University of Bath

New Microbubble Method for Dissolved Air Flotation

This project investigate the effectiveness of a new method of microbubble production for Dissolved Air Flotation (DAF) in water treatment.

The main aim of this PhD project is to investigate the effectiveness of a new method of microbubble production using a dissolution type microbubble generator for Dissolved Air Flotation (DAF) in water treatment. The hope is that the new method will enhance the energy efficiency of the separation process. The project consists of both experimental and modelling work. With the modelling work focussed on the hydrodynamics of the existing and improved DAF processes as well as the reaction and mass transfer characteristics. The project could also include an assessment of the scale up and implementation of the new method in existing treatment facilities.

Project outline

Computational modelling

  • Use computational fluid dynamics (CFD) modelling to elucidate the hydrodynamics of existing and improved DAF systems

  • Couple CFD and MATLAB to solve the reaction and mass transfer characteristics

  • Use CFD modelling to assess and select the most appropriate operating conditions (e.g. gas and liquid flow rates) for solid separations

  • USE CFD results to inter- and extrapolate the separation performance

Experimental Work

  • Characterisation of bubbles, visualisation of flow paths, gas transfers etc.

  • Lab scale DAF experiments to verify the computational work.

  • Investigate the removal of different types of contaminants/pathogens.

Science

Three phase modelling of DAF is an area which hasn’t been explored extensively by researchers. Therefore the modelling of the interaction at the gas/liquid/solid interface is an area that will be further explored as part of this research. This presents an opportunity to provide new insights into DAF via the proposed project. The project could also include an investigation into the effects of different pollutants on the effectiveness if the old and new DAF process.

Impact

If the project demonstrates an improved DAF effectiveness with the new microbubble method then it could serve as impetus for existing water treatment facilities to be upgraded and aid in the implementation of the new microbubble method. Through the modelling and experimental work the project should also provide new insights into the existing DAF process.

This is the PhD project of Bert Swart from the Department of Chemical Engineering. The project is supervised by Dr John Chew and Dr Jannis Wenk.