Concentrated Species at Cycles of Concentration

Calculates the concentration of a dissolved species in tower water given its makeup concentration and the cycles of concentration. Used to predict calcium and other scaling-species levels under different blowdown control conditions.

$$C_{tower}=C_{makeup}\times \text{COC}$$

Variables

Symbol	Meaning	Unit
$C_{tower}$	Concentration of the species in tower water	mg/L as CaCO3
$C_{makeup}$	Concentration of the species in makeup water	mg/L as CaCO3
$\text{COC}$	Cycles of concentration	dimensionless

Worked example

Makeup calcium = 80 mg/L as CaCO3. At 4 COC, tower calcium = 80 x 4 = 320 mg/L as CaCO3. If COC drifts to 6 from a blowdown failure, tower calcium = 80 x 6 = 480 mg/L as CaCO3, a 50% increase from one control failure.

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Part of The Blueprint of Water