What is the principle mechanism underlying a grease trap's operation?

The principle mechanism underlying a grease trap's operation involves the ability of low-density substances, such as grease, to float on the surface of water. In a grease trap, wastewater flows into a chamber where the grease, being less dense than water, rises to the top. This separation is critical because it prevents the grease from entering the sewage system, where it could cause blockages and other issues.

The design of a grease trap facilitates this process by providing a space for the grease to accumulate while allowing the denser wastewater to flow out to the sewer system below. The effectiveness of a grease trap relies on this buoyancy principle, which is why the chosen answer accurately reflects the key mechanism involved in its operation.

In contrast, other options discuss either the dissolution of grease in water, which does not occur in significant amounts, or filtration methods that do not represent the primary way a grease trap functions. The concept of density and floatation is essential to understanding how grease traps effectively remove fats, oils, and greases from wastewater.