Modelling the influence of soil properties on performance and bioremediation ability of a pile of soil microbial fuel cells

Highlights: • Novel low-cost tubular SMFC and arrangement in piles of multiple SMFC units. • The innovative modular design allows treatment at customised soil depths. • First mathematical model for soil microbial fuel cells. • The model predicts the performance of the SMFCs pile according to soil properties. • The model guides on the design of arrays of SMFCs piles to effectively treat a contaminated area. -- Abstract: Worldwide, intense industrial and agricultural activities pose serious issues of land contamination. Soil microbial fuel cells (SMFCs) have great potential as a low-cost, and self-powered solution to soil bioremediation, compatible with operations in remote areas. In this study, we propose a novel tubular SMFC design, in which a ceramic tube acts as the separator between the air-cathode and the anode, while providing structural support. No oxygen reduction reaction catalyst is used, and to reach depth, several SMFC units are piled together. To assess the effect of both the system design and soil properties on performance, a mathematical model, calibrated with experimental data, is proposed, which accounts for chemical and (bio)electrochemical reactions, as well as for charge conservation and transport phenomena. The information generated provides useful indications on optimal design and operational conditions for SMFCs and a guide to effective scale-up strategies for their use in bioremediation.