Microbial Fuel Cells for Wastewater Treatment - Biotechnologies and Biomimetics for Civil Engineering - page 406

Effluent

e-

e-

Effluent e-

(a)

(b)

Effluent e-

Organic
matter

H +

H +

O 2

AIR

H +

CO 2

H 2 O

H +

H +

Influent Influent

Influent

PEM

PEM

Fig. 18.1 Schematic diagrams of MFCs: a a two-chamber MFC; b a single-chamber MFC with
open air cathode

industrial, and animal wastewater together (Logan 2004 ). Thus, capturing part of
this energy would provide a new source of electrical power and would also
compensate the consumption of energy for wastewater treatment.
Recently, microbial fuel cells (MFCs) (Allen and Bennetto 1993 ; Logan et al.
2006 ; Lovley 2006 ), which are the bioelectrochemical systems, are generally
regarded as a promising and sustainable technology for their direct electrical
power production from wastewaters (Rabaey and Verstraete 2005 ). A conventional
MFC consists of a biological anode and a cathode (Fig. 18.1 a), where exoelec-
trogenic microorganisms could catalyze electrochemical reactions through inter-
action with the electrodes (Logan et al. 2006 ; Rabaey et al. 2007 ; Clauwaert et al.
2008 ). The electrons available through the metabolism of the electron donors by
microorganisms are transferred to the anode and then to the cathode through the
circuit; in the cathode, the oxidant is reduced with the consumption of protons
available through the membrane from the anode (Allen and Bennetto 1993 ).
In terms of potential applications, MFCs and related bioelectrochemical systems
can be utilized for renewable energy generation and wastewater treatment,
i.e., organic matter elimination and nitrogen removal (Logan and Regan 2006b ;
Clauwaert et al. 2007 ; Rozendal et al. 2008 ; Yu et al. 2011 ), for the potential
production of valuable products, such as hydrogen, methane or hydrogen peroxide
(Liu et al. 2005c ; Rozendal et al. 2006 , 2009 ), for bioremediation of recalcitrant
compounds (Catal et al. 2008 ; Morris and Jin 2008 ), for desalination (Forrestal et al.
2012 ; Yuan et al. 2012 ; Feng et al. 2013a ), and as biosensors for on-line monitoring
of treatment processes (Kim et al. 2007b ) and biological oxygen demand or toxic
contaminants in wastewater (Kim et al. 2003 ; Chang et al. 2004 ; Kim et al. 2007b ).