Process intensification towards sustainable wastewater treatment with phototropic biofilms

ongoing

Improving current biological wastewater treatment (WWT) plants towards more sustainable solutions is a priority of the EU (Water Framework Directive). Conventional activated sludge technology faces some challenges such as high O2 demand and inevitable CO2 emissions. Phototropic microorganisms offer a sustainable way of WWT by converting CO2 to O2 and valuable biofeedstock which can further be converted to bioenergy. Photogranules are compact spherical biofilms which contain high amounts of phototrophs in addition to heterotrophs. As a result, photogranule based WWT can couple CO2 and O2 fluxes from different microorganisms leading to an aeration free WWT. However, to utilize the true potential of this technology, revolutionary reactor designs together with more fundamental understanding on photogranulanation is needed. This work aims to intensify photobioreactors for WWT by using a multidisciplinary approach which combines microrhelogy and microbiology with mass and photon transport models. To have more control over growth and light, novel supports for biofilms will be designed. In addition, the project will explore the relationship between environmental conditions such as light availability and shear on microbial community composition and structure in complex phototropic biofilms by both microfluidic experiments and mathematical models. The information obtained from these studies will be translated to a macroscopic level using simplified transport phenomena models to design an efficient photobioreactor. The findings of this study will both advance our understanding of phototropic biofilms and pave the way towards industrial-scale sustainable WWT. With this project, I am aiming to combine my background on design and modelling of light-driven multiphase systems with the distinguished expertise of the host research group in WWT at TU Delft while acquiring further knowledge on mass transfer in photobiofilms during my secondment at ETH Zurich.