter.
10.Aerobic Microbial Population - ANSWER The aerobic microbial population
consists of bacteria, protozoa, algae, fungi and worms growing on the media.
11.Foul Odors - ANSWER Foul odors coming from a trickling filter is usually
the result of inadequate ventilation or lack of dissolved oxygen in the
wastewater.
12.COD - ANSWER COD is a better indicator to use than BOD when quick
results of organic loading is required.
13.Air Drive Unit - ANSWER A method of causing the shaft of a RBC to rotate
by using air that is bubbled through the reaction tank.
14.Mechanical Drive Unit - ANSWER A traditional drive unit that uses an
electric motor, drive-chain and sprockets to rotate the shaft on a RBC.
15.Fixed Film Process - ANSWER A type of waste treatment process that
utilizes a biomass that is attached to a medium and is therefore said to be
fixed.
16.RBC Media - ANSWER The RBC discs are typically made from high
density polyethylene (HDPE) with standard disc assemblies having about
100,000 ft2 of surface area for microorganisms to attach and grow.
,17.Preliminary and Primary Treatment - ANSWER The RBC process requires
effective preliminary and primary treatment for it to operate properly.
18.RBC disc design - ANSWER The normal RBC disc design has about
100,000 square feet of surface area when all the discs attached to a single
shaft are combined.
19.RBC disc submersion - ANSWER The discs on an RBC can be submerged
in the wastewater to a level that covers as much as 40% of the disc surface
area.
20.Healthy biomass thickness - ANSWER A healthy biomass on the discs in
the first stage of the process should be between one-sixteenth and one-eighth
of an inch thick with a light brown color.
21.Hydraulic contact time - ANSWER Each stage of the RBC process should
have sufficient volume to provide for a hydraulic contact time of about 1
hour.
22.Minimum velocity required to keep solids in suspension? - ANSWER
2ft/sec
23.Minimum required velocity a inverted siphon requires? - ANSWER 3ft/sec
24.A common chemical used for disinfecting a small public water supply is:
a) soda ash
b) copper sulfate
c) sodium hypochlorite
d) fluoride
, e) sodium chloride - ANSWER c) sodium hypochlorite
25.Gravity filters will remove which of the following from surface water
supplies:
a) turbidity
b) taste and odors
c) nitrates
d) hardness
e) chlorides - ANSWER a) turbidity
26.If you added 3.5 mg/L of chlorine to your storage tank and 30 minutes later
measured the residual at 1.2 mg/L, what was the chlorine demand in the
tank?
a) 4.2
b) 2.9
c) 0.3
d) 2.3
e) 4.7 - ANSWER d) 2.3
27.Your ground storage tank is 15 feet high and 30 feet in diameter. About how
much water can it hold?
a) 31,700 gallons
b) 79,270 gallons
c) 50, 490 gallons
d) 25,150 gallons
e) 10,600 gallons - ANSWER ...
28.When fecal coliform organisms are found in a water supply, it is an
indication that:
a) the water supply is contaminated
b) pathogenic organisms might be present
c) the water may be unsuitable for drinking
d) follow-up sampling must take place
STUDY GUIDE 2026/2027 COMPLETE
QUESTIONS WITH CORRECT DETAILED
ANSWERS || 100% GUARANTEED PASS
<RECENT VERSION>
1. Hydrologic Cycle - ANSWER The natural exchange of water between the
earth and the air.
2. Evaporation - ANSWER Causes surface water to enter the atmosphere and
begin the Hydrologic Cycle.
3. Precipitation - ANSWER Rain or snow falling from clouds.
4. Condensation - ANSWER What causes water vapor to form clouds.
5. Groundwater sources - ANSWER Generally better protected from
contamination than surface water sources.
6. Wastewater systems - ANSWER The goal is to properly collect, transport,
and treat both domestic and industrial wastewater prior to discharge into the
environment.
7. Hydraulic Loading - ANSWER Hydraulic loading and organic loading are
two criteria used to control trickling filter operations.
,8. Fixed-Film Treatment Processes - ANSWER Trickling filters in their
various forms are classified as fixed-film treatment processes.
9. Soluble BOD - ANSWER The BOD in a waste stream that remains
following filtration through a standard glass filter.
10.Aerobic Microbial Population - ANSWER The aerobic microbial population
consists of bacteria, protozoa, algae, fungi and worms growing on the media.
11.Foul Odors - ANSWER Foul odors coming from a trickling filter is usually
the result of inadequate ventilation or lack of dissolved oxygen in the
wastewater.
12.COD - ANSWER COD is a better indicator to use than BOD when quick
results of organic loading is required.
13.Air Drive Unit - ANSWER A method of causing the shaft of a RBC to rotate
by using air that is bubbled through the reaction tank.
14.Mechanical Drive Unit - ANSWER A traditional drive unit that uses an
electric motor, drive-chain and sprockets to rotate the shaft on a RBC.
15.Fixed Film Process - ANSWER A type of waste treatment process that
utilizes a biomass that is attached to a medium and is therefore said to be
fixed.
16.RBC Media - ANSWER The RBC discs are typically made from high
density polyethylene (HDPE) with standard disc assemblies having about
100,000 ft2 of surface area for microorganisms to attach and grow.
,17.Preliminary and Primary Treatment - ANSWER The RBC process requires
effective preliminary and primary treatment for it to operate properly.
18.RBC disc design - ANSWER The normal RBC disc design has about
100,000 square feet of surface area when all the discs attached to a single
shaft are combined.
19.RBC disc submersion - ANSWER The discs on an RBC can be submerged
in the wastewater to a level that covers as much as 40% of the disc surface
area.
20.Healthy biomass thickness - ANSWER A healthy biomass on the discs in
the first stage of the process should be between one-sixteenth and one-eighth
of an inch thick with a light brown color.
21.Hydraulic contact time - ANSWER Each stage of the RBC process should
have sufficient volume to provide for a hydraulic contact time of about 1
hour.
22.Minimum velocity required to keep solids in suspension? - ANSWER
2ft/sec
23.Minimum required velocity a inverted siphon requires? - ANSWER 3ft/sec
24.A common chemical used for disinfecting a small public water supply is:
a) soda ash
b) copper sulfate
c) sodium hypochlorite
d) fluoride
, e) sodium chloride - ANSWER c) sodium hypochlorite
25.Gravity filters will remove which of the following from surface water
supplies:
a) turbidity
b) taste and odors
c) nitrates
d) hardness
e) chlorides - ANSWER a) turbidity
26.If you added 3.5 mg/L of chlorine to your storage tank and 30 minutes later
measured the residual at 1.2 mg/L, what was the chlorine demand in the
tank?
a) 4.2
b) 2.9
c) 0.3
d) 2.3
e) 4.7 - ANSWER d) 2.3
27.Your ground storage tank is 15 feet high and 30 feet in diameter. About how
much water can it hold?
a) 31,700 gallons
b) 79,270 gallons
c) 50, 490 gallons
d) 25,150 gallons
e) 10,600 gallons - ANSWER ...
28.When fecal coliform organisms are found in a water supply, it is an
indication that:
a) the water supply is contaminated
b) pathogenic organisms might be present
c) the water may be unsuitable for drinking
d) follow-up sampling must take place
