Research Projects

The shift towards renewable energy sources is the global focus. Producing renewable energy through anaerobic digestion (AD) to produce CH4, bio-H2 or other products is a popular choice. The AD process, however suffers critical process set-back owing to the intricate balance that has to be maintained between microbial activity and the inorganic ionic equilibria, pH among other operational parameters. This project builds on combining the effect of biochar addition and regulation of oxidation-reduction potential (ORP) in an electro-fermentation (EF) setup for enhancing the CH4 yield in AD. The research hypothesis in this work is that the application of biochar with a targeted regulation of ORP, can promote an anaerobically active microbiome which can enhance the CH4 recovery from the bio-reactor. The hypothesis is further expanded to state that such anaerobically active biomass can withstand higher pH variations and can be used as a seed for future AD reactors. As elaborated in the state-of-the-art discussion part, the effect of biochar addition has been through empirical approach in different AD reactors. Majorly, biochar-microbe interaction is not fully explored in such setups. Similarly, the EF setups in past are operated from an electrochemical reactor perspective without giving due importance to the material-microbe interactions inside the reactor. It would thus be interesting to understand the synergistic effect of both in enhancing biomethane yield. The scope of research in this work includes two stages. In the first stage, experiments will be conducted to understand the electronic interaction between biochar and microbes with biochar as a working electrode in an EF setup. The prime objective is to test the hypothesis that such biochar electrode-based EF should tackle both the pH related issues owing to biochar’s buffering capacity, as well as reduce the dependency on diffusion limited electron transfers (ET) through ORP regulation. In the second stage of the project, the ET mechanism from the cell surface to the conductive surface of biochar will be modelled by quantum modelling approach. Prediction and validation of the ET pathway will be tested by estimating the energetics involved with the electron tunnelling effect and by examining the role of different biochar surface functional groups in ET process. The overall outcome from this second stage is understanding the molecular level contribution of biochar to interspecies electron transfer. The research proposed will investigate the fundamental ET pathways and will try to identify the functional groups on biochar surface which encourage the ET between the cell membrane and the biochar surface. This will help in designing biochar production experiments to promote such ET favoring surface functional groups. In addition to this achievement of understanding the ET mechanism at a molecular level, the proposed technology for enhancing AD can also be replicated for renewable energy generation.