TCOT - Test 2: Softening Questions With Complete
Solutions
An ion exchange softener contains 35 cubic feet of resin with a
hardness removal capacity of 25 kilograins per cubic foot of
resin. The water being treated has a hardness of 250 milligrams
per liter as CaCO3. How many gallons of water can be softened
before the softener will require regeneration? Correct Answers
An ion exchange softener will remove 2,000,000 grains of
hardness before the resin becomes exhausted. If 0.5 pounds of
salt are required per 1,000 grains of hardness, how many pounds
of salt are needed? Correct Answers 1,000 lb of salt
Convert the hardness of a water at 320 milligrams per liter to
grains per gallon. Correct Answers 18.7 gpg
Determine the total hardness as CaCO3 (2.497) for a sample of
water with a calcium content of 50 milligrams per liter (mg/L)
and a magnesium (4.118) content of 10 mg/L. Correct Answers
166.2 mg/L as CaCO3
How can the concentration of chloride ions in milligrams per
liter be converted to CaCO3 equivalents? Correct Answers
Multiply by 1.41
How can the equivalent weight of most elements be calculated?
Correct Answers Divide the molecular weight by the valence
How does quicklime react with water? Correct Answers Gets
hot enough to cause burns
, How many hours can an ion exchange softening unit operate
when treating an average daily flow of 75 liters per second? The
unit is capable of softening 6,000,000 liters of water before
requiring regeneration. Correct Answers 22 h
How many milligrams of hardness per liter are there in a water
with 18 grains of hardness per gallon of water? Correct Answers
308 mg/L
How much soda ash is required in pounds per minute to remove
75 milligrams per liter of noncarbonate hardness as CaCO3 from
a flow of 3.4 million gallons per day? Correct Answers 1.6
lb/min
How should a softener unit be refilled after total shutdown and
maintenance? Correct Answers Slowly, from the bottom
How will increasing the alum or iron feed rate affect the lime
dosage? Correct Answers More lime will be required
In the softening process, what pH level is needed for the desired
chemical reactions to occur? Correct Answers 11
The alkalinity of a water is 125 milligrams per liter (mg/L) as
CaCO3 and the total hardness is 140 mg/L as CaCO3. What is
the noncarbonate hardness in mg/L as CaCO3? Correct Answers
15 mg/L as CaCO3
The optimum lime dosage from a jar test is 230 milligrams per
liter. If the flow rate to be treated is 9 million gallons per day,
Solutions
An ion exchange softener contains 35 cubic feet of resin with a
hardness removal capacity of 25 kilograins per cubic foot of
resin. The water being treated has a hardness of 250 milligrams
per liter as CaCO3. How many gallons of water can be softened
before the softener will require regeneration? Correct Answers
An ion exchange softener will remove 2,000,000 grains of
hardness before the resin becomes exhausted. If 0.5 pounds of
salt are required per 1,000 grains of hardness, how many pounds
of salt are needed? Correct Answers 1,000 lb of salt
Convert the hardness of a water at 320 milligrams per liter to
grains per gallon. Correct Answers 18.7 gpg
Determine the total hardness as CaCO3 (2.497) for a sample of
water with a calcium content of 50 milligrams per liter (mg/L)
and a magnesium (4.118) content of 10 mg/L. Correct Answers
166.2 mg/L as CaCO3
How can the concentration of chloride ions in milligrams per
liter be converted to CaCO3 equivalents? Correct Answers
Multiply by 1.41
How can the equivalent weight of most elements be calculated?
Correct Answers Divide the molecular weight by the valence
How does quicklime react with water? Correct Answers Gets
hot enough to cause burns
, How many hours can an ion exchange softening unit operate
when treating an average daily flow of 75 liters per second? The
unit is capable of softening 6,000,000 liters of water before
requiring regeneration. Correct Answers 22 h
How many milligrams of hardness per liter are there in a water
with 18 grains of hardness per gallon of water? Correct Answers
308 mg/L
How much soda ash is required in pounds per minute to remove
75 milligrams per liter of noncarbonate hardness as CaCO3 from
a flow of 3.4 million gallons per day? Correct Answers 1.6
lb/min
How should a softener unit be refilled after total shutdown and
maintenance? Correct Answers Slowly, from the bottom
How will increasing the alum or iron feed rate affect the lime
dosage? Correct Answers More lime will be required
In the softening process, what pH level is needed for the desired
chemical reactions to occur? Correct Answers 11
The alkalinity of a water is 125 milligrams per liter (mg/L) as
CaCO3 and the total hardness is 140 mg/L as CaCO3. What is
the noncarbonate hardness in mg/L as CaCO3? Correct Answers
15 mg/L as CaCO3
The optimum lime dosage from a jar test is 230 milligrams per
liter. If the flow rate to be treated is 9 million gallons per day,
