Page 56 - Statistics presented by Dr. Sara Ismail Aborass

9/8/2023

CORROSION AND PLUMBO – SOLVENCY
Water acidity (low pH) and free oxygen are the main factors

causing corrosion and plumbo-solvency.
* Corrosion = solvent action of water on metals.
Corrosive waters : may cause pitting and even perforation of

water pipes made of iron or copper, thereby introducing the
metals into the water which impair water taste and purity.
Plumbo-Solvency = solvent action of water on lead

Plumbo-solvency is not demonstrated by visual changes in
water characters but it may cause an onset of lead poisoning
among consumers of such water (lead has a cumulative toxic
effect).

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Corrosion and plumbo-solvency can be avoided and
controlled by:

(i) Increasing pH by Ca(HCO3)2 which will precipitate
a protective calcium carbonate film on the inner
surface of the pipes.

Ca(HCO3)2 CaCO3 ↓ + CO2 ↑ + H2O

(ii) Addition of oxygen – absorbing substances.
(iii) Use of galvanized (zinc – coated) pipes.

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