Biohydrogen production from Solid Phase-Microbial Fuel Cell (SP-MFC) spent substrate: apreliminary study.

Dr.Rosa Anna NastroLaboratory for Energy and the EnvironmentDepartment of EngineeringUniversity “Parthenope” of Naples - Italy

Microbial catalysis: exoelectrogenic bacteria

AN INTRODUCTION TO BIOELECTROCHEMICAL SYSTEMS (BESs)

Mn(IV), Fe(III)

Nanowires

Shuttles

+

Biocatalysis

…

Bacteria exchange electrons with the anode in anoxic/anaerobiotic environment

Electrons are transferred from cathode to oxygen

Electrons flow through an external circuit

Protons pass through a cationic permeable membrane

Fuel: organic compounds

Fig.1: Model of a two-chamber MFC.

MICROBIAL FUEL CELLS (MFCs): PRINCIPLES AND APPLICATIONS

Carbon neutral

No chemical catalysts

Bulk liquid model

Environmental temperature

Organic Solid Waste (OSW) : MFCs?

� Municipal wastewaters

� Industrial wastewaters

� Landfill leachate

� Urine

� Polluted soils

� Composite food waste

Organic Fraction of Municipal Solid Waste (OFMSW)

n About 70% of Municipal Solid Waste

n High moisture content

n Bad smell

Anaerobic digestionEnergy input (T=35°C/55°C)

CH4 and CO2 production

Composting treatment

(aerobic metabolism)

Aeration (energy input)

Soil conditioner

ANAEROBIC DIGESTION

BIOHYDROGEN PRODUCTION

RESEARCH QUESTIONS

Can we combine electrogenesis with dark fermentation and anaerobic digestion of solid organic residues?

With what performance?

Anaerobic Digestion or Dark Fermentation ?

Solid phase Microbial Fuel Cells set-up (SMFCs)

SMFCn Single-chambern Air-cathoden Membranelessn Graphite-based electrodes

(AXF-5Q, POCO Graphite Inc., Texas, USA) 67cm2 surface area

OFMSW:§ 78% vegetables§ 13% fruits§ 5% bread§ 3% egg shells§ 1% other

Fuel composition: 28% waste, 72% saline solution (Phosphate Buffer Solution, KOH)

SMFC

Graphite plates

pH probe openingIncubation at 25±2°C for 4 weekspH=7,0±0.2

§ Open Circuit Voltage (mV)§ Power Density (mW/Kg)§ Current Density (mA/Kg)§ Coumbic Efficiency (CE)

SMFC: acquisition data system

Sketch of the equivalent circuit of the MFCs measurement chain.

METHODS: MFC CHEMISTRY AND MICROBIOLOGY

Ionic Cromatography

Standard Methods(2012)

Metabolites

Organic load removal(COD, TOC), N, P

Electroactivebiofilms

Specific PD:1.75 mWm-2Kg-1

Maximum CD: 16 mAm-2Kg-1

Columbic efficiency: 5%*

RESULTS: POWER OUPUTS

-0,05

0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0 5 10 15 20

V

mA/m-2Kg

1st week

2nd week

3rd week

4th week

0

0,5

1

1,5

2

2,5

0 5 10 15 20

V

mA/m-2Kg

1st week

2nd week

3rd week

4th week

AD energy conversion efficiency accounts for about 15%. (Bogner et al., 2007)

OFMSW SMFC: CHEMISTRY Parameters Units Waste (W) Bioslurry(B) MFC3 Δ MFC3/B

pH 4.9 4.6 7.1 154%

CODsol g L-1 76.1 80.1 30.1 37%

BOD5 g L-1 7.3 8.3 4.4 53%

TOC g L-1 49.6 44.5 17.7 40%

NH4+ mg L-1 95 22 2.1 2%

NO2- mg L-1 5 6 4.3 72%

NO3- mg L-1 194 197 5< 0

Ptot mg L-1 111 76 45.2 41%

Acetate, lactate, formiate, ossalate, succinate present!!

pH= 7.0±0.4

CATHODE: Propionibacterium fraunreichii, Bavariicoccus sp.,Lactobacillus casei, Lactobacillus paraplantarum, Bacillus spp.

ANODE: Clostridium tyrobutiricum, Lactobacillusparacasei, Propionibacterium fraunreichii,Pseudomonas aeruginosa.

OFMSW SMFC: BIOFILMS

BIOGAS AND BIOHYDROGEN PRODUCTION

MFCSpent

substrate

ShreddingPresser

Inoculum

Water

ANAEROBIC DIGESTER (37 °C)Stirring: 150 rpm

Gas phaseanalysis

Liquid phaseanalysis

OFMSW

BIOGAS AND BIOHYDROGEN PRODUCTION

Ø Microbial biomass (OD600)Ø pHØChemical Oxygen Demand (COD)ØBiogas composition (GC-TCD detector)

Fig.2: Cumulative BioH2 production over time. OFMSW: solid residues from the OFMSW. MFC SS: MFCs Solid Substrate

MFC-SS: 14.13 ml/gOFMSW: 3.76 ml/g

BIOGAS AND BIOHYDROGEN PRODUCTION

BIOGAS AND BIOHYDROGEN PRODUCTION

Fig.3: Cumulative methane production over time. OFMSW: solid residues from the OFMSW. MFC SS: MFC-Solid Substrate.

OFMSW: 13.31 ml/g MFC-SS: 4.56 ml/g

BIOGAS AND BIOHYDROGEN PRODUCTION

Fig.5: Biomass concentration trend over time along with the AD experiment with MFC-SS and OFMSW solid residues.

Biomass yield was higher with OFMSW

pH MFC-SS= 7.15±0.22 pH OFMSW = 4.85±0.9

OFMSW MFCs: CONCLUSIONS

MFCs spent substrate revealed to be a better substrate for BioH2 production than the OFMSW, with a higher yield and an increasing production over time.

With further improvements, MFCs can open new possibilities in the energy recovery from organic waste

Our calculations report for the SOLE MFC, an energyproduction of 20% in comparison to the production and combustion of methane in engines. The calculations of MFC+DF and MFC+AD energy production are in progress.

This research has been funded by the ItalianGovernment, with the PON project “Fuel Cell Lab“Innovative systems and high efficient technologies forpolygeneration” PON03PE_00109_1/F12.”

Acknowledgments

PON PROJECT 2007-2013 TITLE III Industrial developement and experimental research project “SMART GENERATION –Systems and sustainable technologies for energy productionPON03PE_00157_1/F19 -CUP I62E14000010007”

Acknowledgments

Ciro Florio, Domenico Pirozzi,Angelo Ausiello, Giuseppe Toscano

Elio Jannelli, Stefano Dumontet, Vincenzo Pasquale, Mariagiovanna Minutillo, Fabio Flagiello,

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Bio-Electrochemical Systems (BESs): a versatile technology

Fig.1: A high-level overview of the concepts associated with bioelectrochemicalsystems. (Rabaey K & Rozendal R.A., 2010)

Membrane

Catalysts

Materials

Configuration

Source of reducing power

Microbial Electrolysis CellsMicrobial Fuel Cells

AN INTRODUCTION TO BIOELECTROCHEMICAL SYSTEMS

...AND BACTERIA

Endogenous microflora Mesophilic psicotrophics acid forming bacteria

Acetoclastic methanogenesis

Electrogenesis?

Solubility of complex organics: fats, proteins and carbohydrates by hydrolysis

Acid forming bacteria in waste

Acid formation (oxidation) reaction

4C3H7O2NS + 8 H2O 4 CH3COOH + 4CO2 + 4NH3 + 4H2S + 8H+ + 8 e-