A	Surface area of the electrode
ACS	Actual charge due to the substrate
AEM	Anion exchange membrane
AMD	Acid mine drainage
bCOD	Number of electrons exchanged per mole of oxygen
BPM	Bipolar membranes
CEM	Cation exchange membrane
CI	Current interruption
CM	Ceramic membrane
COD	Chemical oxygen demand
CODf	Final chemical oxygen demand
CODi	Initial chemical oxygen demand
DC-MFC	Dual-chamber microbial fuel cell
DO2	Oxygen diffusion coefficient
EMFC	Voltage generated by the microbial fuel cell
F	Faraday’s constant
FCs	Fuel cells
I	Current
IEC	Ion-exchange capacity
IEM	Ion-exchange membrane
IMFC	Electrical current of the microbial fuel cell
KO	Oxygen mass transfer coefficient
L	Membrane thickness
MCOD	Molecular weight of oxygen
MFC	Microbial fuel cells
MFM	Microfiltration filtration membrane
MWW	Municipal wastewater
NF-117	Nafion® 117
OD	Oxygen diffusion
OR	Ohmic resistance
ORR	Oxygen reduction reaction
P	Power density
PC	Proton conductivity
PEM	Proton-exchange membrane
PEMFC	Proton-exchange membrane fuel cell
PFSA	Perfluorinated sulfonic acid
PMFC	Power generated by the microbial fuel cell
PTFE	Polytetrafluoroethylene
R	Membrane resistance
Rint	Total internal resistance of the microbial fuel cell
SC-MFC	Single chamber microbial fuel cell
SPEEK	Sulphonated polyether ether ketone membrane
TCS	Theoretical charge due to the substrate
UFM	Ultrafiltration membrane
V	Volume of liquid in the anode compartment
WW	Wastewater
ηcoul	Coulombic efficiency
ηCOD	Chemical oxygen demand removal efficiency
ΔV	Voltage difference
ρ	Resistivity