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OSSF INSTALLER 2 Exam (updated 2026) Questions &
Answers | Latest Already Graded A+ UPDATE |2026
Which of the following is true of aerobic treatment plants ?
a . Able to maintain a minimum DO of 4.0 mg / L
b . Odor free , utilize aerobic bacteria and produce hydrogen sulfide gas
.
c. Use aerobic bacteria and oxygen to breakdown complex organics and
produce carbon dioxide
d . Use aerobic bacteria and carbon dioxide to produce complex organic
compounds and natural gas ......ANSWER......c . Use aerobic bacteria and
oxygen to breakdown complex organics and produce carbon dioxide
To determine if a proprietary aerobic treatment plant is appropriate for
use with surface application disposal it must
a . be on the TCEQ's most recently approved list
b . be able to maintain a minimum DO of 4.0 mg / L
c . have a volume equal to three times the expected daily flow
d . be certified by a PE or RS to provide 90 % or better treatment
......ANSWER......d . be certified by a PE or RS to provide 90 % or better
treatment
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To determine the minimum size of aerobic treatment plant needed for a
particular home , one must know d a . soil acceptance rate ( R₂
b aeration and clarifier volumes
c . rate of irrigation ( R ) from OSSF Rules
d . number of bedrooms in the home and refer to TCEQ Table II
......ANSWER......d number of bedrooms in the home and refer to TCEQ
Table II
Which of the following is a likely cause of a " rotten egg " odor from an
aerobic treatment plant ?
a . Chlorinator failure
b . Mechanical aerator failure
c . Failure to install a trash trap
d . Hydraulic overload caused by a leaking toilet ......ANSWER......b .
Mechanical aerator failure
and need for wasting ? Which of the following is a way of evaluating an
aerobic treatment plant for excessive solids
a . DO test .
b. BOD5 analysis
c . 30 - min . settling test
d . Chlorine residual test in mg / L ......ANSWER......c . 30 min . settling
test
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mg / L Which of the following is true of an intermittent sand filter ?
a . Provides secondary wastewater treatment
b Has a maximum surface loading rate of 1.2 gal./day/ft.2
c . Requires at least 24 in . of filter media that meets definite
specifications ( ASTM C - 33 )
d . All the above ......ANSWER......d . All the above
Trickling filters and wetlands
a . are anaerobic treatment systems b . are secondary treatment
processes
c . are widely used across Texas for OSSF treatment
d . rely on straining or filtering as the main treatment mechanism
......ANSWER......b . are secondary treatment processes
Which of the following considerations should receive the greatest
emphasis in selecting a type of OSSF system disposal option ?
a . System cost
b. Electrical rates
c . Soil and site conditions
d . Maintenance and service availability ......ANSWER......c . Soil and site
conditions
would include On a west Texas site with 16 in of Class Ia soil over
fractured rock suitable OSSF systems a . lined or unlined ETs
OSSF INSTALLER 2 Exam (updated 2026) Questions &
Answers | Latest Already Graded A+ UPDATE |2026
Which of the following is true of aerobic treatment plants ?
a . Able to maintain a minimum DO of 4.0 mg / L
b . Odor free , utilize aerobic bacteria and produce hydrogen sulfide gas
.
c. Use aerobic bacteria and oxygen to breakdown complex organics and
produce carbon dioxide
d . Use aerobic bacteria and carbon dioxide to produce complex organic
compounds and natural gas ......ANSWER......c . Use aerobic bacteria and
oxygen to breakdown complex organics and produce carbon dioxide
To determine if a proprietary aerobic treatment plant is appropriate for
use with surface application disposal it must
a . be on the TCEQ's most recently approved list
b . be able to maintain a minimum DO of 4.0 mg / L
c . have a volume equal to three times the expected daily flow
d . be certified by a PE or RS to provide 90 % or better treatment
......ANSWER......d . be certified by a PE or RS to provide 90 % or better
treatment
,2|Page
To determine the minimum size of aerobic treatment plant needed for a
particular home , one must know d a . soil acceptance rate ( R₂
b aeration and clarifier volumes
c . rate of irrigation ( R ) from OSSF Rules
d . number of bedrooms in the home and refer to TCEQ Table II
......ANSWER......d number of bedrooms in the home and refer to TCEQ
Table II
Which of the following is a likely cause of a " rotten egg " odor from an
aerobic treatment plant ?
a . Chlorinator failure
b . Mechanical aerator failure
c . Failure to install a trash trap
d . Hydraulic overload caused by a leaking toilet ......ANSWER......b .
Mechanical aerator failure
and need for wasting ? Which of the following is a way of evaluating an
aerobic treatment plant for excessive solids
a . DO test .
b. BOD5 analysis
c . 30 - min . settling test
d . Chlorine residual test in mg / L ......ANSWER......c . 30 min . settling
test
, 3|Page
mg / L Which of the following is true of an intermittent sand filter ?
a . Provides secondary wastewater treatment
b Has a maximum surface loading rate of 1.2 gal./day/ft.2
c . Requires at least 24 in . of filter media that meets definite
specifications ( ASTM C - 33 )
d . All the above ......ANSWER......d . All the above
Trickling filters and wetlands
a . are anaerobic treatment systems b . are secondary treatment
processes
c . are widely used across Texas for OSSF treatment
d . rely on straining or filtering as the main treatment mechanism
......ANSWER......b . are secondary treatment processes
Which of the following considerations should receive the greatest
emphasis in selecting a type of OSSF system disposal option ?
a . System cost
b. Electrical rates
c . Soil and site conditions
d . Maintenance and service availability ......ANSWER......c . Soil and site
conditions
would include On a west Texas site with 16 in of Class Ia soil over
fractured rock suitable OSSF systems a . lined or unlined ETs
