1

Problems at the biogas plant

Henrik Bangsø NielsenBiogasforum, seminar, 29/11-2005

2

Strategy and objectives

Data obtained from Danish biogas plants

On going experiments

Future experiments

Comments from the audience

Outline

3

Danish centralized biogas plants

Lemvig biogas plant

Animal manure 362 t/day

Alternative biomass: 75 t/day

Biogas production 51,6 m3/m3

Temperature 53oC

Reactor capacity 7600 m3

HRT 18 days

Post storage 18oC/ 3d

(Al Seadi, 2000)

(Biogasforum)

4

Strategies and objectives

2001 status*: 1,5% of the production is lost via imbalances andtechnical problems, but what about suboptimal performances?

The project mainly focuses on the microbiology of the process

Research along with practical ”real life” experiences

*Planenergi, Midtjylland 2001: Årsager til hæmning af biogasprocessen

Visits at biogasplants

Data collection

Experiments and resultsthat can be 1) directly related and used by specific plants and 2) can

be published

A B

C

5

H2, CO2 Acetate

VFA, Lactate, Alcohols

Biological polymersCarbohydrates, lipids, proteins

Mono- andoligomers

CH4 , H2O CH4 , H2O

Fermentative bacteria

Syntrophic bacteria

H2-consumingmethanogens

Aceticlastic methanogens

Hydrolytic extracellular

enzymes

Acetate oxidizingbacteria

Homo-acetogenicbacteria

The biogas process

6

Visits at biogas plants

Main conclusions:

“No problems”

Pre-storage tanks are not useful

Substrate composition is unknown

Substrate degradation characteristics is unknown

Inadequate surveillance, especially with regard to VFA

7

Process breakdown

BlåbjergLCFA-inhibition

0,0

0,5

1,0

1,5

2,0

2,5

16-10-2001

15-12-2001

13-02-2002

14-04-2002

13-06-2002

12-08-2002

11-10-2002

10-12-2002

08-02-2003

09-04-2003

08-06-2003

07-08-2003

06-10-2003

05-12-2003

03-02-2004

03-04-2004

02-06-2004

01-08-2004

30-09-2004

29-11-2004

28-01-2005

29-03-2005

date

me

tha

ne

(m

3/m

3 r

ea

cto

r v

ol.

)

8

0

0,5

1

1,5

2

2,5

15-06-1994

28-10-1995

11-03-1997

24-07-1998

06-12-1999

19-04-2001

01-09-2002

14-01-2004

28-05-2005

10-10-2006

Date

m3

/(m

3 r

ea

cto

r v

ol.

)

Process breakdown

9

0

0,5

1

1,5

2

2,5

24-07-1998 06-12-1999 19-04-2001 01-09-2002 14-01-2004 28-05-2005 10-10-2006

Date

m3/

(m3

reac

tor

vol.)

Biogas production

Ammonia inhibition frompigmanure og mucosa

Process breakdown

10

0

0,5

1

1,5

2

2,5

24-07-1998 06-12-1999 19-04-2001 01-09-2002 14-01-2004 28-05-2005 10-10-2006

Date

m3

/(m

3 r

ea

cto

r v

ol.

)

Biogas production

Suboptimal reactor performance

+-

11

0

0,5

1

1,5

2

2,5

24-07-1998 06-12-1999 19-04-2001 01-09-2002 14-01-2004 28-05-2005 10-10-2006

Date

m3

/(m

3 r

ea

cto

r v

ol.

)

0

200

400

600

800

1000

1200

ton

s

Biogas production Total fedt

Suboptimal reactor performance

12

0

0,5

1

1,5

2

2,5

24-07-1998 06-12-1999 19-04-2001 01-09-2002 14-01-2004 28-05-2005 10-10-2006

Date

m3

/(m

3 r

ea

cto

r v

ol.

)

0

200

400

600

800

1000

1200

Fe

dt

ton

s

Biogas production Total fedt Daka fedt

Fra 1/11-04 sker der et skifte frakogt madaffald til Daka-fedtaffald.

Suboptimal reactor performance

13

Case story:

Whey replaced with blood from pigs at the 1. of September 2005

Slow inhibition of biogasproduction observed in thebeginning of October

Biogas production constitutedonly 40% of normal productionat the 8. November

Propionate extremely high

Biogas production

0

0,5

1

1,5

2

2,5

3

3,5

4

06-okt-05 13-okt-05 20-okt-05 27-okt-05 03-nov-05

10-nov-05

17-nov-05

24-nov-05

m3/

(m3

reac

tor

vol.)

date

0

20

40

60

80

09-nov-05 14-nov-05 19-nov-05 24-nov-05

mM

Acetat Propionate Isobut. Butyrate Isoval. Valerate

VFA

date

Suboptimal reactor performance/breakdown

14

Total ammonia, NH3 and pH

0,00,51,01,52,02,53,03,54,04,5

06-okt 13-okt 20-okt 27-okt 03-nov 10-nov 17-nov 24-nov

date

NH

3

8,0

8,2

8,4

8,6

8,8

9,0

pH

Suboptimal reactor performance/breakdown

Reasons for inhibition:

Combination of increasing pH andincreasing ammonia concentration

Increase in ammonia concentrationwas related to the feeding with pigblood

Increase in pH was caused by theincrease in ammonia and omissionof whey from the feedstock

Construction of the plant forcedthe operator to add further amounts of blood even after theimbalance had occurred

Inadequate measurement of VFA

Free ammonia fraction at different temp.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

6 7 8 9pH

NH

3 / t

ota

l am

monia

37

53

70

90

(Figure by Hinrich Hartmann)

15

0

0,5

1

1,5

2

2,5

3

3,5

29-08-2002

28-10-2002

27-12-2002

25-02-2003

26-04-2003

25-06-2003

24-08-2003

23-10-2003

22-12-2003

20-02-2004

20-04-2004

19-06-2004

18-08-2004

17-10-2004

16-12-2004

14-02-2005

15-04-2005

14-06-2005

date

met

han

e (m

3/m

3 re

acto

r vo

l.)

Studsgaard biogas plant

16

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

29-08-2002

28-10-2002

27-12-2002

25-02-2003

26-04-2003

25-06-2003

24-08-2003

23-10-2003

22-12-2003

20-02-2004

20-04-2004

19-06-2004

18-08-2004

17-10-2004

16-12-2004

14-02-2005

15-04-2005

date

met

han

e (m

3/m

3 re

acto

r vo

l.)

daily

10 per. Mov. Avg. (daily)

20 per. Mov. Avg. (daily)

Suboptimal conditions

Foaming starts april 2003 Foaming ends march 2005

17

y = - 0,0001x + 7,6639

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

13-07-2002

01-09-2002

21-10-2002

10-12-2002

29-01-2003

20-03-2003

09-05-2003

28-06-2003

me

tha

ne

(m

3/m

3 r

ea

cto

r v

ol.)

y = - 0,0009x + 36,725

0,00

0,50

1,00

1,50

2,00

2,50

3,00

3,50

10-12-2002 28-06-2003 14-01-2004 01-08-2004 17-02-2005 05-09-2005

me

tha

ne

(m

3/m

3 r

ea

cto

r v

ol.)

Suboptimal conditions

18

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

01-05-2002

30-06-2002

29-08-2002

28-10-2002

27-12-2002

25-02-2003

26-04-2003

25-06-2003

24-08-2003

23-10-2003

22-12-2003

20-02-2004

20-04-2004

19-06-2004

18-08-2004

17-10-2004

16-12-2004

14-02-2005

15-04-2005

date

me

tha

ne

(m

3/m

3 r

ea

cto

r v

ol.

)

daily

10 per. Mov. Avg. (daily)

20 per. Mov. Avg. (daily)

Sinding-ørre biogas plant

19

Screening of various wastes in batch experimentsToxicityBiogas potentialWaste index

Tests of the most inhibitory compounds in reactor experiments

Effect on microbial activityEffect on microbial composition (DNA extraction and TGGE)Maximum loading rateIdentification of suitable parameters for indication of process imbalances (VFA, Methane….)

On going experiments related to full-scale experiences

20 Screening of various wastes in batch experiments with regard to toxicity and biogas potential

Lipids

Meat and bone meal

Mixture

-400

-200

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60

time (days)

me

tha

ne

pro

du

cti

on

(m

l/g

VS

)

-400

-200

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60

time (days)

me

tha

ne

pro

du

cti

on

(m

l/g

VS

)

-400

-200

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60

time (days)

me

tha

ne

pro

du

cti

on

(m

l/g

VS

)

-400

-200

0

200

400

600

800

1000

1200

1400

0 10 20 30 40 50 60

time (days)

me

tha

ne

pro

du

cti

on

(m

l/g

VS

)

1.0 gVS/l

5.0 gVS/l

2.0 gVS/l

10 g/lVS

21

Waste type Temperature Inhibition level

g VS/l = kg VS/tBlood from pigs 37oC 0,5-1,0

Blood from pigs 55oC <0,5

Shrimp sludge 37oC 1,0-5,0

Shrimp sludge 55oC 0,5-1,0

Meat and Bone meal 37oC 1,0-5,0

Meat and Bone meal 55oC 0,5-2,0

100% Fat, DAO 55oC <1,0

Flotations fedt, pigs 55oC 0,5-1,0

Bakery (mainly fat) 55oC 5,0-10,0

Flotationsfedt, pigs 55oC 5,0-10,0

Flotationsfedt, pigs 55oC 5,0-10,0

Limfedt (fat) 55oC 5,0-10,0

Food waste (fat) 55oC >10,0

Flotationsfedt, chickens

55oC >10,0

Waste index. Examples

22

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

165 170 175 180 185 190 195 200 205

time (days)

met

hane

yie

ld (m

l/gV

S)

Effect of MBM pulses

5 gVS/l 5 gVS/l 5 gVS/l

Inadequate process surveillance

23

Effect of MBM pulses

Acetate

Propionate

Isovalerate

Isobutyrate

Butyrate

Valerate

VFA dynamics

0

10

20

30

40

50

165 170 175 180 185 190 195 200 205

time (days)V

FA (m

M)

0

2

4

6

8

10

12

165 170 175 180 185 190 195 200 205

time (days)

VF

A (

mM

)

24

Recovery of reactors following process imbalances:DilutionRe-inoculationContinued feeding with wasteFeeding with manure onlyNo feeding at all

Foaming in biogas plantsMicrobial phenomenon?Physical phenomenon?

Future experiments related to full-scale experiences

25

Conclusions

?

26

Acknowledgements

Thanks to Henard Meer de Soto and Elena Pueyo Abad for sharing their resultsThanks to Hector Garcia and Prasad L. Kaparaju for their technical assistanceThe work is supported by Energistyrelsens Energiforsknings-program (EFP-2005)

Thank you for your attention!!!!