Professor John Bridgeman

Research

Computational modelling

Research in this area began with the development of computational fluid dynamics (CFD) models of flocculation in water treatment to assess floc strength. This challenging, multidisciplinary area of research requires an understanding of the complex interactions between physical, chemical and microbiological processes. The work has generated significant impact; outputs have been used in industry to reduce energy input at treatment sites by up to 66%.

Subsequent research uses both finite volume CFD and lattice Boltzmann modelling (LBM) to address multiphase modelling of non-Newtonian fluids in anaerobic digesters in order to optimize biogas recovery and renewable energy generation for agricultural, waste and water industries (EPSRC Grant EP/R01485X/1). Work has also involved the use of CFD to analyse air blower performance in multiphase activated sludge plant modelling at wastewater treatment works with a view to reducing the carbon footprint of operation.

I have undertaken work modelling leakage from buried pipes. This work employed, for the first time, coupled CFD/discrete element models (DEM) and coupled LBM/DEM to solve the complex fluid flow processes. Outputs are being disseminated within the water industry and discussions ongoing as to how they will be used to identify locations at risk of burst and leakage, so that networks are proactively managed in order to minimize leakage and energy used in pumping.

Simulation work has also incorporated water resource planning, using probabilistic weather generator information to determine the range of potential impacts on hydrology within waterstressed catchments over various time horizons, to assess the probabilities of water shortage as a result of these changes, and to quantify robust policies available to resource managers. Further work has developed simulation tools to minimise cost and energy consumption of water treatment according to raw water input (including climate change scenarios), performance, and risk, using a partially dynamic model, genetic algorithm and Monte Carlo simulation. Thus, there is a strong synergy in my research between changing environmental conditions and the engineering responses required to minimise negative impacts.

I undertake work in river hydraulics to examine the effects of turbulent flow on shear stress distributions in channels, combining physical and numerical modelling with extensive fieldwork measurements. I have undertaken collaborations with colleagues in the School of Geography, Earth and Environmental Sciences at the University of Birmingham on two NERC-funded projects. The first (NERC NE/K012819/1) developed a quantitative numerical representation of micro-scale hydraulic response to biofilm forcing by using pioneering new experimental and numerical approaches, including novel particle image velocimetry and 3-d modelling using a specially modified CFD model developed to account for the dynamic nature of the biofilms. The second project (NERC NE/L003872/1) examined the potential of in-stream Large Woody Debris (LWD) for enhancing the nutrient (nitrogen and carbon) attenuating potential of UK lowland rivers. Specifically, my work developed CFD and state of the art lattice Boltzmann models to analyse the impacts of LWD on hyporheic cycling, residence time distributions and nutrient turnover.

My expertise in the field of computational modelling was recognized via invitations to give keynote addresses at the 13th International Conference on Civil, Structural and Environmental Engineering Computing, Chania, Crete, 2011 and at the IWA Particle Separation Conference, Toulouse, France, 2007, and an invitation to provide a book chapter in 2011.

Water and wastewater management

Here, work has focused on natural organic matter (NOM) in water sources and the subsequent formation of disinfection by-products (DBP) during treatment. The approach has been to further understanding of NOM character in water, to develop relationships between character, reactivity and treatability, and to apply those relationships in innovative ways for maximum impact. I have led a multidisciplinary research team of PhD students and PDRFs, and the outputs have been extensive and strong. Pioneering work has been undertaken on data analysis and mining, using artificial neural networks, parallel factor analysis, and self-organising maps.

Included in this work is the development and evaluation of innovative fluorescence spectrophotometric instruments and techniques for use as real-time water quality sensors, making them suitable for real-time water quality assessment and for process control at water and wastewater treatment works (EU FP7 Incoming European Fellowship PIEF-GA-2012-329962 Fluoro-BOOST), EPSRC Grants EP/H003061/1 and EP/I001379/1). This work also has direct impact on humanitarian aid efforts as a tool for determining water quality in areas of poor sanitation, such as refugee camps and informal settlements. Knowledge transfer is being maximised via the use of EPSRC Impact Acceleration funds and novel instrumentation is now being manufactured at the University of Birmingham. Outputs from this high impact work have been featured on national television (BBC, Bang Goes The Theory) and in the print and digital media.