Dead Zone Analysis for Estimating Hydraulic Efficiency in Rectangular Disinfection Chlorine Contactors

Abstract

To increase disinfection potential in a chlorine contactor, it is often recommended to increase the detention time in the contactor, that is, its hydraulic efficiency. This can be accomplished by installing inner devices such as baffle walls, diffuser walls, and intrabasins. To more accurately analyze the effect of such inner devices, it is necessary to conduct transient hydrodynamic analysis, which is computationally intensive. To reduce this computational burden, this study develops a simplified approach using steady-state dead zone analysis. In addition, this study uses the simplified approach to explain, with an indicator of dead zone volume percentage, why hydraulic efficiency changes with using different designs of length/width ratio, shape factor, diffuser walls, and intrabasins. This study suggests a relationship between dead zone volume percentage and hydraulic efficiency to replace length/width ratio. This will increase the estimation accuracy of hydraulic efficiency with various designs of chlorine contactors while avoiding use of computationally intensive transient hydrodynamic analysis.