TM 5-813-8
Cations Removed Per Gallons of Potable Water
(409 gallons) x
488 parts per million - 104.5 parts per million x 1 pound
kilogallon
17.1 parts per million/grains/gallon
7000 grains
= 1.31 pounds as CaCO3
1000 gallons potable water
At 200-percent regeneration efficiency:
Acid Required = 2.0 x
1.31 pounds as CaCO3
49 equivalent weight acid
kilogallons potable water
50 equivalent weight CaCO3
x
1 pound H2S04
.995 percent H2S04
= 2.58 pounds 99.5 percent H2SO4 per 1000 gallons potable water
Waste Acid
(2.0 - 1.0)1.29
pounds acid
1.29 pounds 99.5 percent H2S04
x
kilogallons potable water
1000 gallons potable water
Chemical Costs
Acid Cost = 3 cents/pound 99.5 percent H2S04
NaOH Cost = 10 cents/pound 100 percent NaOH
Regeneration Acid = 1.29 pounds 99.5 percent H2SO4
If neutralization of the waste acid is required prior to disposal:
Waste Acid = 1.29 pounds 99.5 percent H2S04
1000 gallons potable water
If we use 100 percent NaOH
40 equivalent weight NaOH
NaOH = 1.32 pounds of 100% acid as CaCO3 x 50 equivalent weight CaCO3
=
1.05 pounds of 100 percent NaOH
1000 gallons potable water
Summary of Cost Per 1000 Gallons of Potable Water
Cation exchange acid usage = 1.29 pounds x 3.0 cents = 3.87 cents
Waste acid = 1.29 pounds x 3.0 cents = 3.87 cents
Neutralization NaOH = 1.05 pounds x 10 cents = 10.5 cents
5 Pounds/Cubic Foot Regeneration Level
∴In 1000 gallons potable water
396 gallons raw water to 500 milligrams per liter of total dissolved
solids + (1000 - 396) x .37 = 223.5 gallons to neutralization
Or
396 + 223.5 = 619.5 gallons of raw water
And
380.5 gallons of cation effluent
So:
38 percent of potable water is treated with the cation exchanger
Acid Usage
Cation Regeneration Efficiency
A-29
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