10.1021/acs.est.7b00174.s001
Dongwon Ki
Dongwon
Ki
Sudeep C. Popat
Sudeep C.
Popat
Bruce E. Rittmann
Bruce E.
Rittmann
César I. Torres
César I.
Torres
H<sub>2</sub>O<sub>2</sub> Production in Microbial
Electrochemical Cells Fed with Primary Sludge
American Chemical Society
2017
anode suspension
hydrogen peroxide
Microbial Electrochemical Cells Fed
carbonate ions
anode side
retention time
anode biofilm
MPPC
anodic performance
H 2 O 2 diffusion
PS
Coulombic efficiency
methane production
batch cathode operation
H 2
chemical oxygen demand removal
electrolysis cell
energy requirement
9 day
H 2 O 2 production
MEC
h 2 O 2 Production
H 2 O 2
Primary Sludge
H 2 O 2 concentration
energy-conversion technology
6 h
2017-05-09 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/H_sub_2_sub_O_sub_2_sub_Production_in_Microbial_Electrochemical_Cells_Fed_with_Primary_Sludge/5011997
We
developed an energy-efficient, flat-plate, dual-chambered microbial
peroxide producing cell (MPPC) as an anaerobic energy-conversion technology
for converting primary sludge (PS) at the anode and producing hydrogen
peroxide (H<sub>2</sub>O<sub>2</sub>) at the cathode. We operated
the MPPC with a 9 day hydraulic retention time in the anode. A maximum
H<sub>2</sub>O<sub>2</sub> concentration of ∼230 mg/L was achieved
in 6 h of batch cathode operation. This is the first demonstration
of H<sub>2</sub>O<sub>2</sub> production using PS in an MPPC, and
the energy requirement for H<sub>2</sub>O<sub>2</sub> production was
low (∼0.87 kWh/kg H<sub>2</sub>O<sub>2</sub>) compared to previous
studies using real wastewaters. The H<sub>2</sub>O<sub>2</sub> gradually
decayed with time due to the diffusion of H<sub>2</sub>O<sub>2</sub>-scavenging carbonate ions from the anode. We compared the anodic
performance with a H<sub>2</sub>-producing microbial electrolysis
cell (MEC). Both cells (MEC and MPPC) achieved ∼30% Coulombic
recovery. While similar microbial communities were present in the
anode suspension and anode biofilm for the two operating modes, aerobic
bacteria were significant only on the side of the anode facing the
membrane in the MPPC. Coupled with a lack of methane production in
the MPPC, the presence of aerobic bacteria suggests that H<sub>2</sub>O<sub>2</sub> diffusion to the anode side caused inhibition of methanogens,
which led to the decrease in chemical oxygen demand removal. Thus,
the Coulombic efficiency was ∼16% higher in the MPPC than in
the MEC (64% versus 48%, respectively).