Question

The first step in the sewage-treatment process is _____.

Answer 1

Primary treatment. In the primary sedimentation stage, sewage flows through large tanks, commonly called "pre-settling basins", "primary sedimentation tanks" or "primary clarifiers". The tanks are used to settle sludge while grease and oils rise to the surface and are skimmed off.

Answer 2

the correct answer is the screening of large particles