ADEQ Water Treatment Grade 4 Practice Test 2026 – Comprehensive Exam Preparation

Sedimentation works by letting gravity pull heavier particles to the bottom of the basin. The solids that settle relatively quickly (settleable solids) are removed when water spends enough time in the basin and the flow is well distributed. Because these particles are readily captured by gravity in a properly designed basin, the removal efficiency for settleable solids is very high—usually a large majority. That’s why the best choice reflects a high percentage of these solids being removed. In practice, a few factors like flow short-circuiting or sludge buildup prevent perfect removal, but the aim is a very high capture of settleable solids.