energy is retrieved from bacteria feeding of an organic substrate in
anaerobic conditions. A review of the literature published since 1994 on
microbial and enzymatic biofuel cells is provided in Ref. [6]. The
increasing interest of electroactive microorganisms applications by
means of bioelectrochemical systems is discussed in Ref. [7] presenting
the performance of different types of MFCs. The detailed operation of
MFC and the conversion of organic wastes into energy is documented in
Refs. [8,9]. Additionally, structural information about MFCs’ materials
and several examples of application can be found in Ref. [10]. A standard design of a single chamber air-cathode MFC is presented in Fig. 1,
along with the equations describing the involved reactions for an
acetate-based substrate.
MFCs can be used wherever a liquid organic source for carbon is
available, provided the source is not toxic and the environment
adequate for the bacteria. As such, MFCs can be applied to wastewater
treatment plants, either for industrial, sewage or agriculture wastewater, being useful for powering ultra-low power (ULP) and low power
(LP) sensors, as shown in Fig. 2.
In order to accurately predict if the power profile of an MFC can fit
the energy needs of the aforementioned sensors, both in magnitude and
in time, an electrical model of the MFC is paramount. The maximum
voltage level that can be produced by any fuel cell corresponds to its
electromotive force, or Eemf , derived with the Nernst equation: