Impact of different pretreatments

on the anaerobic digestion of

household waste organics

Bruno Mattheeuws, V Baltic Biogas Forum 2016, Gdansk

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OWS: THE COMPANY

• Developer and owner of DRANCO technology: dry

continuous digestion technology developed in early

80’s

• OWS created in 1988: >25 years experience in

anaerobic digestion of household waste organics or

equivalent

• Sales: average 15 million €/y

since 2010

• 75 people

• >90% export

• Main office located in Ghent (Belgium)

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GHENT, BELGIUM

- #3 most authentic destination (National Geographic Traveler Magazine)

- #7 must-visit (Lonely Planet)

Ordinary morning in medieval city center

One of many Ghent city festivals

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1. BRECHT I (Belgium) 1992 20 000 tpy Biowaste+

2. SALZBURG (Austria) 1993 20 000 tpy Biowaste

3. BASSUM (Germany) 1997 105 000 tpy Residual waste

4. AARBERG (Switzerland) 1998 11 000 tpy Biowaste

5. KAISERSLAUTERN (Germany) 1999 25 000 tpy Residual waste

6. VILLENEUVE (Switzerland) 1999 10 000 tpy Biowaste

7. BRECHT II (Belgium) 2000 50 000 tpy Biowaste+

8. ROME (Italy) 2003 40 000 tpy Mixed waste

9. LEONBERG (Germany) 2004 30 000 tpy Biowaste

10. PUSAN (South Korea) 2005 70 000 tpy Biowaste

11. HILLE (Germany) 2005 100 000 tpy Residual waste+ sludge

12. MÜNSTER (Germany) 2005 80 000 tpy Residual waste

13. TERRASSA (Spain) 2006 25 000 tpy Biowaste

14. VITORIA (Spain) 2007 120 000 tpy Mixed waste

15. HOTAKA (Japan) 2008 3 000 tpy Biowaste+

16. ALICANTE (Spain) 2008 180 000 tpy Mixed waste

17. TENNEVILLE (Belgium) 2008 39 000 tpy Biowaste

18. SEOUL (South Korea) 2009 30 000 tpy Biowaste

19. KEMPTEN (Germany) 2009 18 000 tpy Biowaste

20. LESZNO (Poland) 2010 50 000 tpy Mixed waste

21. HENGELO (The Netherlands) 2011 50 000 tpy Biowaste

22. MIRANDELA (Portugal) 2012 55 000 tpy Mixed waste

23. WIJSTER (The Netherlands) 2012 57 000 tpy Residual waste

24. WIJSTER (The Netherlands) 2013 40 000 tpy Biowaste

25. BOURG-EN-BRESSE (France) 2015 66 000 tpy Mixed waste

26. CHAGNY (France) 2015 73 000 tpy Mixed waste

27. NORTH YORKSHIRE (UK) 2017 40 000 tpy Residual waste

28. NÜSTEDT (Germany) 2006 20 000 tpy Energy crops

29. LANGENDORF (Germany) 2010 Wet post-digester

BIOGAS PLANT REFERENCES

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EXPERIENCE WITH DIFFERENT PRETREATMENTS

1. High-pressure press

2. Short residence rotating drum followed by shredder and

screening

3. Long residence rotating drum followed by screening

4. Shredder followed by screen

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1. HIGH-PRESSURE PRESS: KAISERSLAUTERN

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1. HIGH-PRESSURE PRESS: KAISERSLAUTERN

70.000 t

PRESS

Wet fraction: 27.500 t

~ 40%

AD

Dry fraction: 42.500 t

~ 60%

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1. HIGH-PRESSURE PRESS

• VM-Press / OREX / OEP / …

• Installed in DRANCO-plant in Kaiserslautern

(Germany) since 2006

• First MSW, then source separated organics (SSO)

• Waste is squeezed in special extrusion chambers

fitted with holes (20mm) in the external surface

– Wet fraction squeezed out of the extrusion chambers is sent

to dry AD

– ‘overflow’ = dry fraction = RDF

Consists of the pressure

resistant components of the

waste, such as plastics,

wood, paper & cardboard

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1. HIGH-PRESSURE PRESS: EXPERIENCES IN KSL

• Current feedstock: SSO

• No shredding => compost with lower contamination

• About 40% by weight to wet fraction, 60% to dry fraction

=> small amount to wet fraction

(↔ 85-90% in Brecht (case 2-, comparable feedstock, also no shredding)

• wet fraction:

– TS: ~ 30%

– Biogas potential: 80-135 Nm³/ton (average 110 Nm³/ton)

• dry fraction:

– TS: ~ 40%

– still contains > digestible organic material (biogas potential

loss!)

– Up to 100 Nm³ biogas/ton

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1. HIGH-PRESSURE PRESS: EXPERIENCES

• << biological loading rate AD after installing the high-

pressure press (↔ previously utilized ball mill)

• Relatively low recovery of organic fraction

• 50% of biogas in dry fraction (not valorized)

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2. SHORT RESIDENCE TIME ROTATING DRUM: BRECHT

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WASTE DRANCO PLANT BRECHT

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2. SHORT RESIDENCE TIME ROTATING DRUM

• Comminuting drum (short residence time, ± 3 hrs)

• Installed in DRANCO-plant in Brecht (BE) since 2000

• Feedstock: SSO

• Drums appeared as a first processing step in the 80s – Drums use gravity to tumble, mix, break down & homogenize waste

(~ friction)

– Dimensions: Ø 3 m, length 16m

• Main purpose: selective comminution of the waste – organic fraction is comminuted

– inert fraction remains quite the same

– paper & cardboard are also partly

comminuted

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2. SHORT RESIDENCE TIME ROTATING DRUM

• Degree of filling: ~ 50%

• Screening 40mm

– <40mm => AD

– >40 mm: shredder (slow turning screw type mill

& 2nd drum

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FLOW DRANCO PLANT BRECHT

SHREDDER

DRANCO

DIGESTER

Digestate

GAS

STORAGE

FLARE

GAS ENGINES

Biogas

Polymer

solution

> 250 mm

PUSHING

FLOOR

SHREDDER

COMMINUTING

DRUM

MAGNET

COMMINUTING

DRUM

DOSING UNITMIXING UNIT /

FEEDING PUMP

Rejects

ROTATING

SIEVE

BIOWASTE

ROTATING

SIEVE

> 40 mm

STEAM

GENERATOR

Steam

CENTRIFUGE

Rejects

Effluent to wastewater

treatment plant

< 40 mm

Exhaust

gases

MIXING UNIT

PRESSVIBRATING

SIEVE

PRESS WATER

TANK

AEROBIC

MATURATION

Electricity

Compost

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2. SHORT R-TIME ROTATING DRUM: EXPERIENCES

• Shredder: slow turning screw type mill (“minimisation

rolls”)

• Production of clean compost:

– Plastics are not shredded but left in large strands

– Glass is not splintered but will stay hole or breaks into

larger pieces

– Textiles are not reduced into small pieces but are torn

open

=> These items can be removed by screening (before

or after AD/composting)

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2. SHORT R-TIME ROTATING DRUM: EXPERIENCES

• Soiled paper & other digestible organics are reduced

in size and go to the AD

• Plant has been running for >14 years

• Production of high-quality compost

• Large fraction to anaerobic digestion

(85-90% in Brecht after 2 comminuting drums)

• Biogas production: 95-145 Nm³/t (average of 120 Nm³

per ton during last 10 years)

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3. LONG R-TIME ROTATING DRUM: BOURG-EN-BRESSE

Short residence rotating drum followed

by shredder and screening

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MIXED WASTE DRANCO PLANT BOURG-EN-BRESSE

Short residence rotating drum followed

by shredder and screening

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3. LONG R-TIME ROTATING DRUM: BOURG-EN-BRESSE

• Comminuting drum (slowly rotating, long residence time)

• Installed in DRANCO-plant in B-E-B (FR) since 2015

• Dimensions: Ø 4,25m, length 40m

• Residence time: ± 2,5 days

• Degree of filling: 75%

• Fraction <50mm to digester

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FLOW DRANCO PLANT BOURG-EN-BRESSE

Mixed waste

2 COMMINUTING

DRUMS

Biogas

MIXER/

FEEDING PUMP

DRANCO

DIGESTER

Residue

Steam Process

waterFeCl2

RDF

SORDISEP

Inerts

Process water

Polymers Anti-foam

Centrifuge

cake

OVERBAND

MAGNET

NON-FERRO

SEPARATOR

High calorific

fraction

Process water

Low calorific

fraction

ION

COMPOSTING Green waste

INTENSIVE

MATURATION

POST-

MATURATION

Compost

High calorific

fractionGAS STORAGE

FLARE

Electricity

STEAM

GENERATORSteam

GAS

ENGINES

DRUM SCREEN

200 MM

50 MMDRUM SCREEN

OVERBAND

BALLISTIC

SEPARATOR

DOSING UNIT

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• After drums: further pretreatment (screens, magnet,

ballistic, …)

• To digester: <2 inch

– 7,7 % impurities

– TS: 47,5%

– VS: 73,0%

– Biogas production: 140 Nm³/ton (125-160 Nm³/ton)

3. LONG R-TIME ROTATING DRUM BOURG-EN-BRESSE

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4. SHREDDER FOLLOWED BY SCREEN: TENNEVILLE

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FLOW DRANCO PLANT TENNEVILLE

SHREDDER 1

ROTATING

SIEVE (60 mm)

MAGNET

MAGNET

SHREDDER 2

DOSING UNIT FEEDING

PUMP

GAS STORAGE

STEAM

GENERATOR

Mixing

DRANCO

DIGESTER

3.150 m³

Biowaste

(& pasty waste)

Residue

FLARE

< 40

40 - 150

Rejects

Electricity GAS

ENGINES

Liquid waste streams

Bulking material

+ Yard waste

(>20 mm)

Composting

Preshredded

yard waste (<20 mm)

Sludge dryer

Water treatment plant

Heat

DOSING

SCREW

>150

Biogas

Steam

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4. SHREDDER FOLLOWED BY SCREEN: EXPERIENCES

• Simple configuration

• Low space requirement

• Quick run-through, no waste in equipment at night

• Advantage: “low amount of overflow”

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4. SHREDDER FOLLOWED BY SCREEN: HENGELO

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SCREEN FOLLOWED BY SHREDDER

• Screen 3 fractions (0mm < 60mm < 150mm < ….)

• Installed in DRANCO-plant in Hengelo (NL) since

2011

• SouFeedstock: SSO

• Existing pretreatment (< DRANCO)

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• Capacity:

– 50.000 tpy

• 40.000 tpy biowaste

• 5.000 tpy overdue products

• 5.000 tpy liquid products

• Digester volume: 3.450 m³

• Start-up: 2011

• Digestate is mixed with fraction 60-160 mm

=> dewatering is avoided

• Biogas production

– 100% gas engines (2 x 1,2 MW)

– Heat is used in district heating network

SCREEN FOLLOWED BY SHREDDER

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FLOW DRANCO PLANT HENGELO

SHREDDER

DRANCO

DIGESTER

Digestate

GAS

STORAGE

FLARE

COOLING

Biogas

Steam

DOSING

UNIT

SHREDDERSTAR SCREEN

60-150 mm

DOSING UNITMIXING UNIT /

FEEDING PUMP

BIOWASTE

> 150 mm

BIOGAS

ENGINES

Liquid organic

waste

PRESS

COMPOSTING

Electricity

MAGNET

< 60 mm

STORAGE TANK

Heat

MIXING60-150 mm

Compost

BOILER

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SCREEN FOLLOWED BY SHREDDER: EXPERIENCES

• Perfect pretreatment for source separated biowaste:

– Simple & cheap

– Low overflow

– Good compost quality

• Biogas production < expectations in this plant

– BMP on different fractions

– <10mm lowers the biogas production (mainly sand) (<3 mm!)

– 0-10mm = 1/3 of volume (but <<<< biogas + tear &

wear)

– Removing 0-3 mm would result in 15% more biogas

– Decision: remove 0-10mm (out of the 0-60mm)

• 0-10mm: bypass digestion

• Extra star screen installed

=> positive impact on biogas production!

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OVERVIEW

%

RECOVERY

C/N LOADING

RATE COST REMARKS

HIGH-PRESSURE

PRESS

KAISERSLAUTERN 40% Low

Low CAPEX

High OPEX

Crushing glass?

Recycling of dry

fractions?

HIGH-SPEED

REDUCTION DRUM

BRECHT 85-90% High

Low CAPEX

Low OPEX

Efficient removal

of plastics

SHREDDER &

SCREEN

IDELUX Up to 95% High

Low CAPEX

Medium OPEX Mainly for SSO

LOW-SPEED

REDUCTION DRUM

BOURG-EN-BRESSE

60%

(80% SSO) High

High CAPEX

Low OPEX

Efficient removal

of inorganics

(more for MSW)

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• Main goal of pretreatment & biological treatment (MBT):

reduce the amount of final residue to be disposed

• Size reduction is commonly one of the first

unit operations in pretreatment & MBT processes

• For production of low contamination compost

– From MSW:

• Excellent collection of hazardous waste

• Avoid to shred the feedstock (use drums or press)

• Efficient metal separation in the plant

• (Optional wet post-separation)

CONCLUSIONS

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• For production of low contamination compost

– From source separated biowaste:

• (soft) shredding as a first or 2nd step

– Simple & cheap

– Limited amount of overflow

• Type of pretreatment has an influence on the (choice of)

AD-technology

– High pressure press: wet fraction of SSO too wet for

dry AD?

– Dry AD: ideal with reduction drums and shredder +

sieve

CONCLUSIONS

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DEVELOPMENT OF AD OF MSW IN GERMANY

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DZIĘKUJĘ ZA UWAGĘ!