(208e) CFD Modeling of Waste Water Bio-Reactors

Computational Fluid Dynamic (CFD) modeling is a powerful tool for equipment design and development and is widely used at UOP, particularly for the multiphase systems. One such system is UOP’s XCeed^TM Bioreactor technology. Through CFD modeling, the hydrodynamic interaction of the air and water in the fixed-bed bioreactor was studied and the results were used to design a new large-scale wastewater treatment bioreactor. An innovative and efficient modelling method was developed to overcome a complex bioreactor configuration.

The XCeed^TM bioreactor packing media has a proprietary solid phase which uniquely distributes high surface area within highly porous void spaces.

The critical challenge in this three-phase CFD model was finding an accurate approach to mimic wastewater (hydraulic) and aeration (gas-bubbles) patterns through the solid phase containing substantial biomass.

To better understand the flow pattern, flow distribution and the air bubble residence time inside the XCeed^TM Bioreactor, the analysis was broken down into two sub-models.

Part 1 single-phase water-flow only analysis showed that the XCeed^TM packing media caused the water flow to distribute uniformly across the packed-bed, even when high levels of biomass are present, without any channeling or by-pass or plugging.

Part 2 two-phase air/water flow analysis showed that the XCeed packing void areas affected immediate air flow expansion into and subsequent distribution throughout the high surface area of the packed bed, even with the accumulation of high biomass.

These CFD results confirm the effective benefits of UOP’s distinctive approach to blending surface area with open space to enhance air/water distribution without plugging or channeling even when high biomass solids are present.