A scalable model of fluid flow, substrate removal and current production in microbial fuel cells

Jordan R Day,Elizabeth S Heidrich,Toby S Wood

doi:10.1016/j.chemosphere.2021.132686

Jordan R Day, Elizabeth S Heidrich + Show 1 more

Open Access

https://doi.org/10.1016/j.chemosphere.2021.132686

Copy DOI

Journal: Chemosphere	Publication Date: Nov 2, 2021
Citations: 8	License type: cc-by

Affiliation: Newcastle University

Abstract

Mathematical modelling can reduce the cost and time required to design complex systems, and is being increasingly used in microbial electrochemical technologies (METs). To be of value such models must be complex enough to reproduce important behaviour of MET, yet simple enough to provide insight into underlying causes of this behaviour. Ideally, models must also be scalable to future industrial applications, rather than limited to describing existing laboratory experiments. We present a scalable model for simulating both fluid flow and bioelectrochemical processes in microbial fuel cells (MFCs), benchmarking against an experimental pilot-scale bioreactor. The model describes substrate transport through a two-dimensional fluid domain, and biofilm growth on anode surfaces. Electron transfer is achieved by an intracellular redox mediator. We find significant spatial variations in both substrate concentration and current density. Simple changes to the reactor layout can greatly improve the overall efficiency, measured in terms of substrate removal and total current generated.

Highlights

The standard activated sludge method of wastewater treatment currently requires 1.3–2.1 kJ/gCOD (Oh et al, 2010), yet wastewater typically contains 16.4 kJ/gCOD of chemical potential energy (Dai et al, 2019)
We briefly review the different approaches that have been taken in previous microbial electrochemical technologies (METs) models
In the results that we have presented above, our goal was to under stand the effects of hydraulic retention times (HRTs) and geometry on reactor efficiency, rather than to reproduce quantitative results from particular lab experiments

Summary

Introduction

The standard activated sludge method of wastewater treatment currently requires 1.3–2.1 kJ/gCOD (Oh et al, 2010), yet wastewater typically contains 16.4 kJ/gCOD of chemical potential energy (Dai et al, 2019). Most modelling efforts have been focused on reproducing experimental results at lab scale (volume < 1 L) (Gadkari et al, 2019; Marcus et al, 2007; Kataky et al, 2020; Lacroix et al, 2021). These models are yet to realise their potential in helping to guide this tech nology towards application

Objectives

Methods

Results

Conclusion