Finding low-cost, highly efficient materials

Many of the considerations for choosing materials and deciding on the appropriate MFC architecture are those that apply to any biofilm (fixed bacterial film) bioreactor, and so it is useful to consider briefly here differences and similarities between MFCs and biofilm reactors used for wastewater treatment (WWT). Experience with trickling filter (TF) biofilm reactors, where wastewater flows by gravity over a support material (rocks, random plastic media, or structured plastic media), has resulted in typical engineering specifications for specific surface areas of 100 m of surface area per cubic meter of reactor (100 m /m ) for structured plastic media. Higher specific surface areas are used in 

Microbial Fuel Cells. By Bruce E. Logan Copyright 2008 John Wiley Sons, Inc. 

We can see from this brief comparison that we can expect similarities but also differences in choosing MFC materials and architectures. The different materials, with their respective advantages and disadvantages, are the focus of this chapter. The issue of organizing these materials into architectures, in ways that maximize power and confer an acceptable structure, is addressed in the next chapter. 

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