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 Before 1970/80’s Since 1970/80’s COD = chemical oxygen demand = measure for organic components in wastewater Source: http://www.uasb.org A next generation wastewater treatment is required Biogas Production Biogas Treatment (a.o. H2S removal) Electricity Production (gasmotor) Electricity Efficiency: # of Units: +/- 30% At least 3 Source: http://www.paques.nl 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 electrons CO2 oxygen H+ acetate bacteria anode water cathode 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 Capacitive bio-anode Non-capacitive bio-anode Deeke et al., 2012, ES&T Activated carbon granules as a basis for a fluidized bed Microbial Fuel Cell CO2 + H+ Acetate Na+ eH+ e- H+ e- Capacitive granules (activated carbon) 500 m2/g K+ eee- K+ K+ e- NH4+ K+ K+ e H+ NH4+ eAcetate H+ K+ e- NH4+ e- NH4+ CO2 + H+ Na+ eK+ K+ ee- Acetate K+ e- + e- NH4 e- H+ K+ e eNH4+ H+ ee- NH4+ eH+ K+ e CO2 + H+ Electro-active biofilm Capacitive Fluidized Bio-anode clean water e- O2 + H+ Charging reactor H+ anode H2O cathode Discharge cell N2 gas waste water Increase in current density with increasing granule loading: proof of principle 1.4 100 g AC 150 g AC 200 g AC Current density (A/m2) 1.2 1.0 0.8 0.6 0.4 0.2 0.0 80 100 120 140 160 180 200 220 240 Time (days) 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 80 A Biotic Abiotic CV (F cm-3) 60 1.5 40 1.0 0.5 20 0.0 GG 0 GAC Capacitive PK GG Non-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 Collection Struvite recovery BES NH3 recovery 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 Continuous and stable methane production Methane production rate (m3/m3 per day) 𝜂 Coulombic(%) methane PhaseI 0.2119 59.49 Phase II 0.2875 56.23 Phase III 0.2454 58.31 Phase IV 0.2604 55.35 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 Ac- CO2 O2 + A n o d e C+ A- C a t h o d e + H2O Biobattery perspective depends on maximum acetate concentration Energy density (Wh/L) 250 (old) li-ion battery 200 150 100 lead-acid battery 50 Proof-ofprinciple 0 0 0,5 1 1,5 Acetate concentration (M) 2 Microorganisms and electrodes offer new exciting possibilities for energy conversions Urine treatment Capacitive granules Plant MFC Copper recovery Biobattery Thank you for your attention [email protected]
© Copyright 2026 Paperzz