OSSF DR(DESIGNATED
REPRESENTATIVE) TEST
PRACTICE
The standard drainfield depth in East and Central Texas is limited to -
ANSWERS-18 inches minimum and 36 inches maximum
The minimum distance between standard drainfield excavations is -
ANSWERS-3 feet
Grease interceptors are needed - ANSWERS-on wastewater lines
from commercial kitchens
Which of the following is true if porous media in a standard
drainfield? - ANSWERS-It should be uniform in size, it should be
0.75 inch to 2 inches in size, it should be clean and resistant to
breakdown
A standard drainfield excavation should - ANSWERS-be level within
1 inch per 25 feet or a maximum of 3 inches whichever is less
A standard perforated drainline should be which of the following? -
ANSWERS-3 inches to 4 inches in diameter, a maximum length of
150 feet, laid parallel in multiple-line system
,The purpose of the geotextile fabric over gravel is to - ANSWERS-
prevent backfill from entering porous media
A pumped effluent drainfield - ANSWERS-is an alternative for well-
drained clay soils on nearly level sites, has a 2% or less slope for
single-family dwellings only
Which of the following must be known prior to actually laying out a
new OSSF? - ANSWERS-building location, size of the property, soil
conditions in the drainfield
In an unlined ET system, wastewater is disposed of by which of the
following? - ANSWERS-evaporation, transpiration, soil absorption
A gravelless pipe drainfield - ANSWERS-can be backfilled with Class
Ib, II, or III soil
A leaching chamber system - ANSWERS-requires 25% less
absorptive area than a standard system for new construction
Aerobic treatment units - ANSWERS-utilize aerobic bacteria and
oxygen to break down complex organics and produce carbon dioxide
To determine if a proprietary aerobic treatment unit is appropriate for
use with surface application disposal it must - ANSWERS-be on the
TCEQ's most recently approved list
, To determine the minimum size of aerobic treatment unit needed for a
particular home, one must know - ANSWERS-number of bedrooms
and square feet 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? - ANSWERS-Mechanical aerator failure,
hydraulic overload caused by leaking toilet
Which of the following is a way to evaluate an aerobic treatment plant
for excessive solids and need for wasting? - ANSWERS-30-minute
settling test
Which of the following is true of standard intermittent sand filter? -
ANSWERS-provides secondary wastewater treatment, has a
maximum surface loading rate of 1.2 gal/day/sqft, requires at least 24
inches of filter media which meets definite specifications (ASTM C-
33)
When would an intermittent sand filter with disinfection system be
selected over a properly designed and installed septic tank system? -
ANSWERS-For a standard drainfield in class Ia soil
Trickling filters and wetlands - ANSWERS-are secondary treatment
processes
Which of the following considerations should receive the greatest
emphasis in selecting a type of OSSF disposal option? - ANSWERS-
soil and site conditions
REPRESENTATIVE) TEST
PRACTICE
The standard drainfield depth in East and Central Texas is limited to -
ANSWERS-18 inches minimum and 36 inches maximum
The minimum distance between standard drainfield excavations is -
ANSWERS-3 feet
Grease interceptors are needed - ANSWERS-on wastewater lines
from commercial kitchens
Which of the following is true if porous media in a standard
drainfield? - ANSWERS-It should be uniform in size, it should be
0.75 inch to 2 inches in size, it should be clean and resistant to
breakdown
A standard drainfield excavation should - ANSWERS-be level within
1 inch per 25 feet or a maximum of 3 inches whichever is less
A standard perforated drainline should be which of the following? -
ANSWERS-3 inches to 4 inches in diameter, a maximum length of
150 feet, laid parallel in multiple-line system
,The purpose of the geotextile fabric over gravel is to - ANSWERS-
prevent backfill from entering porous media
A pumped effluent drainfield - ANSWERS-is an alternative for well-
drained clay soils on nearly level sites, has a 2% or less slope for
single-family dwellings only
Which of the following must be known prior to actually laying out a
new OSSF? - ANSWERS-building location, size of the property, soil
conditions in the drainfield
In an unlined ET system, wastewater is disposed of by which of the
following? - ANSWERS-evaporation, transpiration, soil absorption
A gravelless pipe drainfield - ANSWERS-can be backfilled with Class
Ib, II, or III soil
A leaching chamber system - ANSWERS-requires 25% less
absorptive area than a standard system for new construction
Aerobic treatment units - ANSWERS-utilize aerobic bacteria and
oxygen to break down complex organics and produce carbon dioxide
To determine if a proprietary aerobic treatment unit is appropriate for
use with surface application disposal it must - ANSWERS-be on the
TCEQ's most recently approved list
, To determine the minimum size of aerobic treatment unit needed for a
particular home, one must know - ANSWERS-number of bedrooms
and square feet 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? - ANSWERS-Mechanical aerator failure,
hydraulic overload caused by leaking toilet
Which of the following is a way to evaluate an aerobic treatment plant
for excessive solids and need for wasting? - ANSWERS-30-minute
settling test
Which of the following is true of standard intermittent sand filter? -
ANSWERS-provides secondary wastewater treatment, has a
maximum surface loading rate of 1.2 gal/day/sqft, requires at least 24
inches of filter media which meets definite specifications (ASTM C-
33)
When would an intermittent sand filter with disinfection system be
selected over a properly designed and installed septic tank system? -
ANSWERS-For a standard drainfield in class Ia soil
Trickling filters and wetlands - ANSWERS-are secondary treatment
processes
Which of the following considerations should receive the greatest
emphasis in selecting a type of OSSF disposal option? - ANSWERS-
soil and site conditions
