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ANAEROBID DIGESTION IN FULL EVOLUTION
W. VERSTRAETE
Lab. Microbial Ecology and Technology (LabMET)Faculty of Bioscience Engineering, Ghent University
Coupure L 653, B-9000 Gent, Belgiumwww.LabMET.UGent.be
From Less waste
Less sludge production Lower carbon footprint
To
More energy recuperation Digestion is now all about kWh
1. THE DRIVERS
1. THE DRIVERSTable 1: Examples of subsidies in different European countries for green electricity production by anaerobic digestion of agricultural waste. These values differ based on the size of the plant, and additional bonuses (Bundesministeriums für Umwelt, Naturschutz und Reaktorsicherheit - BMU, 2011).
Country Type €/MWhel Guaranteed years
Belgium Quota (Green certificates) 120 10
Netherlands Price regulation (bonus) 79 12
Spain Price regulation 108 – 159 15
France Price regulation 75 – 90* 15
Germany Fixed compensation 85 - 307 20
Austria Price regulation 124 – 169 12
Italy Quota (Certificati verdi) 220 – 280 15* + additional bonuses (20 – 50 €/MWh)
:Take home:100-300€/tonCOD;150 Euro /ton DS
2. THE EVOLVING BIOCATALYTIC PROCESS
Carbohydrates
Fats
Proteïns
Sugars
Fatty Acids
Amino Acids
Hydrolysis
Carbonic Acidsand
Alcohols
HydrogenCarbonDioxide
Ammonia
Hydrogen
Acetate
MethaneCarbon dioxide
30%
70%
Acidogenesis Acetogenesis Methanogenesis
HM = Hydrogenotrophic Methanogenesis
AM = Acetoclastic Methanogenesis
Bacteria Archaea
Normal waste treatment reactor systems / The old route
2. THE EVOLVING BIOCATALYTIC PROCESS
70%
2. THE EVOLVING BIOCATALYTIC PROCESS
Proposed robust methanogenesis system, based on syntrophic acetate oxidizing (SAO) bacteria and robust HM for intensive energy production reactor systems. The new route !!!
2. THE EVOLVING BIOCATALYTIC PROCESS:RATE LIMITING STEPS
1. Higher VFA Acetate + H₂
• Syntrophic acetogenic bacteria (SAB)
Exp: SyntrophobacterSyntrophomonas…
Weak bacteria td = weeks
Molecular monitoring:
- Generic: not available-Specific: 16SrRNA probes
This ‘go between ‘ group is very weak
pH ₂ < 10-4 atm
2. THE EVOLVING BIOCATALYTIC PROCESS:RATE LIMITING STEPS
2. Acetate CO₂ + CH₄• Acetoclastic methanogens (AM)
Exp: Methanosaeta
Methanosarcina
Weak archaea td = weeks
Robust archaea td = days
Molecular monitoring:
- Generic: All methanogenic archaea have methyl coenzym-M reductans
-Specific: 16SrRNA probes There are now molecular methods to monitor these bugs !
‘mcr / mrt’ gene
2. THE EVOLVING BIOCATALYTIC PROCESS:RATE LIMITING STEPS
3. H2 + CO2 CH4
Exp: - MethanomicrobialesMethanomicrobiumMethanoculleus
- MethanobacterialesMethanobacteriumMethanobrevibacter
Moderate archaea td = weeks
Robust archaea td = days
Molecular monitoring:- Generic: All methanogenic Archeae have ‘mcr’ gene- Specific: 16SrRNA probes We must try to work with these robust guys
2. THE EVOLVING BIOCATALYTIC PROCESS:RATE LIMITING STEPS
4. Acetate CO₂ + H₂
Weak bacteria td = weeks
Robust bacteria td = days
MesoSynergistic group 4Clostridium ultenenseSyntrophaceticus schinkiiTepidanaerobacter acetatoxydensThermoacetogenium phaeumThermotoga lettingae
ThermoMolecular monitoring: All [homoacetogens] have the Formyl Terta Hydro Folate Synthetase (FTHFS) gene For these group op SAO : one works best Thermo
[Reversibacter of SAO]
pH ₂ ≤ 10-5 atm
Characteristics of Methanosaeta and Methanosarcina
Parameter Methanosaeta Methanosarcina
μmax (d-1) 0.20 0.60 Ks (mg acetate/L) 10 - 50 200 - 280NH4+ (mg/L) < 3 000 < 7 000Na+ (mg/L) < 10 000 < 18 000pH-range 6.5 - 8.5 5 - 8pH-shock < 0.5 0.8 - 1 Temperature range (°C) 7 - 65 1 - 70 Acetate concentration (mg/L) < 3 000 < 15 000 (De Vrieze et al.2012 ; Biores Technol 112:1-9 ,LabMET )
The Methanosarcina can stand high conc of ammonia and salt
2. THE EVOLVING BIOCATALYTIC PROCESS
• Food wastes Lactic acid - At low Bv and high HRT (=20d) mainly Methanoculleus as
Hydrogenotrophic Methanogens (HM)
YET: - At high Bv ≈ 36 g COD/L.d HRT = 4 d No conventional HM, archaea are
mainly Methanosarcina
(Shin et al., 2010; Wat. Res. 44: 4838-4849)
At high Bv : one needs to have the Sarcina -‘elephant’
2. THE EVOLVING BIOCATALYTIC PROCESS
CSTR35°C
2.THE EVOLVING BIOCATALYTIC PROCESS
Tentative overview of integrative tools for monitoring of methanogenic bioreactors
Conventional Unit Benchmark
Gas per unit load
Fatty acids over bicarbonate
__________________ Conductivity
(L biogas .L-¹ d-¹)/ gCOD.L-¹ d-¹
Equiv. acetate/Equiv.HCO �₃
mS/cm
≥ 0.5
≤ 0.5
≤ 30
(De Vrieze et al.2012; Biores.Tech. 112:1-9 ,LabMET )
The conventional monitoring parameters are ‘weak’
Advanced Unit BenchmarkTotal SAO FTHFS genesTotal bacteria 16SrRNA genes
Total Methanogens mcrA genesTotal Bacteria 16SrRNA genes
Methanosaeta 16SrRNA genesMethanosarcina 16SrRNA genes
%
%
%
≥ 10
≥ 10
Normal ≥ 10*Heavy duty ≥ 1*
*Need to be further developed
FTHFS = Formyl Tetra Hydro Folate SyntheseMCR = Methyl Coenzyme Reductose
2.THE EVOLVING BIOCATALYTIC PROCESSTentative overview of integrative tools for monitoring of methanogenic bioreactors (cont.) (De Vrieze et al. 2O12; Biores .Tech. 112: 1-9; LabMET )
We can monitor the ‘ microbial machinery‘ we deal with!
2.THE EVOLVING BIOCATALYTIC PROCESS
The moral:-AD depends on a ‘microbiome’ = a team of microbes which evolved together to cooperate ; theAD microbiome operates in ‘small steps ’
•Always very critical: SAB! Impose a long SRT • Critical in high rate reactors: SAO bacteria Thermo is best
- How to stimulate / retain these SAB & SAO?e.g. Support matrices which enrich [SAB/SAO - HM](Chauhan & Ogram 2005; BBRC 327: 884 – 893) Carrier materials can be of help-We need an Early Warning Indicator (EWI) for these groups! Recently a new find : Ratio VVZ /Ca is very helpful in case of oily feed (Wurdemann et al. 2012 ; in press )
3. THE EXPANDED POTENTIAL
• Methanogenic degradation of PAH is possible
Naphtalene Phananthrene 25 °C CH4
Anthracene + 27 – 35 kJ/mol Pyrene for the MPB Chrysene
(Dolfing et al., 2010; Microb. Biot. 2: 566-574)
Take home: AD is a “omnivalent” gasification process
• Geobacter in syntrophy with - Methanosaeta - Methanosarcina
Fatty acids & Aromatics present in non-productive coal
(Jones et al., 2010; AEM 76: 7013-1022)
Biogas
3. THE EXPANDED POTENTIAL• Terephthalate (TA) converstion to biogas
TA Acetate + H2 + CO2
Butyrate “Recycling”
Acetate + H2
CH4 + CO2
(Lykidis et al., 2011; The ISME Journal 5: 122 – 130)
Take home: Methanogenesis proceeds by meandering metabolism; small ‘spenders’ seize dominance in the AD energy flow
4. BIOAUGMENTATION• Cold methanogens : 0.2 m3 biogas m-3 reactor d-1 at 5 – 7 °C (McFadden 2010; New Sci. 2785: 14)
• Hydrogen producing bacteria (HPB) E. coli, Enterobacter cloacae at 35°C Caldicellulosyruptor at 55°C
(Bagi et al., 2007; AMB 73: 473-482)
• LCFA degraders - Clostridium ludense : better lipid conversion
(Cirne et al., 2006; J. Chem. Tech. & Biol. 81: 1745-1752)
- Syntrophomonas zehnderi on sepiolite for facter 2 faster conversion of oleate
(Cavaleiro et al., 2010; Wat. Res. 44: 4940 – 4947)
4. BIOAUGMENTATION
• Constructed ligno-cellulosic cultures:
Mesophilic:
Methanos®: a combination of 2 Clostridia sp.;
gas production from maize +20%; Bv x 2
Extra netto gain per m³ reactor per year: 50 – 100 € (personal info)
Thermophilic:
Pretreatment of 12h of cassava residues with inoculum :
from 130 to 260 mL biogas/g VSS treated.
(Zhang et al., 2011; Biores. Tech. 102: 8899-8906)
4. BIOAUGMENTATION
• “Super” Methanosarcina acetivorans
Plasmid with broad-specificityesterase of Pseudomonas
GMO which could growon acetate, formate, hydrogen, methanol
+methanol released from - methyl-propionate
- methyl-acetate
(Lessner et al., 2010; mBio 1: issue 5)
Gradually , effective inocula enter the market scene
5. MONITORING THE METHANOGENIC “COLLABOROME”
DGGE-patterns
1. Who is there: 16 S DNA genes
2. Who is doing it with whom
DGGE patterns + interpretations
Three new toolsTo measure
maturity
• Range-weighted richness: Rr
• Dynamics of change of the gel: Dy
• Pareto-Lorenz plot of the gel: Co
(Marzorati et al., 2007; Appl. Environ. Microbiol. 73: 2990-2999; LabMET)
5. MONITORING THE METHANOGENIC “COLLABOROME”
(Carballa et al., 2011; Appl. Microbiol. Biotechnol. 89: 303-314; LabMET)
Richness /diversity of species is necessary
Good Poor performance
TVATAC
Dy (Dynamics of change)
(*Pycke et al., 2011. Water Sci. Technol. 63: 769-775; LabMET; **Zamalloa et al., 2012; Appl Microbiol Biotechnol 93:859–869; LabMET; ***Read et al. 2011. Appl Microbiol Biotechnol 90: 861-871; LabMET)
***(Low (<7%), Moderate (7–24%), High (>24%)
The microbiome must be dynamic ; the ghetto does not work
Co (community organization)
Also here the 80/20 rule is valid !
Perfect
evenness
Ecological Pareto
(Zamalloa et al., 2012; Appl Microbiol Biotechnol 93:859–869; LabMET)
Lab scale6. PROCESS TECHNICAL AIDS
• Dosing electron sinks as H2-scavengers Examples - Essential oils
- Tannins - Saponins - Flavonoids
(Palra & Saxena, 2010; Phytochemistry 71: 1198-1222)
Such plant secondary metabolites inhibit HM in the rumen
Take home:
Some natural substances can be inhibitive
Lab scale6. PROCESS TECHNICAL AIDSAD & BES: Bio-electochemical Systems (BES)
(Logan et al., 2006; Env. Sci. & Tech. 40: 5181-5192; LabMET)
Take home:• Thus far - MFC: 1 kg COD m-3 d-1
- MEC: 5 kg COD m-3 d-1
• MEC-BEAMR: H2 is produced at 1/3 of the energy input of normal electrolysis
(Sleutels et al. 2009; Int. J. Hydrogen Energy 34: 9655–9661)
(Liu et al. 2005; Env. Sci. Technol. 39: 4317-4320)
Lab scale6. PROCESS TECHNICAL AIDS
Bio-electrochemical systems (BES)
Methanogenic aggregates are electrically conductive
µs/cm
o Water, alginate beads minimalo Geobacter species 1.4 ± 0.3o Aggregates 6-7 ± 3o Aluminium beads 11 ± 0.1(Malvankar et al., 2011 ; Nature Nanotechnology 6: 573-579)
Methane production depends on the transfer of electrical currents between various bacteria !!!
MEC in AD• Cathode and anode inside reactor
Electrolysis in the AD reactor 200-300 W installed/m³ reactor provided 25% higher biogas production
Electricity consumed only 25% of extra electrical energy gained
(Tartakovsky et al., 2011; Bioresource Technology 102: 5685-5691)
AD & BES
CSTR EPADSeparator
Membrane
EPADUASB
Recy
cle
Biogas
Biogas
Biogas
Enhanced Propionic Acid Degradation (EPAD) systemCan we combine a CSTR and a propionate-specific UASB?
(Ma et al. 2009; Water Research, 43: 3239-3248; LabMET)
Lab scale6. PROCESS TECHNICAL AIDS
• Increasing the surface of the solids
Sonication, heat, …
Grinding
Full scale6. PROCESS TECHNICAL AIDS
(Halalsheh et al., 2011; Biores. Technol., 02:748-752)
Physiso/chemical treatments are thus far not worth the trouble
cm²/ cm³ sludge % degradation
3000 25
6000 50
• Inverted Anaerobic Sludge Blanket (IASB)
Problem: LCFA cause sludge flotation washout + dirty effluent with normal UASB
Solution:Use of flotation instead of sedimentation as mainbiomass retention technique
(Alves et al., 2010; US 7.850.849 B2)
Full scale6. PROCESS TECHNICAL AIDS
Note: Also Paques and GWE have flotation based full scale reactors
• Temperature Phased Anaerobic Digestion (TPAD)
- Good pathogen removal due to short thermophilic stage- Better VS-removal with same reactor volume
(Adapted after Riau et al., 2010; Bioresource Techn. 101, 2706-2712)
Full scale6. PROCESS TECHNICAL AIDS
MesophilicHRT= 15d
TPAD-system HRTthermophilic = 3d HRTmesophilic = 12d
• Anaerobic Membrane BioReactor (AnMBR)
Low pressure * Fluxes 5 L/m².h * Biomass 3 – 5x more concentrated; digester volumes 3 – 5 x smaller * Capex -10%; Opex -40% * Water re-use facilitated
At present : 14 Kubota AnMBR in Japan(Kanai et al., 2010; Desalination 250 : 964 – 967; Christian 2009, www.adisystemic.com)
Full scale6. PROCESS TECHNICAL AIDS
High pressure
* Veolia and ADI on dairyAt present some 25 anMBRs; future of ‘pocket’digestors ?
6.1 Waters
Number of non-lagoon industrial installations worldwide
(After Totzke, Applied Technologies Inc.)
Full scale6. PROCESS TECHNICAL AIDS
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
Number of non-lagoon industrial installations worldwide
Full scale6. PROCESS TECHNICAL AIDS6.1. Waters
Take home:
Technological : UASB 1000 EGSB 600 Anaerobic contact 370 Anaerobic upflow filter 90 Downflow filter 70
Number of non-lagoon industrial installations worldwide
Full scale6. PROCESS TECHNICAL AIDS
6.1. Waters
Take home: - Mainly focussing on “cleaning-up”- In total some 3000 MWel worldwide
• The mastodons - COMP. LIRA (CLNSA) - Nicaragua
UAC Reactors102,000 kg COD/d
50 000 m³ biogas/d50 000 L fossilfuel/d
50m³
Full scale6. PROCESS TECHNICAL AIDS
Full scale6. PROCESS TECHNICAL AIDS
6.2. MSW (municipal solid wastes )
Anaerobic digestion of MSW in Europe:
About 200 plants in 17 EU countriesOWS,
Tenneville, Belgium About 6.0 million tons MSW (= 20 million IE ) treated per year; yields 3 000 MWel
Some 1.0 million tons MSW extra capacity per year
(De Baere & Mattheeuws 2010; Biocycle Febr. 24)
6.3 Manure & biomass
European Biogas Association:
7500 agricultural digesters across EU; Germany: 6000 !
Overall electrical capacity 2 280 MWel with a turnover of € 2300 billion per year
(Irish Farmers Journal, Refit moving forward, 05-03-2011)
6. PROCESS TECHNICAL AIDS
• The mastodons - Corn Products Amardass (Starch) - Thailand
ANUBIX™ - 150,000 kg COD/d 6 MW
Full scale6. PROCESS TECHNICAL AIDS
Biofuel Production ProcessesFuel 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-TropschDiesel
Gasification, FT synthesis
Light oils High
Biogas kWh-electric+ kWh-thermal
Anaerobic digestion + MFC after treatment
None!!! Thus far: poorNow: OK
7. FEEDSTOCKS
Biorefinery: The Ghent Project
7. FEEDSTOCKS
Crucial
Plant biotechnology
Industrial biotechnology
Environmental biotechnology
Thermochemical conversion
Sugarcanewhole crop
100% Bagasse+ leaves
Residues of• vinasses• bagasses • leaves
N, P, … nutrients as NSF
Sugar juice Ethanolfermentation
Hydrolysis
AD
Ethanol
60 %
Biogas 25 %
CarbonisationBiochar
15 %
(After Weiland, Verstraete & Van Haandel, 2009; Biofuels, 171-195; ISBN 9780470026748)
7. FEEDSTOCKS
Take home: Politics needed to make Biogas, Biochar and NSF more attractive
Normally only 40%recovery
Methanolic glycerol from biodiesel
Output nr 2
Acetoclasticmethanogenesis
7. FEEDSTOCKS
Methanol
Methyl-CoM
Methane
Output nr 1
Glycerol
Acetate
H2
1,3 Propane Diol(1,3 DPO)
(Bizukoje et al., 2010; Bioprocess Biosyst. Eng. 33: 507-523)
Take home: Metabolic cross-feeding in a binary culture of Methanosarcina mazei and Clostridium butyricum
Addition of co-substrates > 500gCOD/Le.g.
7. FEEDSTOCKS
Glycerol residues Grease and fat from slaughterhouse waste Whole crop maize Food wastes Household biosolids (Grass clippings from roadside
- Not well suited: high lignine content) (Pure blood or urine from slaughterhouse
- Not well suited: high N-content)
Take home: By adding concentrated co-substrates, the reactor productivity can be increased with a factor 5-10
!!
oAlgae: Lipid rich algae are best
Theorethical methane yield: 0.64-0.94 LCH4/gVS
Practical methane yield: 0.09-0.45 LCH4/gVS
(Sialve et al., 2009; Biotech. Adv. 27: 409-416)
(Chisti, 2007; Biotechnol. Adv. 25, 294-306)(Zamalloa et al., 2011, Appl. Energy, in press; LabMET)
If high productivities (>90 ton DM ha-1 year-1)+ high conversion efficiencies (>75%) + high loading rates (>10 kgCOD m-3 day-1)
Energy from microalgae can cost 0.09-0.17 € kWh-1
(Zamalloa et al., 2009; Bioresource Tech. 102: 1149-1158; LabMET)
7. FEEDSTOCKS
Micro-algae can be grown on non-agricultural soils ; yet the production is too costly and the digestion too difficult
UF/RO NEWaterUP-CONCENTRATION
SCREENING
A-line (Major flow)
SEWAGE
COARSE MINERALS
ANAEROBICDIGESTER
FILTER PRESS
P-RICH CAKE
BIOGAS
NITROGEN-RICH WATER
COMBINED HEAT AND
POWER UNIT. THE CO2 GOES TO THE ALGAL FARM
NATURAL STABLE
FERTILIZER (NSF)
PYROLYSIS BIOCHAR
BRINE
(Verstraete et al., 2009; Bioresource Techn. 100: 5537-5545; LabMET)
The “Zero-Waste” Water Technology
B-lineMinor flow (max 10 %)
7. FEEDSTOCKS
The “Zero-Waste” Water TechnologyUp-concentration of “raw” domestic organics
• Chemically assisted primary sedimentation (CEPT)
• Bio-floculation or A/B-Boehnke conceptLow HRT (0.4 – 1 h)High Bx (> 1.5 kg BOD kgVSS-1 d-1)
(Boehnke et al., 1998; Water-Engineering & Management 145: 31-34) AD
Coagulation + floculation
InfluentUF
Decantor AD
Clean permeate
7. FEEDSTOCKS
(Verstraete & Vlaeminck, 2010; 2de Xiamen Int. Forum on Urban Env.; LabMET)
In the near future , we have to retrofit all our STP ; we must put up-concentration and digestion upfront .
8. OUTLOOK AND CHALLENGES
CH4-saturated effluent of AD > 11 mg CH4/L
Up to 25% of produced methane in case of low strength waters
(Cakir & Stenstrom, 2005; Water research 39: 4197-4203) (Hartley and Lant, 2006; Biotech. and Bioeng. 95: 384-398)
1. Diffuse methane emissions from storage and effluents
• Porous burner with alumina saddles stable down to 1.1 vol%CH4
(Wood et al., 2009; Env. Sci. Technol. 43: 9329-9334)
8. OUTLOOK AND CHALLENGES
(Van der Ha et al., 2010; Appl. Env. Microbiol. 87: 2355-2363; LabMET)
1. Diffuse methane emissions from storage and effluents
Effluent AD
Algal culture +
Methanotrophic bacteria
No diffuse methane emissions
Biomass with added value as:• Protein• Oil (PHB/ PHA)• PUFA• Antibiotics
• Algae – Methanotroph co-cultures
8. OUTLOOK AND CHALLENGES
2. Biogas desulphurization
Desulphurization coupled to lithotrophic denitrifcation
BiogasScrubbing with activated sludge
Biogas free of H2S
S0
To be used as a fungicide
2–4 kg S2- m-3 d-1
EBRT 10 min.
(Basphinar et al. 2011, Process Biochemistry 46:916-922)
!
8. Outlook and challenges
3. Special mixed cultures(Constructed consortia) :*Cellulose degraders and methanogens on cassava
residues (Zhang et al. 2011; Biores. Techn. 102: 8899-8906)
* Methanosarcina + Clostridium butyricum to produce both Biogas and 1,3 Propane Diol from methanolic glycerol in the biodiesel
factory (Bizukoje et al. 2010 ; Bioprocess Biosyst.Eng. 33:507-523 )
54
8.Outlook and challenges 4.Chain elongation of fatty acids & ethanol
*Ethanol+ Acetate Become hydrophobic LCFA (n-caproic )
Bv : Several kg /m3.d *Harvest by -Acidification and flotation -In line membrane extraction *Use as :Feed additive/Green antimicrobials/Fuel *The microbiome consists of Clostridium /
Bifidobacterium / Desulfitobacterium sp…(Agler et al. 2012; EST DOI 10.1039) (Steinbusch et al.2011; En. Env.Sci 4: 216-224)
A. Chemical Potato factory
Colsen process Plant-derivedMoerman process struvite
Sewage treatment plant
about 0.5 kg crude struvite per IE per year (Wallaeys Plant, Belgium)
NuReSys:
high quality MAP
8. OUTLOOK AND CHALLENGES
(Shu et al., 2006; Bioresource Technol. 97: 2211-2216)
5. Advanced recovery of phosphate
B. Biological: The ureolytic bio-catalytic process
+ The process removes down to 2 mg PO43-- P/L
+ The cost is competitive with Fe3+
(Carballa et al., 2009; J. Chem. Technol. Biotechnol. 84: 63-68; LabMET)
8. OUTLOOK AND CHALLENGES
5. Advanced recovery of phosphate
Mg NH4 PO4
(struvite)
AD EffluentUrea
MgO/MgCl2
Agriculture must ‘certify’ the ‘Natural Stable Fertilizers .
8. OUTLOOK AND CHALLENGES
6. Advanced recovery of nitrogen
Dry organic
fertilizer
Mechanical Vapor Recompression
(MVR)
Steamstripping
+ MVR
Anaerobic digestion and combustion – The Nitrogen case
After Udert & Waechter, 2012, Wat. Res. 26: 453-464
Manure at 4 kg N/ m³
Anaerobic digestionBiogas
Partial nitrificationNH4
+ →NH4NO3
MF/IO to 20% volume
80% 20%
Ion Exchange Distillation with vapor compression
WaterSolid residue with some 25% NH4NO3
Cofuel ?
Costs to remove 1 kg N
0 €
0,1 €
1,0 €
3,75 €
∑ 5,0 €
Calorific value per kg N ≈ 1,0 €
Netto cost≈ 4,0 € per kg N
Netto cost in case of conventional N/DN: 4-5 €/kg N
8. OUTLOOK AND CHALLENGES
7..Boosters ‘all-in-one’ dosed at 5% of Bv
*Steady multi e-acceptor *All round bio-available macro & micro nutrients ( Ni, Co , W !....) (Jiang et al. 2012 Renewable Energy 44:206-214)
*Cross inoculum ( new genes )
*Calcium binder for LCFA (Kleybocker et al. 2012 ; Waste Management 32: 1122-1130) ( Zhang et al. 2011; J .Chem.Technol. 86: 282-289)
Anaerobic Digestion can profit from clever additives
8. OUTLOOK AND CHALLENGES
8. Life Cycle Analysis (LCA)
Comparisment of the LCA-data for the treatment of industrial wastewaters:
1. AD2. MFC3. MEC (with recovery of H2O,…)
Results: 1 ≈ 2 < 3
Yet: AD can be empowered with plenty extra recoveries !
(Foley et al., 2010; Env. Sci. Technol. 44: 3624-3637)
Anaerobic Digestion is top noth sustainable
9. 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 biomassHumus + 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)
8. OUTLOOK AND CHALLENGES
9. OUT OF THE BOX
GMO methanogens e.g. ● Low sensitivity to NH3, H2S, salt
● Improved mixotrophic growth
Industrial production of SAO + mixotrophic Methanosarcina
Production of ‘all round booster inocula’(cfr. dried yeast)
CODClean biogas
Use on the farm the biogas to produce pre/pro biotics for animal husbandry
9. OUT OF THE BOX
Nano-metals to enhance H2-transfer
H2
e.g. BioPd
(De Windt et al., 2005; Environ. Microbiol. 7, 314-325; LabMET).
Fermentative bacteria MethanogensSugar
9. OUT OF THE BOX
*High conductivities(≥ 30 mS cm-1)
Electrodialysis
Salts + NH4+ Organics
Better digestibility
(3 € m-3)
!
* OTHER NITROGEN REMOVAL TO IMPROVE AD
1.AIR STRIPPING 2.ION EXCHANGE/ADSORBANTS3.REVERSE OSMOSIS4.MFC5……PROGRESS IS MORE THAN WELCOME
The brine can stripped and the NH3 adsorbed (Desloovere et al . 2012; LabMET )
10. CONCLUSIONS