What is the role of sacrificial anodes in underground storage tank systems?

Sacrificial anodes play a critical role in the protection of underground storage tanks (USTs) through a process known as cathodic protection. These anodes are made from a more reactive metal than the material of the tank, typically zinc, magnesium, or aluminum. During electrochemical reactions, the sacrificial anodes corrode preferentially, which means they lose their material in a controlled manner while protecting the UST itself from corrosion.

By corroding before the tank materials, these anodes help to prevent rust and deterioration of the tank structure, extending the tank's lifespan and maintaining its integrity. This cathodic protection system is particularly important for metal tanks that are susceptible to corrosion when buried underground, where moisture and soil can accelerate degradation. Thus, the primary function of sacrificial anodes is to create a barrier of protection for the tank, ensuring that it remains functional and safe for storing hazardous materials.