Optimising anaerobic co-digestion: improving the outputs and stability of anaerobic processes

Anaerobic co-digestion consists of the anaerobic digestion (AD) of a mixture of two or more substrates with complementary characteristics, so that biogas production, digestate characteristics and process stability are enhanced through their joint treatment. The Energy 2050 group is researching co-digestion for different scenarios, such as the digestion of energy-rich substrates to boost biogas productions in demand driven applications, or to improve the degradation of agricultural by-crops in rural digesters in developing countries.

This PhD project will systematically research the possible synergistic effects of co-digestion. These include the enhancement of organic matter decomposition due to the addition of easily degradable substrates (priming effect), the increased buffering capacity, the reduction of inhibitory causes, the provision of balanced micro and macro nutrients, the role of fibers as carriers of micro-organisms, the provision of optimal water content, etc. Modelling will be used to describe mechanistic interactions and design co-digestion strategies in different scenarios, which will be tested and validated with laboratory scale reactors.