Coupling of 3D hydrodynamic and biokinetic growth models for recovery of energy from the wastewater treatment processes

Wastewater treatment processes have high energy-costs and are challenging to optimise due to the complex coupled processes occurring.  In England and Wales over 10 billion litres of sewage are produced every day; taking approximately 6.3 gigawatt hours of energy to treat (1% of the average daily electricity-consumption).  Making use of these waste streams as an energy source is an active area of research. Many of the processes take place within various shape and scale bio-reactors. Within these reactors rheology, rates of mixing, temperature and the relative concentrations of nutrients and bacterial organisms vary over time; these changes have an impact on the rate and performance of the process. There are complex models to account for the biokinetic processes occurring over time; however current models typically assume that these processes take place in homogeneously mixed reactors. This is often not the case and it can provide a significant restriction in the design of new plant.  We have successfully shown in previous work that by coupling realistic flow behaviour with the biokinetic processes occurring (e.g., for the biomass growth and decay behaviour within the reactor), more reliable predictions for growth rates can be obtained; providing potential opportunities to optimise or scale-up a range of processes.  This PhD project aims to develop this coupled modelling framework for processes associated with recovering energy from wastewater (or other similar) processes.