Which of the following is an example of an approved method for tank abandonment?

The correct answer highlights an accepted method for tank abandonment in the context of environmental safety and regulatory compliance. When a tank is no longer in use, particularly underground tanks that previously stored petroleum or other hazardous materials, it’s essential to properly abandon the tank to prevent leakage or contamination of the surrounding soil and groundwater.

Filling the tank with sand allows it to remain stable, prevents potential collapse, and isolates any remaining contaminants within the tank. This method effectively removes empty tank voids and addresses the risk of future leaks by ensuring that the tank is filled with a non-hazardous material. Moreover, this approach complies with environmental regulations that aim to protect public health and the environment.

Other methods may not provide the same level of safety or may violate regulations. For instance, removing the tank completely, while a possible approach, can be costly and might disturb the soil, which could lead to the release of any remaining contaminants. Filling the tank with water alone doesn't adequately prevent future leakage or mitigate risks, and sealing and tamping might not be sufficient in isolating potential contaminants. Thus, filling the tank with sand represents a balanced approach to the needs for safety, practicality, and adherence to environmental standards.