ANAEROBIC CO ANAEROBIC CO-DIGESTION OF CHICKEN ...
ANAEROBIC COCO-DIGESTION OF CHICKEN MANURE IN LABORATORYLABORATORY- AND PILOTPILOTSCALE BATCH REACTORS – METHANE PRODUCTION AND AND QUALITY OF DIGESTATE DIGESTATE Luste, Sami & Soininen, Hanne Mikkeli University of Applied Sciences, Finland, E-mail [email protected]
INTRO INTRODUCTION This study was conducted to evaluate: • The feasibility of high nitrogen content chicken manure in mixture with cattle slurry and vegetable wastes for the biogas production. • The effect of longer digestion period on hygienic quality of digestate. • The differences between the laboratory scale batch reactor (LSBR LSBR) PSBR). LSBR and pilot scale batch reactor (PSBR PSBR
Size and mixing techniques was the main differences between the LSBR (1,0 l; manual; ~ once a day) and the PSBR (2,7 m ; mechanical, continuous). 3
Table 3: 3: Methane production potentials, VS removal from the batches and characteristics of the digestates.
LSBR
PSBR
LSBR inocolumn
Biogas (m 3/t VS added ) Methane (m 3/t VS added )
290 80
490 290
80 21
MATERIALS AND METHODS Both of the batches digested the mixture of chicken manure, cattle slurry and vegetable wastes at 35 ⁰C mixed according to the average production ratios in the region of South-Savo (5:30:1; wet weight, w.w; Table 1).
CH 4 (%) TS (%) VS (%) VS-removal from batches Ntot (mg/g) Nsol (mg/g)
Table 1: Characteristics of the materials & inocolum. Cattle Chicken Vegetable slurry manure waste
NH 4-N+ (mg/g) Conductivity (mS/cm) Enterobacteria (cfu/g) Clostridis (cfu/g) pH
< 3–70 5.1 3.6 41 3.9 3.0 2.5 5.1 < 10 1000 8.2
40-70 5.2 3.9 35 3.9 2.5 1.8 1.0 < 100 3500 8.1
< 3 –30 4.9 3.9 11 3.6 3.6 1.8 0.8 < 10 1000 8.2
TS (%) VS (%) pH Ntot (mg/g) Nsol (mg/g) NH4-N+ (mg/g) Enterobacteria (CFU/g) Clostrids (CFU/g)
Inoculum
7.0 - 8.3 5.8 - 6.6 6.8 - 7.8 3
21 - 24 14 - 17 7.8 - 8.2 15
3.2- 3.8 3.0 - 3.3 6.2 - 6.4 0.9
5.2 - 5.6 3.6 - 4.1 7.7 - 8.1 –
1.8
13
0.5
–
1.0 6600 400
10 400 16000
0.3 – –
– 2800 < 100
RESULTS AND CONCLUSION The methane content in biogas increased from the start-up (~20%) up to 70 % (day 21), since re-decreasing to 60 % in PSBR and to < 3% in LSBR (Fig. 1). This was probably because of NH content in LSBR (Table 3) was higher than reported inhibiting levels for methanogens (0.1-0.25 g NH /l; [1, 2]).
•
Chicken manure can be digested in the mixture with cattle slurry and vegetable wastes in a ratio of 5:30:1, w.w, but high nitrogen content may also cause attenuated methane production and lost of fertilizer potential in digestate.
•
Continuous mixing improves degradation of material and microbial operation causing better buffering capacity of the process [3]. It may have also caused nitrogen removal from PSBR via evaporation of NH (Table 3).
3
3
3
) m ( le cas t lo i p ) ? ( s a g io b & ) ? ( 4 H C
60
10,0
3
50
8,0
40 6,0 30 4,0 20 2,0
10 0
0,0 0
10
20
30
40
50
60
70
) (l le ac syr o t ar o b la ) (¦ sa g o i b
•
Longer duration of digestion improved the hygienic quality of digestate. This can be reviewed when 1) post-digested inoculumn are compared to the original (HRT 21 day) and/or 2) hygiene of LSBR with the longer duration of digestion (82 day) is compared to the hygiene level in PSBR (duration of 55 days; Table 1 & 2).
& ) ¦( 4 H C
80
Days
Figure Figure 1: Cumulative methane and biogas production from PSBR (55 days) and from LSBR (82 days).
[1] Callaghan F. J., Wase D. A. J., Thayanithy K., Forster C. F. (2002): Continuous codigestion of cattle slurry with fruit and vegetable wastes and chicken manure Biomass Bioen. 22: 71-77. [2] Bujoczek G., Oleszkiewicz J., Sparling R., Cenkowski S. (2000): High Solid Anaerobic Digestion of Chicken Manure. J. Agricult. Eng. Res. 76: 51-60. [3] Mata-Alvarez J. (2003): Biomethanization of the organic fraction of municipal solid wastes, 2nd ed., IWA, London, Great Britain
The present study is part of the “ESBIO – energy self-sufficient farm -project” in eastern Finland.
INTRO INTRODUCTION This study was conducted to evaluate: • The feasibility of high nitrogen content chicken manure in mixture with cattle slurry and vegetable wastes for the biogas production. • The effect of longer digestion period on hygienic quality of digestate. • The differences between the laboratory scale batch reactor (LSBR LSBR) PSBR). LSBR and pilot scale batch reactor (PSBR PSBR
Size and mixing techniques was the main differences between the LSBR (1,0 l; manual; ~ once a day) and the PSBR (2,7 m ; mechanical, continuous). 3
Table 3: 3: Methane production potentials, VS removal from the batches and characteristics of the digestates.
LSBR
PSBR
LSBR inocolumn
Biogas (m 3/t VS added ) Methane (m 3/t VS added )
290 80
490 290
80 21
MATERIALS AND METHODS Both of the batches digested the mixture of chicken manure, cattle slurry and vegetable wastes at 35 ⁰C mixed according to the average production ratios in the region of South-Savo (5:30:1; wet weight, w.w; Table 1).
CH 4 (%) TS (%) VS (%) VS-removal from batches Ntot (mg/g) Nsol (mg/g)
Table 1: Characteristics of the materials & inocolum. Cattle Chicken Vegetable slurry manure waste
NH 4-N+ (mg/g) Conductivity (mS/cm) Enterobacteria (cfu/g) Clostridis (cfu/g) pH
< 3–70 5.1 3.6 41 3.9 3.0 2.5 5.1 < 10 1000 8.2
40-70 5.2 3.9 35 3.9 2.5 1.8 1.0 < 100 3500 8.1
< 3 –30 4.9 3.9 11 3.6 3.6 1.8 0.8 < 10 1000 8.2
TS (%) VS (%) pH Ntot (mg/g) Nsol (mg/g) NH4-N+ (mg/g) Enterobacteria (CFU/g) Clostrids (CFU/g)
Inoculum
7.0 - 8.3 5.8 - 6.6 6.8 - 7.8 3
21 - 24 14 - 17 7.8 - 8.2 15
3.2- 3.8 3.0 - 3.3 6.2 - 6.4 0.9
5.2 - 5.6 3.6 - 4.1 7.7 - 8.1 –
1.8
13
0.5
–
1.0 6600 400
10 400 16000
0.3 – –
– 2800 < 100
RESULTS AND CONCLUSION The methane content in biogas increased from the start-up (~20%) up to 70 % (day 21), since re-decreasing to 60 % in PSBR and to < 3% in LSBR (Fig. 1). This was probably because of NH content in LSBR (Table 3) was higher than reported inhibiting levels for methanogens (0.1-0.25 g NH /l; [1, 2]).
•
Chicken manure can be digested in the mixture with cattle slurry and vegetable wastes in a ratio of 5:30:1, w.w, but high nitrogen content may also cause attenuated methane production and lost of fertilizer potential in digestate.
•
Continuous mixing improves degradation of material and microbial operation causing better buffering capacity of the process [3]. It may have also caused nitrogen removal from PSBR via evaporation of NH (Table 3).
3
3
3
) m ( le cas t lo i p ) ? ( s a g io b & ) ? ( 4 H C
60
10,0
3
50
8,0
40 6,0 30 4,0 20 2,0
10 0
0,0 0
10
20
30
40
50
60
70
) (l le ac syr o t ar o b la ) (¦ sa g o i b
•
Longer duration of digestion improved the hygienic quality of digestate. This can be reviewed when 1) post-digested inoculumn are compared to the original (HRT 21 day) and/or 2) hygiene of LSBR with the longer duration of digestion (82 day) is compared to the hygiene level in PSBR (duration of 55 days; Table 1 & 2).
& ) ¦( 4 H C
80
Days
Figure Figure 1: Cumulative methane and biogas production from PSBR (55 days) and from LSBR (82 days).
[1] Callaghan F. J., Wase D. A. J., Thayanithy K., Forster C. F. (2002): Continuous codigestion of cattle slurry with fruit and vegetable wastes and chicken manure Biomass Bioen. 22: 71-77. [2] Bujoczek G., Oleszkiewicz J., Sparling R., Cenkowski S. (2000): High Solid Anaerobic Digestion of Chicken Manure. J. Agricult. Eng. Res. 76: 51-60. [3] Mata-Alvarez J. (2003): Biomethanization of the organic fraction of municipal solid wastes, 2nd ed., IWA, London, Great Britain
The present study is part of the “ESBIO – energy self-sufficient farm -project” in eastern Finland.
