Mathematical analysis of bioelectrochemical systems

Lead Research Organisation: University of Surrey
Department Name: Chemical Engineering

Abstract

Significant amount of energy and billions of pounds are spent every year in UK to treat the industrial/domestic/municipal wastewater. However, this wastewater which typically contains a lot of organic compounds can actually be used as a valuable resource in devices known as bioelectrochemical systems (BESs). BES are like any other electrochemical cell (e.g. battery) and consist of an anode, cathode and a separating membrane (optional), but the difference lies in how the electrochemical reaction is catalysed. In BES, at least one or both of the electrode reactions are catalysed with the help of microorganisms. By combining living biological systems with electrochemistry, BES makes it possible to utilize the chemical energy from wastewater and generate electricity (microbial fuel cells, MFCs), hydrogen (microbial electrolysis cells, MECs) or value-added chemicals (microbial electrosynthesis, MES).
Among different BESs, a microbial electrosynthesis (MES) system in which both electrodes are biocatalysed, makes it possible to convert wastewater (fed at the bio-anode) and waste CO2 (fed at the bio-cathode) into useful multi-carbon compounds that are precursors to commodity chemicals and transportation fuels. Such MES systems are thus of particular interest in the context of both wastewater treatment as well as CO2 capture and utilization. The electrochemical reaction in MES is however non-spontaneous and requires external energy. Renewable energy sources (solar, wind) can be used to supply the required power. Thus MES also offers a novel way to store the renewable electrical energy in the chemical bonds of organic compounds that can be stored and transported more easily.
MES system performance depends on a number of biological, physical-chemical and electrochemical parameters. Following the first experimental demonstration in 2009-2010, a variety of studies have been conducted to investigate the effect of operational parameters on MES performance. These investigations have helped in improving the product yields however further improvements in performance require a deeper understanding of the mechanisms governing the process.
Past research on MES has extensively focused on experimental studies, while mathematical modelling has remain neglected. The development of mathematical models will be critical to the optimization and scaling of MES systems in future. At present, there are no mathematical models available to predict the overall performance of the MES process. In this project I propose to develop comprehensive mathematical models that can not only provide insight on the governing mechanisms of MES but also on how MES systems will affect the environment. Such numerical models will compliment experiments and help to develop this technology towards commercialisation at a reduced cost and time.
Development of efficient MES systems that use low-grade substrates such as wastewater and waste CO2 for chemical production provide a new technology platform for sustainable bioproduction and wastewater treatment. Such systems can help tackle environment and energy challenges in an integrated approach. Bioproduction of chemicals by consuming CO2 will also reduce the dependency on fossil fuel based carbon sources currently used in chemical industries and can assist the UK in achieving its climate targets. Thus in addition to the economic and ecological benefits, research on MES is also of major societal importance.
Though the proposed research is focused on MES systems, the insight obtained from these models will also be applicable for analogous bioelectrochemical systems such as microbial fuel cells and microbial electrolysis cells. Thus the research outcomes will contribute directly towards popularizing such sustainable technologies for bioproduction of wide range of chemicals (MES, MEC) as well as generation of renewable electricity (MFC) from wastewater.

Publications

10 25 50
 
Description A microbial fuel cell (MFC) is a biological fuel cell that helps convert chemical energy of wastewater into electricity with the help of bacteria. I have developed a fast converging dynamic model for MFCs which is easy to implement and is computationally inexpensive, and can thus serve as a good starting point to determine the operating conditions for fairly optimum system performance, before more comprehensive experimental/numerical studies are performed.
Exploitation Route Integration of the dynamic simulation results with techno-economic and life cycle analysis can provide a holistic understanding of the overall sustainability of MFCs.
Sectors Energy,Environment

 
Description MES experiments for model validation 
Organisation Indian Institute of Chemical Technology, Hyderabad
Country India 
Sector Academic/University 
PI Contribution Computational model for microbial electrosynthesis systems
Collaborator Contribution Provided the experimental data for model validation and parameter estimation.
Impact We have submitted a manuscript of this work to Physical Chemistry, Chemical Physics journal.
Start Year 2018
 
Description MFC work with Newcastle University 
Organisation Newcastle University
Department School of Chemical Engineering and Advanced Materials
Country United Kingdom 
Sector Academic/University 
PI Contribution Dynamic simulation models of MFC which will be validated using the experimental results from Newcastle University.
Collaborator Contribution After an initial visit to the research lab of Dr. Eileen Yu at Newcastle University, we are actively collaborating on Microbial fuel cell studies. Jean-Marie, Research fellow from Dr. Eileen Yu's lab is running the experiments on MFC
Impact Currently working on finishing a work on a manuscript on the collaborative work, and we hope to submit it by February 2019. The collaboration combines the strength of the research groups in the two universities.. At Surrey we are mainly focussed on development of theoretical models, while Newcastle is involved in experimentation on Microbial fuel cells.
Start Year 2018
 
Description International Society for Microbial Electrochemistry and Technology (ISMET)-EU Conference (Newcastle) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This involved a poster and oral presentation. I was able to showcase and discuss my research with over 100 academics working on microbial electrochemical technologies.
Year(s) Of Engagement Activity 2018
 
Description Waste to Wealth workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact I co-organised the UKRI funded Waste to Wealth (W2W) workshops held on 11 March in Swindon. The workshop was conducted in an interactive manner to engage
researchers and relevant industry professionals to map out the market size and needs for resource recovery from waste (RRfW) systems.

The output from the workshop is being synthesised into policy and strategy papers to present to industries and inform policy makers.
Year(s) Of Engagement Activity 2019