ANAEROBID DIGESTION IN FULL EVOLUTION W. VERSTRAETE Lab. Microbial Ecology and Technology (LabMET)...

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