new energy conversions using microorganisms and electrodes
TRANSCRIPT
New energy conversions using
microorganisms and electrodes
Annemiek ter Heijne
Sub-department of Environmental Technology
Sep 24, 2015
Wastewater contains energy!
From aerobic to anaerobic wastewater
treatment
Source: http://www.uasb.org
Since 1970/80’s Before 1970/80’s
COD = chemical oxygen demand = measure for organic components in wastewater
A next generation wastewater treatment is
required
Biogas Production
Biogas Treatment (a.o. H2S removal)
Electricity Production (gasmotor)
Electricity
Source: http://www.paques.nl
Efficiency: +/- 30%
# of Units: At least 3
Electrochemically active microorganisms
Microorganisms catalyze the oxidation of
wastewater (acetate) at the bio-anode
CH3COOH + 2 H2O 2 CO2 + 8 H+ + 8 e-
Microbial Fuel Cells convert wastewater
directly into electricity
acetate
CO2
waterbacteria
anode cathode
oxygen
H+
electrons
acetate
CO2
waterbacteria
anode cathode
oxygen
H+
electrons
Cell configurations for bioelectrochemical
systems
Versatility in reactions and applications
MFC
MEC
Microbial Electrolysis Cells for hydrogen
production from wastewater
We need a breakthrough...
Year
... and we need experience with scaling-up
Decreasing internal resistance
Decreasing material cost
Increasing revenues (niche applications)
Capacitive electrodes for bio-anodes
Improved performance with a capacitive
layer
Deeke et al., 2012, ES&T
Capacitive bio-anode
Non-capacitive bio-anode
Acetate CO2 + H+
e-
e-
e-
e-
e- e-
e- e-
K+
K+
NH4+
K+
H+
NH4+ K+
Na+
e-
e- e-
e-
e-
e-
e-
e- e-
e-
e-
e- e-
K+
K+
K+
K+
K+ K+
NH4+
NH4+
H+
H+ H+
H+
H+
Na+ NH4
+
NH4+ e-
NH4+
H+
K+
e- Acetate
CO2 + H+
Acetate
CO2 + H+
Capacitive granules (activated carbon)
500 m2/g
Electro-active biofilm
Activated carbon granules as a basis for a
fluidized bed Microbial Fuel Cell
e-
N2 gas
wastewater
clean water
H+ Charging reactor
Discharge cell
anode
cathode
O2 + H+
H2O
Capacitive Fluidized Bio-anode
Increase in current density with increasing
granule loading: proof of principle
Time (days)
80 100 120 140 160 180 200 220 240
Curr
ent de
nsity (
A/m
2)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
100 g AC
150 g AC
200 g AC
Deeke et al., 2015, ES&T
Measure single granule behaviour under
controlled conditions
1.5 cm
One single granule can produce 0.6 mA:
>1,000x more than achieved in reactor
Understand fundamentals: Capacitance of
electrode influenced by biofilm
GAC PK GG
CV
(F
cm
-3)
0
20
40
60
80
Biotic
Abiotic
GG
0.0
0.5
1.0
1.5
A
Non-capacitive Capacitive
Develop a reactor that can achieve higher
conversion rates (current)
Nitrogen and energy recovery from urine:
high soluble COD and NH4+ concentrations
Value from Urine principle
NH3 recovery BES
Struvite
recovery
Collection
Microorganisms catalyze N and energy
recovery from urine
Acclimation of bio-anodes to urine
Piloting urine treatment (30 persons) at
Wetterskip Fryslan & Wetsus
Proof of principle: copper and electricity
recovery
Ter Heijne et al. ES&T, 2012
Cell configuration with low internal
resistance
Rodenas Motos et al., Front.inMicrobiol., 2015
High-rate microbial fuel cell with copper
Plant Microbial Fuel Cell
New source
24 h/d
Self repairing
No fine dust emissions
Proof-of-principle: plants produce electricity
Strik et al. 2008 Int. Journal Energy Research 32
Power to (bio-)gas
www.electrochaea.com
Biocathodes offer an energy efficient
alternative for power to gas
Methane production rate (m3/m3 per day)
𝜂Coulombic(%) methane
PhaseI 0.2119 59.49
Phase II 0.2875 56.23
Phase III 0.2454 58.31
Phase IV 0.2604 55.35
Continuous and stable methane production
Electricity storage as chemical energy
Acetate production at biocathodes as
alternative to methane
Jourdin et al., J.Mater.Chem.A ,2014
Biobattery for storage of electricity in the
form of acetate: proof of principle
Anode
Cathode
A-
C+
Ac-
O2
H2O
+
+
CO2
Biobattery perspective depends on maximum
acetate concentration
0
50
100
150
200
250
0 0,5 1 1,5 2
Energ
y d
ensity (
Wh/L
)
Acetate concentration (M)
lead-acid battery
(old) li-ion battery
Proof-of-principle
Microorganisms and electrodes offer new
exciting possibilities for energy conversions
Capacitive granules
Urine treatment
Biobattery
Plant MFC
Copper recovery
