Author(s): Riza Inanda Siregar; Bruno Fraga

Linked Author(s): Riza Inanda Siregar

Keywords: Naerobic baffled reactor; CFD modeling; Mixing processes; Particle image velocimetry; Wastewater treatment

Abstract: This work aims to optimize the design of ABRs through combined numerical and experimental testing. Particular emphasis is made on exploring the influence of the baffle configuration on the mixing performance. Numerical simulations resolving the 3D Navier-Stokes equations and the evolution of passive tracer are performed for this purpose. The simulations are run with different flow rates and validated with the Particle Images Velocimetry (PIV) experiment. Down-flow and up-flow ratio, slanted edges and the distance of the baffles to the bottom are analyzed by quantifying the mixing homogeneity and mean residence time. The three-dimensional CFD simulation results of the ABR shows a good agreement compared with the PIV experiment results. At higher wastewater flow rates, homogeneity increases in the reactor; however, the higher velocity at the upflow part of the chamber potentially affects the solid washout. Increasing the ratio of downflow and upflow parts, keeping the distance of baffles close to the bottom, and raising the angle of slanted edge, provides better homogeneity. Designs with a ratio of 1:4, the normalized distance of baffles to the bottom of z/H=0.11, and the slanted edge of 450 showed the best performance amongst the tests.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022920

Year: 2022