Repeat Problem 5-10 using the three-bed system designed in Problem 5-7. Problem 5-10...

Repeat Problem 5-10 using the three-bed system designed in Problem 5-7.

Problem 5-10

Continuing the design of the ion exchange column for the Village of Dolomite, provide the following for the two-bed system that will operate in parallel with staggered regeneration cycles:

a. Surface loading rate (m³/d · m² )

b. Height and diameter of the resin bed

c. EBCT

d. Service fl ow rate (m³/d · m³ )

e. Height and diameter of the column vessel

f. Pressure drop

Assume the density of the resin is 850 kg/m³ (moist), a resin height less than or equal to 4.0 m, and that 50% expansion of the bed will be used during backwash. The pressure drop across the bed should be less than 140 kPa.

Problem 5-7

Repeat Problem 5-5 assuming a three-column system in series and operation of the “lead” column until the bed is exhausted. Assume the total out-of-service time is three hours.

Problem 5-5

A pilot scale ion exchange column was used to develop design data for a softening system for the Village of Dolomite. The data are shown below. The design flow rate is 7,000 m³/d. The design final hardness is 120 mg/L as CaCO₃ . Regeneration is to be once per day. The manufacturer’s operating capacity to breakthrough is 50%. Assume a two-column system and that there is no leakage before breakthrough. Use the mass balance technique to determine the mass of resin that will be required.