What is a key feature of grease traps used in sewage systems?

A key feature of grease traps in sewage systems is that they must be regularly emptied to function effectively. Grease traps work by capturing grease, fats, and oils that are discharged from kitchens and food service establishments. Over time, as these substances accumulate, they can reduce the effectiveness of the trap, leading to potential plumbing issues, backups, and environmental concerns.

Regular maintenance, including periodic emptying, is essential to ensure that the grease trap continues to perform its intended function of preventing grease from entering the main sewer system. If not emptied, the accumulated grease can overflow, allowing these materials to reach the larger sewage system, which can cause clogs and damage.

The other choices highlight features that are less critical or incorrect regarding grease traps. For example, while grease traps do filter out some solids, their primary function is not to filter large solids but to separate grease. The material used to construct grease traps can vary, and while they can be made from specific approved materials, they are not unrestricted. Lastly, grease traps are indeed used in residential settings, particularly in homes with kitchens that generate substantial grease.