Guide Questions and Answers
3 types of wastewater - Answer-domestic (home, sewage, 100g/person/day), industrial,
municipal (domestic, commercial, industrial)... known as sewage
types of system disposal - Answer-onsite disposal (septic tanks or disposal fields) and
systems connecting many homes leading to sewage treatment plant
how septic systems fail - Answer-backup from tank or clogged leach field, inadequate
leach field
sewerage? - Answer-pipes, pumps, treatment plant
sewers? - Answer-pipes
3 types of sewers and purpose - Answer-sanitary (carry sewage), storm (carry runoff),
combined (carry runoff and sewage)
5 types of contaminants - Answer-biochemical oxygen demand, suspended solids,
nutrients, organisms, toxins
influent? effluent? - Answer-what flows in.... what flows out
receiving water? POTW? - Answer-body of water which effluent is discharged....publicly
owned treatment works
requirements for water treatment - Answer-at minimum, secondary treatment; > 85% of
BOD and SS removal and < 30 mg/L remaining BOD and SS
Schematic of general wastewater treatment facility process - Answer-influent,
preliminary, primary, secondary, tertiary?, advanced?, disinfection, effluent, receiving
water
objective and process of preliminary treatment? - Answer-objective: remove large
objects and protect equipment
process: bar screen (rack), comminuter (grinder), grit chamber (sand)
objective and process of primary treatment? - Answer-objective: remove settleable and
floatable material (remove 60% ss and 35% BOD)
Process: ranks and collect raw sludge and scum
describe secondary treatment - Answer-required by law (% of BOD and SS)