Water Treatment Class D Study Guide Exam
Test Practice Questions & Answers
The two most important factors impacting the effectiveness of chlorination are? - ANS ✔ -
Concentration of chlorine and contact time
The treatment process that controls corrosion or scaling is known as? - ANS ✔ - stabilization
Permanganate reactions are highly dependent upon? - ANS ✔ - pH
It is hardest to kill the organism that causes which of the following illness? - ANS ✔ -
Cryptosporidiosis
Disinfection of water wells with free chlorine requires exposure for___ at a concentration of___. - ANS
✔ - 12 to 24 hours; 50mg/L
Detention time in flocculation basins are usually designed to provide for? - ANS ✔ - 15 to 45 min.
Alum works best in a pH range of - ANS ✔ - 5.8-7.5.
Which statement is true concerning colloidal particles? - ANS ✔ - Colloidal particles are so small that
gravity has little effect on them
Which natural electrical force keeps colloidal particles apart in water treatment? - ANS ✔ - zeta
potential.
The zeta potential measures the number of excess found on the surface of all particular matter. - ANS
✔ - Electrons.
Which device collects the settled water as it leaves the sedimentation basin? - ANS ✔ - Effluent
launder
, Water Treatment Class D Study Guide Exam
Test Practice Questions & Answers
In solid-contact basins with fairly constant water quality parameters, how often should the solids
concentration be determined? - ANS ✔ - At least twice per day
The definition of decant is? - ANS ✔ - to draw off the liquid from a vessel of any size without stirring
up the bottom sediment
How often should sedimentation basins with mechanical sludge removal equipment be drained and
inspected? - ANS ✔ - once a year
Which is the most important reason to reduce turbidity? - ANS ✔ - To remove pathogens
Which is the filtration flow rate through a manganese greensand pressure filter at 10•C? - ANS ✔ - 2
to 3 got/ft2
When a filter is ripening - ANS ✔ - it is becoming more efficient in particle removal
Virgin greensand can be regenerated by soaking the filter bed for several hours in a solution of
chlorine containing - ANS ✔ - 100mg/L Cl2
Which role does the action of straining of suspended particles play during filtration? - ANS ✔ - minor
The turbidity of settled water before it is applied to the filters (post sedimentation process) should
always be kept below - ANS ✔ - 1 to 2 ntu
Which precipitates can foul a cation exchange resin? - ANS ✔ - Iron and manganese
Which process works best for sequestering manganese? - ANS ✔ - Polyphosphates and chlorine
Test Practice Questions & Answers
The two most important factors impacting the effectiveness of chlorination are? - ANS ✔ -
Concentration of chlorine and contact time
The treatment process that controls corrosion or scaling is known as? - ANS ✔ - stabilization
Permanganate reactions are highly dependent upon? - ANS ✔ - pH
It is hardest to kill the organism that causes which of the following illness? - ANS ✔ -
Cryptosporidiosis
Disinfection of water wells with free chlorine requires exposure for___ at a concentration of___. - ANS
✔ - 12 to 24 hours; 50mg/L
Detention time in flocculation basins are usually designed to provide for? - ANS ✔ - 15 to 45 min.
Alum works best in a pH range of - ANS ✔ - 5.8-7.5.
Which statement is true concerning colloidal particles? - ANS ✔ - Colloidal particles are so small that
gravity has little effect on them
Which natural electrical force keeps colloidal particles apart in water treatment? - ANS ✔ - zeta
potential.
The zeta potential measures the number of excess found on the surface of all particular matter. - ANS
✔ - Electrons.
Which device collects the settled water as it leaves the sedimentation basin? - ANS ✔ - Effluent
launder
, Water Treatment Class D Study Guide Exam
Test Practice Questions & Answers
In solid-contact basins with fairly constant water quality parameters, how often should the solids
concentration be determined? - ANS ✔ - At least twice per day
The definition of decant is? - ANS ✔ - to draw off the liquid from a vessel of any size without stirring
up the bottom sediment
How often should sedimentation basins with mechanical sludge removal equipment be drained and
inspected? - ANS ✔ - once a year
Which is the most important reason to reduce turbidity? - ANS ✔ - To remove pathogens
Which is the filtration flow rate through a manganese greensand pressure filter at 10•C? - ANS ✔ - 2
to 3 got/ft2
When a filter is ripening - ANS ✔ - it is becoming more efficient in particle removal
Virgin greensand can be regenerated by soaking the filter bed for several hours in a solution of
chlorine containing - ANS ✔ - 100mg/L Cl2
Which role does the action of straining of suspended particles play during filtration? - ANS ✔ - minor
The turbidity of settled water before it is applied to the filters (post sedimentation process) should
always be kept below - ANS ✔ - 1 to 2 ntu
Which precipitates can foul a cation exchange resin? - ANS ✔ - Iron and manganese
Which process works best for sequestering manganese? - ANS ✔ - Polyphosphates and chlorine
