Experimental Multiphase Characterization and Hydrodynamic Dataset of a Multi-Diffuser Fine-Bubble Aeration Reactor

This dataset accompanies the article “Local Multiphase Characterization of Dense Fine-Bubble Aeration Systems: Hydrodynamics, Plume Interaction and Implications for Oxygen Transfer in WWTP-Scale Configurations” (2025). It contains the complete experimental data used to quantify how airflow rate influences mixing, bubble plume interaction, and oxygen transfer efficiency in a pilot-scale aeration tank equipped with a 4 × 4 array of commercial membrane diffusers representative of full-scale WWTP installations. The experiments were performed in a pilot aeration tank reproducing the diffuser density, spacing, and geometry typically found in municipal WWTPs. A total of 16 commercial fine-bubble diffusers (membrane type) were operated under multiple airflow conditions to evaluate the coupled hydrodynamics and oxygen transfer performance of interacting bubble plumes. Airflow rate was systematically varied to assess its effects on both liquid-phase mixing and gas-phase behavior. The study relies on a multi-sensor methodology combining spatially resolved, local two-phase measurements: Dual-tip Conductivity Probe (CP) arrays to determine gas-phase properties, including bubble size distributions, bubble rise velocity, void fraction (ε), and Interfacial Area Concentration (IAC). Acoustic Doppler Velocimetry (ADV) to map three-dimensional liquid-phase velocity fields across the tank. High-speed camera (HSC) imaging to validate bubble size and velocity data through contour-based image analysis. From these measurements, key hydrodynamic and mass transfer parameters were derived, including: Bubble size and rise velocity distributions Gas holdup (ε) Interfacial Area Concentration (IAC) Local and sectional liquid-phase circulation patterns Standard Oxygen Transfer Efficiency (SOTE) The dataset is organized as follows: First CSV: figures_data_REACT-UJI.xlsx – contains all numerical data corresponding to the figures presented in the article. This includes the mean values of Interfacial Area Concentration (IAC), gas holdup, bubble size, and bubble velocity, as well as their vertical variation within the tank. It also includes oxygen transfer–related metrics used to generate the plotted trends and comparisons in the manuscript. Second CSV: profiles_REACT-UJI.xlsx – includes the complete set of local measured and derived parameters for all airflow conditions. This file provides the radial distributions of bubble size, bubble rise velocity, void fraction, Interfacial Area Concentration (IAC), and liquid-phase velocity obtained from the multi-sensor measurements. These radial profiles form the basis for analysing plume structure, diffuser interaction, and hydrodynamic zoning within the aeration tank. These datasets enable users to reproduce the hydrodynamic zoning, validate mechanistic models of plume interaction, evaluate diffuser-array effects on mass transfer, and develop or benchmark predictive models for fine-bubble aeration systems operating under WWTP-relevant conditions. They provide a physically consistent reference for the characterization of dense diffuser layouts, where plume interaction governs mixing, bubble residence time, and ultimately oxygen transfer efficiency.