The inclined tube settler is a high-efficiency modular sedimentation tank designed based on the shallow tank theory. Closely packed tubes or plates are installed in the settling zone, guiding the water flow and allowing suspended solids to settle onto the surfaces. The separated sludge slides down by gravity and is discharged from the bottom of the tank. Compared with conventional sedimentation tanks, this design increases settling efficiency by 50–60% or boosts treatment capacity by 3–5 times within the same footprint.