Improved reactor design and operation for the anaerobic digestion of biowastes

Anaerobic digestion is usually carried out in single semi-continuous reactors, especially due to their simpler construction and operation. However, this simplicity implies relatively low conversion rates and productivities and, as a consequence, larger digester volumes are needed.

This PhD project will look at possible strategies to develop a new generation of digesters, which can perform a faster and more compact conversion of biowastes. There are different approaches that will need to be explored and evaluated, which may modify both the design and the operation of the digester. Some examples are: biomimicry, model-based design of reactors, microaerobic conditions, staged and temperature phased digesters, use of activated or degradable carriers. The outcome of this first part of the project will be a set of design and operational recommendations that will be experimentally tested in a laboratory environment. A prototype will need to be built and its performance will be compared to existing CSTR reactors.

The focus of the study will be on micro and small-scale digestion, where process intensification would result in comparatively high advantages. In this regard, the project benefits from existing collaborations with industrial partners and project developers, which can contribute both to the design phase and potential scale-up considerations.