Harnessing free energy - the microbial way

There is an urgent need to make the water industry more sustainable. Currently water companies consume 3% of all electricity produced in the UK. Half of this energy is used for aeration of the activated sludge systems that have served the industry for a century, but are no longer deemed sustainable. Modern bioelectrochemical methods hold great promise as alternative, more sustainable wastewater treatment methods. Avoiding the energy intensive and expensive aeration step these technologies use the internal chemical energy present in the wastewater to produce electricity or biofuels such as hydrogen gas. However, the current generation of bioelectrochemical systems is still in its infancy; the energy recovery of these systems is notoriously inefficient.

My bright IDEA is that a thermodynamic analysis of the various steps inherent to microbial electrolysis and microbial fuel cells has unexpectedly and counterintuitively revealed that the reactions at the anode of these systems are exergonic yet endothermic. This has apparently never been calculated before, but opens up the vista to harvest the energy/heat flow associated with the anodic reaction. The microbial processes occurring at the anode take up heat. The aim of the proposed research is to confirm experimentally that this flow is as significantly as my calculations predict, and then develop a method to harvest this energy. The IDEA is to use thermoelectric materials, semiconductor solids that produce electric current when joined together and subjected to temperature differences across the junction. The concept is not just "bright", the technology that it will spurn has the potential for a step change in the water industry and beyond. In the water industry it may/will be the breakthrough that ushers in a new era of energy efficient bioelectrochemical wastewater treatment methods. Beyond, the concept will open up similar opportunities in other branches of green biotechnology. And further afield, in the chemical industry, the concept to harvest energy from exergonic yet endothermic process steps will have analogous applications. The bright IDEA research proposed here aims to provide the proof of principle for these developments. We will protect the iIDEA with a patent.

The aim of this bright IDEAS project is to provide proof of principle that endothermic reactions at the anode of microbial fuel cells(MFCs) and microbial electrolysis cells (MECs) can be used to harvest energy from the environment. MFCs and MECs are currently being developed for sustainable wastewater treatment and the production of biofuels.

The first industries to be impacted by the proposed research are therefore the water industry and other industries working with green biotechnologies.

Other industries that will be impacted are the chemical industry and the electronics industry.

The chemical industry, because the concepts that apply to bioelectrochemical systems equally apply to many other chemical systems: wherever processes are exergonic yet endothermic the concept is applicable.

The current generation of thermoelectric materials is modestly efficient; when the market for these materials expands, there will be an impetus the serve this market, and an incentive to improve performance. This benefits the electronics industry. This will benefit the economy and society at large.

The UK will benefit from these concepts as local industries will get to use these technologies first.

All these developments will need a strong science and engineering base. The UK has such a base, and is well placed to carry out research and development needed.