Investigation of Rectangular Settling Tanks Performance in Drinking Water Treatment Plants.

Document Type : Research Studies

Authors

1 Eng. of Designs & Presentations (IETOS)

2 Water sector, Suez Canal Authority

3 Mechanical Power Engineering Department , Delta University for Science and Technology

Abstract

A uniform flow field is essential to increase the efficient performance of settling tank. This enables particles to settle at a constant velocity and in less time.  The existence of circulation regions reduces the sedimentation of particles and has major influence on the hydraulic condition of flow field inside the settling tanks. According to this, the existence of large circulation regions will reduce tank performance. A common approach for decreasing settling tanks problems is to use baffles at inlet which can reduce effects of the unfavorable phenomena such as short circuiting between inlet and outlet and density currents in settling tanks. The aim of this study is to investigate the performance of rectangular settling tanks in drinking water treatment plants numerically and experimentally. A computational model has been mapped to the commercial FLUENT® solver. Applied to simulate the flow within a 3D rectangular water settling tank with different inlet configurations where the optimum inlet design is selected. Also, a continuous flow bench scale settling tank is used to experimentally investigate the effect of inlet on the performance of the settling tank by measuring the water turbidity along the flow direction in the tank. The practical results validates the results given by CFD simulation where the performance of the tank is enhances using inlet baffles.

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