What is the first stage in sewage treatment?

The first stage in sewage treatment is screening and grit removal. This initial process is crucial for ensuring that larger debris and solids that could interfere with the subsequent treatment stages are effectively filtered out. During screening, various types of barriers are used to catch larger objects such as plastic, leaves, and other materials. Once these are removed, grit removal acts to settle out sand, silt, and other dense particles.

By removing these substances early in the treatment process, the remaining sewage can be processed more efficiently in subsequent stages, such as sedimentation and aerobic biological treatment. This also helps to protect the equipment used in later processes from damage or clogging, making the entire treatment system more effective and economical.