Problem 3.9: Two cooling towers both read 2000 Scm
From Chapter 3 Problem Set. Level 3: System Integration.
Question
Two cooling towers both read 2,000 µS/cm conductivity. Tower A’s makeup is high in sodium chloride. Tower B’s makeup is high in calcium bicarbonate. Which tower faces a greater scaling risk, and why does identical conductivity not mean identical behavior?
Answer
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Identical conductivity means equal electrical conductance under the measurement conditions, not identical total ionic concentration or composition. Ion charge and mobility both affect the reading. Tower B faces the greater scaling risk because calcium and bicarbonate can concentrate and shift toward calcium carbonate precipitation, while sodium chloride generally remains soluble.