Which stage of waste treatment is primarily concerned with the removal of larger solids?

The stage of waste treatment that focuses on the removal of larger solids is settling. In this process, waste water is allowed to sit undisturbed for a period, allowing larger particles and solids to settle to the bottom of the treatment tank due to gravity. This sedimentation process effectively separates heavier solids from the liquid portion of the waste, resulting in a clearer effluent above the settled solids.

Coagulation is a chemical process where chemicals are added to wastewater to bind smaller particles together into larger aggregates, making them easier to remove in subsequent processes. While important, it does not directly remove larger solids but rather prepares smaller particles for removal later.

Filtration involves passing water through a medium to remove smaller particles and contaminants, but it is not focused on the removal of bulk solids as those are typically already removed beforehand.

Disinfection is a process aimed at killing or inactivating pathogens in the water. It is usually one of the final steps in the treatment process and does not deal with solid removal.

Thus, settling is the key stage focused on eliminating larger solids from the wastewater treatment process.