Effect of Gas Flow Rate on Hydrodynamics and Dissolved Oxygen Characteristics in a FineBubble Aeration System: A CFD-Based Study

Niesa Hanum Mistoro; Mohamad  Iqbal Firmansyah; Andik Yulianto; Ninda Anggita Sari; Henny Sudibyo; Wahdan Achmad Syachuddin

doi:10.33005/envirotek.v18i1.2343

Authors

Niesa Hanum Mistoro Department of Environmental Engineering, Faculty of Civil Engineering and Planning, Universitas Islam Indonesia
Mohamad Iqbal Firmansyah Tensor Karya Nusantara Company - Pundong II, RT 04/RW 05, Tirtoadi, Mlati, Sleman, Yogyakarta, Indonesia
Andik Yulianto Department of Environmental Engineering, Faculty of Civil Engineering and Planning, Universitas Islam Indonesia
Ninda Anggita Sari Magister Program of Environmental Engineering, Faculty of Civil Engineering and Planning, Universitas Islam Indonesia
Henny Sudibyo Research Centre For Energy Conversion Technology, National Research and Innovation Agency of Indonesia (BRIN)
Wahdan Achmad Syachuddin Department of Ecology, Environment and Geoscience, Umeå University, Umeå S-901 87, Sweden

DOI:

https://doi.org/10.33005/envirotek.v18i1.2343

Abstract

This study evaluates the effect of gas flow rate on hydrodynamic behavior and dissolved
oxygen (DO) profiles in a lab-scale fine-bubble aeration system using computational fluid
dynamics (CFD). Triplicate experiments were conducted in a 17.06 L batch reactor containing
domestic wastewater, with a disk aerator operated at gas flow rates of 0.5, 1.0, and 1.5 L/min.
CFD was applied to interpret internal flow behavior through velocity contours and streamline
patterns. The results showed that DO increased significantly with higher gas flow rates (p <
0.05), with 1.5 L/min achieving the highest final DO of 6.73 ± 0.12 mg/L. CFD analysis
indicated that higher gas flow rates produced more developed circulation patterns, although
the area-weighted average velocity magnitude on the selected plane decreased from 0.0317
m/s at 0.5 L/min to 0.0203 m/s at 1.5 L/min. These findings suggest that oxygenation
improvement was governed not only by mean liquid velocity, but also by gas input and internal
flow organization. This study uniquely integrates experimental DO measurements with CFDpredicted hydrodynamic behavior in a laboratory-scale domestic wastewater aeration system.