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ANAEROBIC DIGESTION IN THE BIOREFINERY MARKET ECONOMY
N. BOON, M. CARBALLA, L. DE SCHAMPHELAIRE and W. VERSTRAETE
Lab. Microbial Ecology and Technology (LabMET) Faculty of Bioscience Engineering, Ghent University
Coupure L 653, B-9000 Gent, Belgium http://LabMET.UGent.be
Development of “high-rate” anaerobic treatment systems Completely mixed
(Bio)gas
influent effluent
Relative capacity: 1
Partial retention
Relative capacity: 3
Dense biomass
Relative capacity: 10
Enhanced contact & degassing
Relative capacity: 15
Source : After anaerobic high-rate treatment : State-of-the-art of new incentives (presentation of Prof. J. van Lier at the Anaerobic Experts Colloquium, Singapore, June 25, 2009)
UASB EGSB
Increasing digestibility & biomass conc.
IC
Number of non-lagoon industrial installations worldwide
(After Denis E.T., Applied Technologies, Wise)
Number of non-lagoon industrial installations worldwide (continuation)
Take home: • About 3500 anaerobic reactors worldwide • Top players : Paques bv 648 Biothane-Veolia 478 Global Water Engineering 195 Waterleau – Biotim 140 • Geographic distribution Europe 1174 Southeast Asia 894 North America 874 South America 303 Middle East/Africa 63
Technological : UASB 1000 EGSB 600 Anaerobic contact 370 Anaerobic upflow filter 90 Downflow filter 70
High-rate Anaerobic Wastewater Treatment 2009 • Decrease of excess sludge production by 90% ! • Up to 90% saving in space requirements ! • High loading rates (up to 35 kg COD.m-3.day-1), smaller reactors • No use of fossil fuels for treatment (saving ≈ 0.5-1 kWh / kg COD) • Production of energy as CH4 (3.8* kWh / kg COD converted) • Rapid start up with granular sludge (1 week) • No or very little use of chemicals (e.g. nutrients) • Anaerobic sludge can be stored unfed → campaign industries • Recovery of sulphur as H2S via produced biogas (closed water loops) • Perspectives for nutrients recovery (agricultural reuse, struvite)
Source : Anaerobic high-rate treatment : State-of-the-art of new incentives (presentation of Prof. J. van Lier at the Anaerobic Experts Colloquium, Singapore, June 25, 2009
Brewery effluent: decrease in CO2 emission!
Energy recovered: 17 ton COD x 0.85 (eff) x 3820 kWh** x 40% CHP eff. = 22 MWh-e/day ≈ 19 ton CO2/day (coal)
No energy consumption: 17 ton COD x 0.85 (eff.) = 15 MWh-e/day ≈ 12 ton CO2 avoided/day (coal)
Total CO2 emission avoided: 19 + 12 = 31 ton CO2 /day
≅ 380 €/d (at 20 €/ton CO2) ≅ 140.000 €/year
Coal powered electricity plant: 0.86 ton CO2/MWh-e
Source : Anaerobic high-rate treatment : State-of-the-art of new incentives (presentation of Prof. J. van Lier at the Anaerobic Experts Colloquium, Singapore, June 25, 2009
Loading capacity (kg COD.m-3.d-1) 10 – 35
Energy output (MJ.m-3 reactor installed.d-1) 55 – 3901
Electric power output (kW-e.m-3 reactor installed)
0.25 – 1.71,2
CO2 emission avoided (tonCO2.m-3.y-1, compared to coal-driven power plant)
1.9 – 13
Assumptions: 1 80% CH4 recovery relative to influent COD load 2 40% electric conversion efficiency using a modern combined heat power (CHP) generator Intermediate values are obtained by linear interpolation.
Energy output and CO2 emission reduction using AD systems 2009 state-of-the-art
Source : Anaerobic high-rate treatment : State-of-the-art of new incentives (presentation of Prof. J. van Lier at the Anaerobic Experts Colloquium, Singapore, June 25, 2009
COMP. LIRA (CLNSA) - Nicaragua
UAC Reactors - 102,000 kg COD/d
Corn Products Amardass (Starch) - Thailand
ANUBIX™ - 150,000 kg COD/d
I. Control of biological CH4 production/removal is essential in the context of global warming.
III. The bio-economy has started AD fits in all scenario’s of renewable energy. Yet, it is not in the front line of attention.
Upsurge of CH4 related basic bioscience is needed
AD must be integrated in the biorefinery economy
A. NEW CH4 BIOSCIENCE
B. INTEGRATION OF AD IN THE BIOREFINERY MARKET ECONOMY
C. SERENDIPITIES
D. DREAMS
E. RECAP
P = Production R = Removal
1. PATHWAYS
• Flux-balance modeling calculate actual routes
(Stolyar et al., 2007; Molecular Systems Biol. 3:92 ) (Yu et al., 2006; Biot. Bioeng. 93: 424-433)
CH4 + CO2
(Karakashev et al., 2006; AEM 72: 5138-5141) (Ishi et al., 2006; AEM 72: 5093-5096)
• Acetate
Cleavage Methanosarcinales
Oxidation-Reduction Clostridium-Methanomicrobiales
A. NEW CH4 BIOSCIENCE
Question: Is it good that they take the scenic route?
P
From micro-electrodes
(de Beer et al. 1996, Appl. Microbiol. Biotechnol. 46: 197-201; LabMET)
A. NEW CH4 BIOSCIENCE 2. THE IN-DEPTH ANALYSIS OF THE GRANULE
From micro-electrodes To NMR/ NanoSIMS/ Synchotron
(Lens et al. 2009, unpublished results)
The granules are full of water
They have some 20% pores
Their metabolic routing can be made visible
Low-T1 regions (precipitates, dead biomass)
High-T1 regions (biomass)
cavities
SignalfromTSEmeasurement
A. NEW CH4 BIOSCIENCE 2. THE IN-DEPTH ANALYSIS OF THE GRANULE
3. CELL YIELDS
Determine the number of copies of 16 S rRNA genes x cell volume calculate cell yield
(Du Hamel & Edwards, 2007; EST 41: 2303-2310)
A. NEW CH4 BIOSCIENCE
EMERGING CONCEPTS
P
• Methanogens are specialized in chronic energy shortage (as all Archaea) (Valentine et al., 2007; Nature. Rev. Microb. 5: 316-321)
• Methanogens are “weak”
• AD consortia are “conservative”
• Dechlorinators are still weaker
Only Methanobrevibacterium smithii survives the gastro-intestinal system with its enzymes, bile salts, etc… (Buck et al., 2007; PNAS 104: 10643-10648)
Any change of temp, pH, conc “hypobiosis”
The anaerobic dechlorinators have a factor 5 -10 less efficient coupling in e-transfer (Duhamel & Edwards, 2007; EST 41: 2303-2310)
EMERGING CONCEPTS
• Methanogens in competition/associaton with dechlorinators
(Duhamel & Edwards, 2007; EST 41: 2303-2310)
CH3OH
Methanomicrobiales CH4
Sporomusa Ac + H2
Geobacter sp.
Dehalococcoides sp. TCA CDCE VC C2H2
TCE
CDCE
A. NEW CH4 BIOSCIENCE P
3. COFACTORS/SHUTTLES/NANOWIRES • Metabolites of Gneg can transfer electrons
for Gpos bacteria (Hai et al. , 2008; Appl. Microbiol. Biotechnol. 77: 1119–1129; LabMET)
• Humic acids can be important e-shuttles (Peretyazhko & Sposito, 2006; Geoderma 137: 140-146)
• Nanowires Propionate CH4 + CO2 Pelotomaculum Methanothermobacterium (Gralnick & Newman, 2007; Molecular Microbiol. 65: 1-11)
A. NEW CH4 BIOSCIENCE
Take home: Plenty of molecular mechanism waiting to be engineered
P
4. NEW SPECIES
Bulking granules - Anaerolinea themophila - KSB3 (Yamada et al., 2007; ISME J. 1: 424-433)
LCFA degraders - Syntrophomonadaceae (by RNA based SIP) (Hatamoto et al., 2007; AEM 73: 1332-1340)
- Syntrophomonas zehnderi (Sousa et al., 2007; Int. J. Syst. Evol. Micr. 57: 609-615)
Acid tolerant MPB
A. NEW CH4 BIOSCIENCE
H2 + CO2 CH4 Methanobacterium spp.
(Kotsyrbenbo et al., 2007; AEM 73: 2344-2348)
pH 4.5
15°C
P
1. Anoxic methane removal (Hinrichs et al. 1999; Nature 398: 802-805; Boetius et al. 2000; Nature 407: 623-626)
Carbonate chimney formed by anoxic methane microbial mats in the Black sea.
Archaea-Bacteria consortia that oxidize methane anaerobically. ANME (Metanotrophs Archaea)
SRB (Sulfate Reducing Bacteria)
Take home: Still lots of unexpected microbiological discoveries ahead
A. NEW CH4 BIOSCIENCE R
(Van De Woestyne et al. 1994; FAO FEUR Technical Series; LabMET)
DRANCO Installation
Brecht, Belgium
3 MegaWatt
2. Oxic methane removal ENFORCED PREVENTION OF CH4 EMISSIONS
Landfills: 15% anthropogenic methane emissions
Take home: Reactor based AD of MSW (DRANCO, DICOM,…) decreases anthr. methane emissions with 90%
A. NEW CH4 BIOSCIENCE R
2. Oxic methane removal
* Bioaugmentation of soil
to produce inocula for soil bio- augmentation
Average removal of 800-1000 kg CH4/ha.yr (Boeckx et al., 1997; Nutrient Cycling in Agro-
ecosystems 49: 91-95)
* Coupling of AD to biogas conversion by methanotrophs
to produce chemicals from CH4: SCP, PHB,…
(Helm et al., 2006; JAM 101: 387-395)
A.NEW CH4 BIOSCIENCE R
WATER
Source separated wastes
FARM
CROPS
BIOREFINERY CONSUMERS
CONVERSION PRODUCTS
Residues Secondary products
MINERAL FERTILIZER
ENERGY
Clean & green
BIOTECH UPGRADING
Take home: 10-20% of the biomass flow will need upgrading
Top opportunity for AD
THE BIOECONOMY
I. BETTER BIOCATALYST
II. ADVANCED RECOVERY
I. Better means to deal with the biocatalyst are needed Default values about the microbiology Use molecular methods
- DGGE lanes - Phylogeny trees
We need to get from these:
• Concepts
• Indexes
• Benchmark values
We need to manage these communities
MRM
1. Who is there: 16 S DNA genes
2. Who is doing it with whom DGGE patterns + interpretations
Three new tools to measure maturity
• Range-weighted richness
• Dynamics of change of the gel
• Pareto-Lorenz plot of the gel
: carrying capacity of the system
: level of communication
: level of functional organization
THE “MICROBIAL RESOURCE MANAGEMENT” MRM APPROACH
DGGE-patterns
(Marzorati et al., 2007; Appl. Environ. Microbiol. 73: 2990-2999; LabMET)
THE MICROBIAL RESOURCE MANAGEMENT
Propionate oxidizing bacteria (POB) • At least four phylogenetic groups
• Clear functional redundancy (MAR-FISH)
We must be able to transfer this science into management terms
(Ariesyady et al., 2007; AMB 75: 673-683)
%
Smithella short rod-uncultured 52-62
Syntrophobactet 16-31
Syntrophobacter 6
Smithella long rod-uncultured minor
THE MICROBIAL RESOURCE MANAGEMENT
(Smits et al. 2009; unpublished results; LabMET)
Ripley index: IA/TA ratio Intermediate Alkalinity (IA) Total Alkalinity (TA) Succesfull digestion occures with a Ripley index below 0.3
(Ripley et al. 1986; Journal WPCF 58: 406-411)
Take-home: The index of Rr for Bacteria is correlated with the Ripley index.
Question: What additional info can it hold?
Rr
THE MICROBIAL RESOURCE MANAGEMENT
Stable community Low dynamics
(%Λchange/week=24%) F20 value of 50-60%
Well-functioning reactor
Process engineers need simple “GPS” guidelines The influx of genes is broad spread of the gel
The AD community is evolving in a healthy way moving window of the gel
the AD community is at strength Pareto- Lorenz structure of the gel
We need more of these simplified approaches
PRAGMATIC MRM - APPROACH
MRM - APPROACH TEN NEW LEVERS
1. APPLY QUALITY SEED OF MPB E.G. TO LANDFILL
Worldwide shipment of granular sludge
2. BIOAUGMENTATION OF FERMENTATIVES
• E-lysis (Suez) … % more biogas from biosolids • Hydrogen producing bacteria (HPB)
E. coli, Enterobacter cloacae at 35°C Coldicellulosyruptor at 35°C (Bagi et al., 2007; AMB 73: 473-482)
• Bacillus/Pseud/Actino mix – 29 % more biogas – 54 % less propionic – 37% less DMS (Duran et al., 2006; AMB 73: 960-966)
• Clostridium ludense better lipid conversion (Cirne et al., 2006; J. Chem Tech. & Biol. 81: 1745-1752)
MRM - APPROACH TEN NEW LEVERS
3. BIOSUPPLEMENTATION New substrates e.g. glycerol; anaerobic cometabolism? (Ma et al., 2008; Biotechnol. Lett. 30: 861-867; LabMET)
Rare earth elements (Noyola et al., 2005; Wat. Sci. Technol. 52: 275-281) (Espinoza et al., 1995; Wat. Sci. Technol. 32: 121-124)
4. REDOX BUFFERS/SHUTTLES Humic acids promote propionic acid removal (Stragier et al., 2007; unpublished)
5. PHAGES Selective control of SRB by viral adaptation to these hosts (Crill et al., 2006; Genetics 154: 27-37)
MRM - APPROACH TEN NEW LEVERS
6. A HYDROGEN BASED VARIABLE GAS CONTROLLER
(Rodriguez et al., 2006; Wat. Sci. Techn. 54: 57-62)
7. DECREASE OF NH3 BY SORPTION ON H2SO4/C
(Chou et al., 2006; J. Env. Sci. China. 18: 1176-1181)
MRM - APPROACH TEN NEW LEVERS
8. PRESSURE SWING AD( + 1.5 ATM; - 0.5 ATM) Gas plasticization of polymers WAS: - factor 1.5 more COD converted to biogas - 8 -10 higher rate (Schimel, 2007; Biot. Bioeng 97: 297-307)
9. DRY WATER (J. Am. Chem. Soc. 2008, 130, 11608)
MRM - APPROACH TEN NEW LEVERS
H20
Silico 1 kg powder stores 150 L CH4
Coating
(≈ natural clathrate)
10. ENHANCED PROPIONIC ACID DEGRADATION (EPAD) system Can we combine a CSTR and a propionate-specific UASB? (Ma et al. 2009; Water Research, in press; LabMET)
MRM - APPROACH TEN NEW LEVERS
CSTR EPADSeparator
Membrane
EPADUASB
Recy
cle
Biogas
Biogas
Biogas
Biofuel Production Processes Fuel Unit processes Wastestream Reliability
Pure Plant Oil Pressing, chemical extraction, extra refinery
Pressed cake High
Biodiesel Esterification Glycerol residue High
Bio-ethanol Fermentation, distillation,…
Distillery slops direct
Evaporation condensates
High
Fisher-Tropsch Diesel
Gasification, FT synthesis
Light oils High
Biogas kWh-electric + kWh-thermal
Anaerobic digestion + MFC after treatment
None!!! Thus far: poor Now: OK
BIOREFINERY Example 1
• The maxifuels concept (Ahring et al., 2007; unpublished) (http://www.biocentrum.dtu.dk)
Lignocellulose 1 Steam explosion 2 Enzymes 3 C6 fermentations 4 C5 fermentation 5 Lignin separation 6 Distillation
7 Biogasfermentation (used on site) Endpoints: - Ethanol - Lignin Throughput: - Pilot: 100 ton DM/year - Demo: 40,000 ton DM/year planned
Buffertank/ transport tank
Enzymes and Yeast
Centrifuge
Bio-ethanol
Lignin (clean solid fuel)
Lignocellulosic biomass
Pre treatment Process
(Ethanol-free effluent)
Recycling of process water
C6 ferm. 37 °C
Distillation
Pre treated biomass
Liquid Fertilizer
Maxifuel Pilot Plant The Technical University of Denmark
Biogas
C5 ferm. 70 °C
Hydrogen
Funded partly by the Danish Ministry of Energy and Transport Commercialized by BioGasol (www.biogasol.com)
UASB (AD) 55 °C
Total: 16 Tanks and reactors up to 3 m3
Pilot plant
Maxifuel Pilot Plant The Technical University of Denmark
Optimized use of the biomass Oxidized in the pre-treatment
Ethanol from glucose
Ethanol from xylose
Lignin for combustion
Biogas
Organic material in the process water
Mass balance based on COD
3% 5% 19%
20% 19%
35%
Maxifuel Pilot Plant The Technical University of Denmark
Bornholm
Salt removal
Biomass
Separation
Distillation
Bio-pellets
Hydrogen
Ethanol
Power
C6 Fermentation
Wet oxidation
C5 Fermentation
Anaerobic Digestion Heat
Ethanol
+ Other high value products
40,000 ton biomasse
10,000 ton
500 m3
10 mn litres
BIOREFINERY Example 2 • Dry continuous AD of energy crops
(De Baere et al., 2007; unpublished)
Energy crop Lignocellulose 1 Chopper to < 1 cm 2 DRANCO
3 Residue to land
Endpoints: ▪ kWhel 40 % netto output ▪ Clean nutrients + Humus
Throughput: - Demo existing Nüdstedt 4000 t DM/yr
A. NEW CH4 BIOSCIENCE
C. INTEGRATION OF AD IN THE BIOREFINERY MARKET ECONOMY
I. BETTER BIOCATALYST II. ADVANCED RECOVERY
1. MORE REDUCING EQUIVALENTS
(Ueno et al., 2007; EST 41: 1417-1419)
1.1. Combining H2 & CH4
Garbage Packed bed 80% COD recovery of which
1/3 as H2
2/3 as CH4
Packed bed
60°C
4.2 d 55°C
6.8 d Residence time =
H2 CH4
II ADVANCED RECOVERY Five extra examples
1. MORE REDUCING EQUIVALENTS
1.2. Combining CH4 and Bio-Electric Systems (BES)
Two examples
- High strength waters
- Low strength waters
Five extra examples
II ADVANCED RECOVERY
- High strength wastewater:
– First: anaerobic digestion – Second: MFC or bio electrochemical
hydrogen production
BES/ Direct
- Low strength wastewater: – First: conventional aerobic waste water
treatment – Second: anaerobic digestion of excess
sludge – Third: treatment of digestate in MFC
BES/ BEAMR
2. CALCIUM REMOVAL
Cardboard paper factory
Wastewater UASB
80% closed waterloop
CaCO3 re-used in paper production
Posttreatment and discharge
II ADVANCED RECOVERY
BIODEC (Austep, pilot scale)
- Removal of excess ca. (60%)
- VFA (80%)
Five extra examples
3. PHOSPHATE 3. A. Chemical
• Potato factory
(Moerman et al., 2009; Wat. Res. 43: 1887-1892; LabMET)
• Sewage treatment plant
(Shu et al., 2006; Biores. Tech. 97: 2211-2216)
Colson process Moerman process
High quality plant-derived struvite
About 0.5 kg crude struvite
per IE per year
II ADVANCED RECOVERY Five extra examples
3. PHOSPHATE 3. B. Biological: The ureolytic bio-catalytic process
+ The process removes down to 2 mg PO43-- P/L
(Desmidt et al., 2009; Wat. Sci. Technol., in press; LabMET)
+ The cost is competitive with Fe3+
(Carballa et al., 2009; J. Chem. Technol. Biotechnol. 84: 63-68; LabMET)
AD Effluent Urea
MgO
Mg NH4 PO4 ↓
Struvite
Take home: Novel uses of struvite are needed
II ADVANCED RECOVERY Five extra examples
4. SULFUR • Recovery of So via O2 limitted Thiobacillus (Thiopaques)
• Recovery of H2S deposited energy by
a Bio-Electric System (BES)
H2S colloidal S + KWh (Rabaey et al., 2006; EST 40: 3218-5224; LabMET)
II ADVANCED RECOVERY Five extra examples
5. RECLAIMED WATER 5.1 UF-membrane The An-MBR (e.g. Thermophilic membrane fluxes at 20L/m2.h) (Jaison & Van lier, 2006; J. Mebr. Sci. 284: 227-236)
5.2 IO-membrane Manure/other suspensions
CSTR
Dry organic solids
Coagulants Removal of particles larger than 250 µm
Water
Biogas
II ADVANCED RECOVERY Five extra examples
Take home: In a few steps to discharge!
MBR
IO National Stand. Fertilizer
1. Controlling the unwanted “parasitic” MPB & SRB in sewerage systems by
• Formaldehyde • Fe-rich WAS • MFC • … (Lehua et al., 2007; Wat. Res. 42: 211-217; LabMET)
C. SERENDIPITIES
2. Bacteria which rapidly remove obnoxious compounds e.g. methanethiol, DMS, … (de Bok et al., 2006; AEM: 7540-7547)
(Note: In the Cambi process, sludge cooking gasses are de-odorized in digester)
C. SERENDIPITIES
3. Dried anaerobically digested municipal wastewater sludge as source of powerful bacilli spores To hydrolyse organic matter To produce H2
(Kalogo & Bagley, 2007; Biores. Techn. 99: 540-546)
4. ENOS: engineered natural sorbants (Tang et al., 2007; EST41: 2901-2907) Pea, cornstalk, AD residues modest hydrothermal treatment (e.g. 200°C water 5h.) More aromatic and sorbtive to modulate bioavailability
C. SERENDIPITIES (continued)
58
Note: Solar algal panel of 10 000 m² => 23 kW/ha power unit
Anode Cathode
ELECTRICITY
MFC
BIOGAS
Algal growth
AD
2750 Wh m-2 d-1
Per m2 footprint
60 ton DM ha-1 yr-1
=
16 g DM m-2 d-1
(De Schamphelaire & Verstraete 2009; Biotechn. Bioeng. 103:296-304; LabMET)
5. Solar algal panel – AD – MFC concept C. SERENDIPITIES (continued)
Efficiency of renewable energy captation
Wind energy – Wind turbines 50 %
Solar energy – Photovoltaic cells 12 – 18 %
Solar energy – AD & MFC 0.4 %
C. SERENDIPITIES (continued) 5.Solar algal panel – AD – MFC concept
D. THE DREAMS 1. Biogas for mobility Ugly duck Beautiful swan
Biodiesel
Bio-ethanol
BTL (biomass to liquid) by ° FT-conversion
° AD conversion
Can cover 50% of the “EU 2020 Biofuel for mobility” without change in landuse (AD 2007)
(Weiland, 2006; Eng. Life Sci.6, 302-309)
20.000 km/ha
33.000 km/ha
63.000 km/ha
66.000 km/ha
2. AD Biogas based sustainable organic chemistry
Commodity chemicals with AD as a first line “all mash” biomass convertor
Biocatalytic conversions Conventional
petro-chemistry
Upgrading to syngas by Fisher Trops
“All mash” biogas convertor
All kinds of biomass
Humus + Clean nutrient
Flexible crop production
(Datar et al., 2004; Biot. Bioeng. J. 86: 587-594) (Yeuneshi et al., 2005; Biochem. Eng. J. 27: 110-119)
D. THE DREAMS
3. The sustainable sugarcane system
D. THE DREAMS
Sugarcane whole crop
Bagasse Leaves
Residues of vinasses bagasses leaves
Ethanol
N, P, … nutrients as NSF
Biogas
Sugar juice Ethanol fermentation
Hydrolysis
AD
60
25
Carbonisation Biochar
15
100
D. THE DREAMS
Take home: * Four types of “energy” recovery
+ * Carbon credits
+ * Green energy certificates
(Weiland et al. 2009. In: Biofuels. (W. Soetaert and E.J. Vandamme, Editors). pp 172-195. John Wiley & Sons Ltd. ISBN: 978-0-470-02674-8; LabMET)
3. The sustainable sugarcane system
4. Decentralized sewage treatment (Family level)
D. THE DREAMS
25% energetic efficiency
UASB-ST 20°C
700 L biogas/d
MFC Black water 5 L/I.E. d 17 g COD/L = 4.25 kg COD/d
Small village not connected to grid (50 I.E.)
Effluent 1.3 - 1.7 g COD/L ≈ 0.40 kg COD/d
0.4 kWh/d = 17 W
Solids to be removed ounce a year
1.4 kWh/d = 58 W
D. THE DREAMS 4. Decentralized sewage treatment (Suburb level)
The UASB/TF system
Consistently sufficient to have 60 mg BOD/t; 180 mg COD/L and 60 mg TSS/L (De Almeida et al. 2009, Wat. Sci. Tech. 59: 1431-1439)
5. AD for poorly accessible oil
• In heavy oil deposits, less than 20% of the energy can at present be recovered
• Syntrophus aciditrophicus generates methane from crude oil
• By providing [nutrients + microbiota], one can possibly harvest 20% extra
(Larter, 2008; Nature 451)
D. THE DREAMS
E. RECAP
1. AD fits perfectly in the hypes about - Abatement of global warming - Renewable energy
2. The Microbial Resource Management of AD consortia is key to further success
3. Various AD – add on Technologies are evolving recovery of
• CaCO3 • Struvite • Sulfur • Left-over VFA to MFC • Reclaimed water
4. The serendipities and dreams are numerous
• AD sciences & businesses are booming • AD deserves to be promoted both as a first
line biomass convertor as well as a waste treatment technology
BOTTOM LINES
The best is yet to come
N. Boon LabMET
M. Carballa LabMET
Best greetings from Ghent University
L. De Schamphelaire LabMET
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