How does primary treatment usually handle the removed debris post-processing?

In primary treatment of wastewater, the process typically involves the physical separation of solids from the liquid. After the removal of these solids, which can include debris and other larger particulate matter, the accepted practice for handling the removed materials is to send them to a landfill. This is because the collected solids, often referred to as primary sludge, can contain a variety of contaminants that are not suitable for recycling or reintroduction into the treatment process.

Option C reflects the standard approach of managing the residual solids by disposing of them in a landfill, which is designed to safely contain waste materials without creating environmental hazards. This method ensures that the pollutants do not re-enter the environment or the treatment system, thereby maintaining the efficiency and effectiveness of the overall wastewater treatment process.

While other disposal methods may be discussed in different contexts, in the case of primary treatment, landfill disposal remains the most appropriate and widely practiced method for handling the debris that is removed.