Minnesota Subsurface Sewage
Treatment System Designer Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a subsurface sewage treatment system
(SSTS)?
A. To disinfect drinking water
B. To treat and disperse wastewater into soil
C. To store stormwater runoff
D. To recycle industrial chemicals
Answer: B
Rationale: SSTS systems are designed to treat wastewater and safely
disperse it into the soil environment for final treatment.
2. Which soil characteristic most directly affects effluent treatment in an
SSTS?
A. Color
, B. Texture
C. pH only
D. Temperature
Answer: B
Rationale: Soil texture determines pore size and infiltration capacity,
which directly affects treatment and movement of effluent.
3. The Minnesota SSTS program is primarily regulated by which agency?
A. EPA
B. Minnesota Pollution Control Agency (MPCA)
C. USDA
D. CDC
Answer: B
Rationale: The MPCA oversees SSTS regulations in Minnesota.
4. What is the main function of a septic tank?
A. Aerobic treatment
B. Primary treatment through settling and anaerobic digestion
C. UV disinfection
D. Evaporation of wastewater
Answer: B
Rationale: Septic tanks provide primary treatment by allowing solids
to settle and undergo anaerobic decomposition.
5. Which soil structure is most suitable for SSTS infiltration?
A. Massive clay
, B. Well-graded sand
C. Bedrock
D. Frozen soil
Answer: B
Rationale: Well-graded sandy soils allow adequate infiltration and
treatment of effluent.
6. A percolation test measures:
A. Water pH
B. Soil nutrient content
C. Water absorption rate of soil
D. Oxygen levels in soil
Answer: C
Rationale: Percolation tests measure how quickly water moves
through soil.
7. Which is a key factor in determining SSTS design flow?
A. Home color
B. Number of bedrooms
C. Roof size
D. Garage size
Answer: B
Rationale: Design flow is typically based on the number of bedrooms
as a proxy for occupancy.
, 8. What is the purpose of a distribution device in an SSTS?
A. Store effluent
B. Evenly distribute effluent to the soil treatment area
C. Pump raw sewage
D. Disinfect wastewater
Answer: B
Rationale: Distribution devices ensure equal loading across the soil
treatment system.
9. Which system is best for high groundwater conditions?
A. Gravity trench system
B. Mound system
C. Direct discharge system
D. Open ditch system
Answer: B
Rationale: Mound systems elevate treatment areas above high
groundwater levels.
10. Soil loading rates are based primarily on:
A. Soil color
B. Soil texture and structure
C. Pipe material
D. Tank shape
Answer: B
Treatment System Designer Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. What is the primary purpose of a subsurface sewage treatment system
(SSTS)?
A. To disinfect drinking water
B. To treat and disperse wastewater into soil
C. To store stormwater runoff
D. To recycle industrial chemicals
Answer: B
Rationale: SSTS systems are designed to treat wastewater and safely
disperse it into the soil environment for final treatment.
2. Which soil characteristic most directly affects effluent treatment in an
SSTS?
A. Color
, B. Texture
C. pH only
D. Temperature
Answer: B
Rationale: Soil texture determines pore size and infiltration capacity,
which directly affects treatment and movement of effluent.
3. The Minnesota SSTS program is primarily regulated by which agency?
A. EPA
B. Minnesota Pollution Control Agency (MPCA)
C. USDA
D. CDC
Answer: B
Rationale: The MPCA oversees SSTS regulations in Minnesota.
4. What is the main function of a septic tank?
A. Aerobic treatment
B. Primary treatment through settling and anaerobic digestion
C. UV disinfection
D. Evaporation of wastewater
Answer: B
Rationale: Septic tanks provide primary treatment by allowing solids
to settle and undergo anaerobic decomposition.
5. Which soil structure is most suitable for SSTS infiltration?
A. Massive clay
, B. Well-graded sand
C. Bedrock
D. Frozen soil
Answer: B
Rationale: Well-graded sandy soils allow adequate infiltration and
treatment of effluent.
6. A percolation test measures:
A. Water pH
B. Soil nutrient content
C. Water absorption rate of soil
D. Oxygen levels in soil
Answer: C
Rationale: Percolation tests measure how quickly water moves
through soil.
7. Which is a key factor in determining SSTS design flow?
A. Home color
B. Number of bedrooms
C. Roof size
D. Garage size
Answer: B
Rationale: Design flow is typically based on the number of bedrooms
as a proxy for occupancy.
, 8. What is the purpose of a distribution device in an SSTS?
A. Store effluent
B. Evenly distribute effluent to the soil treatment area
C. Pump raw sewage
D. Disinfect wastewater
Answer: B
Rationale: Distribution devices ensure equal loading across the soil
treatment system.
9. Which system is best for high groundwater conditions?
A. Gravity trench system
B. Mound system
C. Direct discharge system
D. Open ditch system
Answer: B
Rationale: Mound systems elevate treatment areas above high
groundwater levels.
10. Soil loading rates are based primarily on:
A. Soil color
B. Soil texture and structure
C. Pipe material
D. Tank shape
Answer: B
