AWWA JAW10793

This article discusses cathodic protection methods for water storage tanks, which protect against corrosion and are economical over the long term. The following topics are addressed: the corrosion mechanism; the need for corrosion control; design of cathodic protection; electrolyte resistivity; anode materials; rectifiers; and maintenance. Automatically controlled, solid-state rectifiers, which measure the maintained potential without IR drop error, are recommended. Where icing conditions are encountered, a buoyant, long-lived anode system using platinized niobium wire is recommended, although replaceable aluminum anodes can also be used. High-silicon cast-iron anodes can be used for tanks when icing conditions do not exist. All systems must be properly maintained, however, to ensure continued effective operation and optimum corrosion control. Includes 11 references, table, figures.