Use of three-dimensional computational fluid dynamics model for a new configuration of circular primary settling tank

Abstract Appropriately used, computational fluid dynamics models are powerful tools to design and optimize primary settling tanks (PSTs). This paper uses a Fluent-based 3D model identify the possible causes for underperformance of circular PSTs at Cali waste-water treatment plant, Colombia, propose modifications improve performance. A new configuration center well (CW) is proposed evaluated. The influence rotational sludge scraper continuous removal were considered in numerical simulation. included modification current CW diameter location second baffle with CW. results suggest that installation allows more uniform flow distribution within PST consequently, hydrodynamic problems associated short-circuiting influent bottom tank reduced. suppresses downward current, effectively dissipates kinetic energy forces particles move toward PST. In addition, formation inlet zone consistently concentrated blanket layer thicker sludge, reducing risk solids leaving effluent