Problem 11.1: A cooling tower suddenly shows higher

From Chapter 11 Problem Set. Level 1: Conceptual Mastery.

Question

A cooling tower suddenly shows higher conductivity, higher pH, and weaker oxidant residual. Before adjusting any feed pump, list:

• what may have changed in what enters?
• what may have changed in what leaves?
• what may now be accumulating?
• and what transformations may be occurring faster than before?

Answer

Show answer

Likely possibilities include:

• What enters: Makeup fraction may have increased, incoming solids may have increased, contamination may have entered, or inlet temperature may have changed.
• What leaves: Blowdown may have decreased, a valve may have failed, filtration may have lost effectiveness, or another removal pathway may have changed.
• What accumulates: Dissolved solids, deposits, biomass, and sludge may now be accumulating.
• What changes form: Bicarbonate may be shifting toward carbonate at higher pH, oxidant demand may be increasing through reaction with organics or biofilm, and dissolved species may be precipitating as solids.