What are the two primary methods of corrosion protection mentioned for USTs?

The two primary methods of corrosion protection for underground storage tanks (USTs) are galvanic systems and impressed current systems. These methods are essential for preventing corrosion, which can lead to leaks and environmental contamination.

Galvanic systems utilize sacrificial anodes made of a more reactive metal than the tank itself. These anodes corrode instead of the tank, thereby providing a protective effect. The other method, impressed current systems, involves an external power source that continuously supplies a current to counteract the electrochemical reactions that lead to corrosion.

In the context of USTs, these systems are critical because they extend the life of the tank and prevent the release of stored materials into the environment, which can have serious consequences for soil and groundwater quality.

The other options describe various methods that may contribute to corrosion prevention but do not specifically address the two primary types focused on electrochemical corrosion protection. Chemicals and coatings may provide some level of protection but are not categorized as the main methods of corrosion protection. Similarly, plating and painting serve to protect surfaces, but they do not involve the electrochemical processes that galvanic and impressed current systems utilize.