Using lower and upper baffle arrangements to enhance sedimentation tank performance

Abstract

Traditional sedimentation tanks are massive structures that needs require extensive detention times to allow the separation of particles from suspension by gravity. Many researchers have proposed methods of enhancing sedimentation efficiency, including changing the geometry of tanks by installing barriers at the bottom of the basin, in order to reduce demand for chemical processes, which require trained operators to determine the appropriate doses of coagulants. The aim of the current research was make the flow route longer and to distribute suspension over various sedimentation tank compartments in order to increase residence time and thus enhance sedimentation, with effects judges based on calculating the turbidity, density, and viscosity, Froude number (Fr), Reynolds number (Re), settling velocity (vs), detention time (D.T.), height of sludge (hs), and sediment removal. The theoretical aspects were supported by the collection of practical results through laboratory testing that showed that the best Fr, Re, and hs occurred in zone 3, where the opening height of the central baffle created a short-circuit that scoured the deposited particle, while the best turbidity removal occurred with the smallest discharge. The evidence overall suggested that adding both lower and upper baffles improves the performance of sedimentation tanks because this arrangement achieves two essential goals: lengthening the track and damping or calming the flow within the settling zone; however, this only occurs if the vertical upper baffle is situated in a suitable location.