Environmental Engineering Reference
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Floating
sensor
Underwater
sensor
Ground
sensor
Sensors
O
2
+4e
-
+4H
+
4H
2
O
+
Cathode
1~10 cm
Water
H
+
1~10 cm
Anode
e-
e-
-
Vcathode-Vanode~0.75 V Open Circuit Potential
Desulfo.
D. Aceto.
S
2-
S
S, H
+
SO
4
2-
Organic
matter
CO
2
, H
+
Sediment
Fig. 18.5 Schematic representation of fundamental principle of the mediator less sediment
MFCs used to provide energy for on-site sensors. Microorganisms colonizing the anode are most
similar to Desulfuromonas acetoxidans (D. Aceto.), which could oxidize acetate in sediment and
transfer
electrons
to
the
anode.
Desulfo.
represents
the
species
in
the
Desulfobulbus
or
Desulfucapsa genera, which could oxidize anode generated S
0
to SO
4
2-
surface water or marine sediment and cathode is placed in the water above the
sediment (Tender et al.
2002
; Logan and Regan
2006b
; Rezaei et al.
2007
). The
sedimentary organic carbon (Aller
1994
) or sulfate compounds (Rabaey et al.
2006
) present in the sediment are oxidized by microorganisms growing on the
anode surface for production of electricity. There are several attempts to dem-
onstrate the availability of sediment MFCs as power source for underwater
(Donovan et al.
2013
), ground (Donovan et al.
2008
), and floating sensors (Nielsen
et al.
2007
; Tender et al.
2008
; Donovan et al.
2011
). The first demonstration of
scale-up of MFC was used to power a weather buoy embedded with temperature
and humidity sensors using two sediment MFCs that generated 24 mW and
36 mW (Tender et al.
2008
). The sediment MFCs were deployed in the Potomac
River, at Washington, DC and Tukerton, NJ, USA. Donovan et al. used sediment
MFCs to operate a low-power (11 mW) and a high-power (2500 mW) wireless
temperature sensors in a creek at Palouse, WA, USA. (Donovan et al.
2008
;
2011
).
The average power generation to power a remote device via a sediment MFC
ranges from 3.4 to 36 mW (Dewan et al.
2014
). These studies illustrate that MFCs
deployed in natural aquatic environment (i.e., rivers, lakes, or oceans) can produce
enough energy to operate sensors requiring low power.
However, MFCs for wastewater treatment have faced a variety of restrictions in
terms of practical implementation. First, the real wastewater contains complex
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