Designated Representative OSSF
EXAM QUESTIONS WITH CORRECT
SOLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED
A+||<<LATEST VERSION>>
The purpose of a clarifier in aerobic systems is - ANSWER ✓ to provide a stilling
zone to settle out and separate activated sludge from wastewater
An operational test of an aerobic system includes - ANSWER ✓ ensuring air is
entering and mixing in the aeration vessel, activating pumps and high-water alarms
to ensure operational
The installer is required to make available to the owner a copy of - ANSWER ✓
the manufacturers owner's manual, the OSSF maintenance and management
practices in Section 285.39.
The compressor of an aerobic unit should be checked - ANSWER ✓ daily
Aerobic systems require maintenance agreements at what frequency? - ANSWER
✓ Initial 2 year contract, then can be self maintained
The majority of aerobic systems utilize what method of disposal - ANSWER ✓
surface application
The complete system check of an aerobic unit includes - ANSWER ✓ -the
compressor
-checking warning lights, audible alarms, motor malfunction
-rotten egg odor
-filters associated with compressor
,Surface application systems and secondary treatment systems must be tested at
what frequency - ANSWER ✓ 4 months
Site visits/tests may be reduced to twice a year if - ANSWER ✓ systems have
electronic monitoring and automatic telephone or radio access
Tests to be performed for all surface application systems include - ANSWER ✓
Total Chlorine Residual or Fecal Coliform, minimum chlorine residual .1mg/L,
maximum fecal coliform 200mpn/100mL
Commercial and institutional facilities are required to have an annual grab sample
analyzed for - ANSWER ✓ BOD and TSS, both cannot exceed 65mg/L
A testing and reporting form must be filled out with each visit and a copy
submitted to the regulatory authority within - ANSWER ✓ 10 days
30 Minute settling test - ANSWER ✓ sludge volume should read between 20%
and 60% on a well-operating aeration plant. Should be composed of brown,
clumpy flock that settles gently
If the sludge volume approaches 70% - ANSWER ✓ waste sludge but do not
pump dry in aerobic system, leave 15% in 30 minute settling test
Sand Filtration - ANSWER ✓ A secondary treatment unit, used when conditions
exist that restrict soil absorption
Intermittent Sand Filtration - ANSWER ✓ Involves a single pass of effluent
through filter media and reduces BOD to 2-23mg/L and TSS to 3-13mg/L
Recirculating Sand Filtration - ANSWER ✓ return 50-75% of treated effluent
back to primary treatment tank. Lowers BOD by 98% and TSS by 90%. Also
reduces nitrate by 60%
Construction requirements for Sand systems - ANSWER ✓ primary treatment
septic tank, pump tank, high-water alarms, floats, controls, sand media, filter bed
containment, underdrains
, Pump tank sizing - ANSWER ✓ Should be sized for 1/3 day of flow above the
alarm "on" level. may be reduced to 4 hours when pump tank is equipped with
multiple pumps
Multiple pumps are required when - ANSWER ✓ Q is greater than 1000 GPD
Filter bed containment requirements - ANSWER ✓ -liners of rubber or plastic of
at least 20mm cushioned with 4" of sand
-1' of concrete, gunite, compacted clay
-permeability of 10^-7 cm/sec or less
Filter bed construction - ANSWER ✓ -underdrains laid no more than 1/8" fall per
foot
-one line for no less than 1 foot
-min 6" covering of 3/4" washed gravel
-min 3" covering of 3/8" washed pea gravel
-min 24" sand meeting ASTM C-33 specs
Distribution pipe to filter bed requirements - ANSWER ✓ -geotextile filter fabric
to prevent mixing of layers
-centered in 9" layer of washed porous material (gravel or tire chips)
-One line for every 2 feet or less
-6-12" loamy topsoil seeded with grass
Trickling Filters - ANSWER ✓ use larger media consisting of rock, cinder, tire
chips, or plastic forms to harbor bacteria. Effluent is sprayed over media and
trickles down. maintains an aerobic environment
Wetlands - ANSWER ✓ Free Water Surface Wetlands
-waterproof reservoir, vegetation growth media, shallow water flowing through the
system
Subsurface Wetlands
-water surface is below the top of vegetation growth media
Pump tanks are routinely required for - ANSWER ✓ -LP drainfield
-Surface application
-Drip irrigation
EXAM QUESTIONS WITH CORRECT
SOLUTIONS||100% GUARANTEED
PASS||UPDATED 2026/2027
SYLLABUS||ALREADY GRADED
A+||<<LATEST VERSION>>
The purpose of a clarifier in aerobic systems is - ANSWER ✓ to provide a stilling
zone to settle out and separate activated sludge from wastewater
An operational test of an aerobic system includes - ANSWER ✓ ensuring air is
entering and mixing in the aeration vessel, activating pumps and high-water alarms
to ensure operational
The installer is required to make available to the owner a copy of - ANSWER ✓
the manufacturers owner's manual, the OSSF maintenance and management
practices in Section 285.39.
The compressor of an aerobic unit should be checked - ANSWER ✓ daily
Aerobic systems require maintenance agreements at what frequency? - ANSWER
✓ Initial 2 year contract, then can be self maintained
The majority of aerobic systems utilize what method of disposal - ANSWER ✓
surface application
The complete system check of an aerobic unit includes - ANSWER ✓ -the
compressor
-checking warning lights, audible alarms, motor malfunction
-rotten egg odor
-filters associated with compressor
,Surface application systems and secondary treatment systems must be tested at
what frequency - ANSWER ✓ 4 months
Site visits/tests may be reduced to twice a year if - ANSWER ✓ systems have
electronic monitoring and automatic telephone or radio access
Tests to be performed for all surface application systems include - ANSWER ✓
Total Chlorine Residual or Fecal Coliform, minimum chlorine residual .1mg/L,
maximum fecal coliform 200mpn/100mL
Commercial and institutional facilities are required to have an annual grab sample
analyzed for - ANSWER ✓ BOD and TSS, both cannot exceed 65mg/L
A testing and reporting form must be filled out with each visit and a copy
submitted to the regulatory authority within - ANSWER ✓ 10 days
30 Minute settling test - ANSWER ✓ sludge volume should read between 20%
and 60% on a well-operating aeration plant. Should be composed of brown,
clumpy flock that settles gently
If the sludge volume approaches 70% - ANSWER ✓ waste sludge but do not
pump dry in aerobic system, leave 15% in 30 minute settling test
Sand Filtration - ANSWER ✓ A secondary treatment unit, used when conditions
exist that restrict soil absorption
Intermittent Sand Filtration - ANSWER ✓ Involves a single pass of effluent
through filter media and reduces BOD to 2-23mg/L and TSS to 3-13mg/L
Recirculating Sand Filtration - ANSWER ✓ return 50-75% of treated effluent
back to primary treatment tank. Lowers BOD by 98% and TSS by 90%. Also
reduces nitrate by 60%
Construction requirements for Sand systems - ANSWER ✓ primary treatment
septic tank, pump tank, high-water alarms, floats, controls, sand media, filter bed
containment, underdrains
, Pump tank sizing - ANSWER ✓ Should be sized for 1/3 day of flow above the
alarm "on" level. may be reduced to 4 hours when pump tank is equipped with
multiple pumps
Multiple pumps are required when - ANSWER ✓ Q is greater than 1000 GPD
Filter bed containment requirements - ANSWER ✓ -liners of rubber or plastic of
at least 20mm cushioned with 4" of sand
-1' of concrete, gunite, compacted clay
-permeability of 10^-7 cm/sec or less
Filter bed construction - ANSWER ✓ -underdrains laid no more than 1/8" fall per
foot
-one line for no less than 1 foot
-min 6" covering of 3/4" washed gravel
-min 3" covering of 3/8" washed pea gravel
-min 24" sand meeting ASTM C-33 specs
Distribution pipe to filter bed requirements - ANSWER ✓ -geotextile filter fabric
to prevent mixing of layers
-centered in 9" layer of washed porous material (gravel or tire chips)
-One line for every 2 feet or less
-6-12" loamy topsoil seeded with grass
Trickling Filters - ANSWER ✓ use larger media consisting of rock, cinder, tire
chips, or plastic forms to harbor bacteria. Effluent is sprayed over media and
trickles down. maintains an aerobic environment
Wetlands - ANSWER ✓ Free Water Surface Wetlands
-waterproof reservoir, vegetation growth media, shallow water flowing through the
system
Subsurface Wetlands
-water surface is below the top of vegetation growth media
Pump tanks are routinely required for - ANSWER ✓ -LP drainfield
-Surface application
-Drip irrigation
