OSTDS (ACT I) PART A BASIC
CONCEPTS IN WASTEWATER
TREATMENT. EXAM 2025 QUESTIONS
AND ANSWERS
Onsite disposal systems are a source of? - ANS groundwater recharge
Public health and environmental protection officials acknowledge that onsite systems are just
temporary installations that will be replaced eventually by centralized sewage treatment
services (T/F) - ANS False, these systems are acknowledged as permanent approaches.
There are 2.67 million septic systems and 8.8 million housing units (greater than 30% septic) in
Florida (T/F) - ANS True
How much urine does the average human create? - ANS 1.25 L (0.33 gallons) urine per day
How much feces does the average human create? - ANS 0.25 Kg (0.55 LB.) feces per day
bacteria per gram of feces? - ANS 10^12 bacteria per gram
Main elements found in body waste? - ANS Organic material 118 g
Nitrogen 16 g
Phosphorus 2 g
Other 14 g
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, What housing portion causes the most water use per day? - ANS TOILET (26.7% 18.5gpcd)
What housing portion causes the most gallons per use? - ANS WASHING MACHINE (21.7%,
15gpcd)
BOD (Biochemical Oxygen Demand) - ANS Measures the amount of dissolved oxygen
organisms need to degrade wastes in wastewater
TSS (Total Suspended Solids) - ANS A portion of wastewater that has resisted settling, that is
retained when passed through a filter. Also indicates wastewater clarity.
3 forms of nitrogen commonly measured: - ANS ammonia (NH4), nitrates (NO3) and
nitrites (NO2)
Fecal Coliform - ANS Used as indicator organism for the presence of pathogens and used to
determine if wastewater has been adequately treated
FOG - ANS (Fats, Oils and Greases) can increase BOD
Influent Wastewater Concentrations: (DOC) - ANS 110 mg/l
Influent Wastewater Concentrations: (BOD) - ANS 420 mg/l
Influent Wastewater Concentrations: (TS) - ANS 1028 mg/l
Influent Wastewater Concentrations: (TSS) - ANS 232 mg/l
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 2
CONCEPTS IN WASTEWATER
TREATMENT. EXAM 2025 QUESTIONS
AND ANSWERS
Onsite disposal systems are a source of? - ANS groundwater recharge
Public health and environmental protection officials acknowledge that onsite systems are just
temporary installations that will be replaced eventually by centralized sewage treatment
services (T/F) - ANS False, these systems are acknowledged as permanent approaches.
There are 2.67 million septic systems and 8.8 million housing units (greater than 30% septic) in
Florida (T/F) - ANS True
How much urine does the average human create? - ANS 1.25 L (0.33 gallons) urine per day
How much feces does the average human create? - ANS 0.25 Kg (0.55 LB.) feces per day
bacteria per gram of feces? - ANS 10^12 bacteria per gram
Main elements found in body waste? - ANS Organic material 118 g
Nitrogen 16 g
Phosphorus 2 g
Other 14 g
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 1
, What housing portion causes the most water use per day? - ANS TOILET (26.7% 18.5gpcd)
What housing portion causes the most gallons per use? - ANS WASHING MACHINE (21.7%,
15gpcd)
BOD (Biochemical Oxygen Demand) - ANS Measures the amount of dissolved oxygen
organisms need to degrade wastes in wastewater
TSS (Total Suspended Solids) - ANS A portion of wastewater that has resisted settling, that is
retained when passed through a filter. Also indicates wastewater clarity.
3 forms of nitrogen commonly measured: - ANS ammonia (NH4), nitrates (NO3) and
nitrites (NO2)
Fecal Coliform - ANS Used as indicator organism for the presence of pathogens and used to
determine if wastewater has been adequately treated
FOG - ANS (Fats, Oils and Greases) can increase BOD
Influent Wastewater Concentrations: (DOC) - ANS 110 mg/l
Influent Wastewater Concentrations: (BOD) - ANS 420 mg/l
Influent Wastewater Concentrations: (TS) - ANS 1028 mg/l
Influent Wastewater Concentrations: (TSS) - ANS 232 mg/l
COPYRIGHT © 2025 THESTAR ALL RIGHTS RESERVED 2
