The two most important factors impacting the effectiveness of chlorination are
a. pH of the water and the content of foreign substances in the water
b. concentration of chlorine and the content of foreign substances in the water
c. concentration of chlorine and contact time
d. pH and temperature of the wastewater - answer
The treatment process that controls corrosion or scaling is known as
a. chemical control
b. stabilization
c. passivation
d. corrosion kinetics - answer
Permanganate reactions are highly
dependent upon
a. organic in the water
b. pH
c. temperature
d. alkalinity - answer
It is hard to kill the organism that causes which one of the following illnesses?
a. Cholera
b. Typhoid
c. Cryptosporidiosis
d. Infectious hepatitis - answer
Disinfection go water wells with free chlorine requires exposure for _____ at a
concentration of ______.
a. 6 to 12 hours; 25 mg/L
b. 12 to 24 hours; 25 mg/L
c. 12 to 24 hours; 50 mg/L
d. 24 to 28 hours; 100 mg/L - answer
Detention time in flocculation basins are usually designed to provide for
a. 5 to 15 minutes.
b. 15 to 45 minutes.
c. 45 to 60 minutes.
d. 60 to 90 minutes. - answer
Alum works best in a pH range of
a. less than 4.0.
, b. 4.0 to 5.5.
c. 5.8 to 7.5.
d. Greater than 9.0. - answer
Which statement is true concerning colloidal particles?
a. Colloidal particles are so small that gravity has little effect on them
b. The zeta potential between colloidal particles is balanced by covalent bonding
c. Electrical phenomenon of colloidal particles predominate and control their behavior
d. The surface area of colloidal particles is very small compared to their mass - answer
Which natural electrical force keeps colloidal particles apart in water treatment?
a. van der Waals forces
b. Ionic forces
c. Zeta potential
d. Quantum forces - answer
The zeta potential measures the number of excess
found on the surface of
all particulate matter.
a. electrons
b. ions
c. cations
d. protons - answer
Which is the filtration flow rate through a manganese greensand pressure filter at
10℃?
a. 1 to 2 gpm/ft2
b. 2 to 3 gpm/ft2
c. 3 to 5 gpm/ft2
d. 5 to 8 gpm/ft2 - answer
When a filter is ripening,
a. it is in need of a backwash.
b. turbidity is just starting to break through.
c. it is becoming more efficient in particle removal.
d. it is beginning to grow algae in the filter bed, walls, and troughs. - answer
Virgin greensand can be regenerated by soaking the filter bed for several hours in a
solution of chlorine containing
a. 50 mg/L CI,.
b. 75 mg/L Cl.
c. 100 mg/L CI,.
d. 200 mg/L CI,. - answer
Which role does the action of straining of suspended particles play during filtration?
a. Minor
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