What digestate is.
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Transcript of What digestate is.
F. Adani, January 24-25F. Adani, January 24-25
What digestate is.F. Adani, A. Schievano, G. D’Imporzano,
F. Tambone, B. Scaglia Di.Pro.Ve.
Università degli Studi di Milano, Via Celoria 2, 20133 Milano
[email protected] website: http://www.diprove.unimi.it/
F. Adani, January 24-25F. Adani, January 24-25
Digestate is not Ingestate
Biological process determines chemical and biological modification of raw
materials (ingestates)
Therefore…………
Anaerobic digestion is a biotechnology
F. Adani, January 24-25F. Adani, January 24-25
Looking for the Identikit!!!!
So… what is digestate ?
? ?
F. Adani, January 24-25F. Adani, January 24-25
Degradation
The AD process affects:
Nutrients
Organic matter quality
Xenobiotics
Organic load
F. Adani, January 24-25F. Adani, January 24-25
Degradation: TS and VS mass balances;
Organic load: BOD5 and COD.
OM quality: biological stability, wet chemical and spectroscopic analyses.
Nutrients: mass balance and speciation.
Xenobiotic content: direct detection.
Our approach
F. Adani, January 24-25F. Adani, January 24-25
OM reduction of 60-70%
DegradationMass balance
100 %
35% ± 10%
0
10
20
30
40
50
60
70
80
90
100
OM
%
Ingestates Digestates
F. Adani, January 24-25F. Adani, January 24-25Abbattimento COD e BOD
Organic load
152 ± 16
68 ± 11
0
20
40
60
80
100
120
140
160
CO
D
gO 2
L-1
Ingestates Digestates
79 ± 10
40 ± 12
0
10
20
30
40
50
60
70
80
BO
D
gO 2
L-1
Ingestates Digestates
COD
BOD
F. Adani, January 24-25F. Adani, January 24-25
OM qualityOM quality
Biological stability OM Biological stability OM degradability degradability Degradation processes determine a
concentration of recalcitrant molecules.
Biological tests
- Anaerobic test;
- Aerobic test.
F. Adani, January 24-25F. Adani, January 24-25
Anaerobic test: potential Anaerobic test: potential biogas productionbiogas production
ABP
0
200
400
600
800
1000
1200
1400
0 10 20 30 40 50 60 70 80 90 100
days
ml
bio
gas
*gT
S-1
It is a good test but it requires time ( 60 dd).
F. Adani, January 24-25F. Adani, January 24-25
Anaerobic test (ABP)
646 ± 76
221 ± 56
0
100
200
300
400
500
600
700
AB
P m
3 bi
ogas
g-1
TS
Ingestates Digestates
F. Adani, January 24-25F. Adani, January 24-25
Aerobic test: liquid state Aerobic test: liquid state respiration indexrespiration index (SOUR) (SOUR)
…..it allows a strong time reduction (20h)
OD Cumulata
0
100
200
300
400
500
600
00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12
tempo prova
OD
Cumulated O2 up-take in 20h
F. Adani, January 24-25F. Adani, January 24-25
Aerobic test
219 ± 60
90 ± 28
0
50
100
150
200
250
OD
20 m
gO2
g-1
TS
Ingestates Digestates
F. Adani, January 24-25F. Adani, January 24-25
y = 2.319x + 73.760
R2 = 0.713
0
200
400
600
800
1000
0 50 100 150 200 250 300 350
OD20 (mgO2 gTS-1)
AB
P (
Nm
L g
TS
-1)
ingestati
digestati
A case study……….
F. Adani, January 24-25F. Adani, January 24-25
Correlation ABP vs SOURCorrelation ABP vs SOUR
R2 = 0.710
0200400600800
10001200140016001800
0 100 200 300 400 500
OD20 (mg O2 gTS)
AB
P (
Nm
L g
TS-1
)
F. Adani, January 24-25F. Adani, January 24-25
Wet analysesWet analyses
Spectroscopic analysesSpectroscopic analyses
OM qualityOM quality
F. Adani, January 24-25F. Adani, January 24-25
CS (%TS)
cell soluble
70-90% 40-70%
OM qualityMacromolecular composition
F. Adani, January 24-25F. Adani, January 24-25
ADL (%TS) (Lignin, cutin,
suberan, sterol)
effetto concentrazione
2-8% 10-35%
OM qualityMacromolecular composition
F. Adani, January 24-25F. Adani, January 24-25
OM qualityCPMAS 13C NMR Spectroscopy
Ingestate
Digestate
F. Adani, January 24-25F. Adani, January 24-25
Pig slurry
Digested Pig slurry
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OM quality
PCA analysis
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OM qualityPCA analysis
IngenstateIngestate
Digestate
Biosolid
Compost
-2.
-1.5
-1.
-.5
.
.5
1.
1.5
-1. -.5 . .5 1. 1.5 2.
Fact.1 63.8%
Fa
ct.2
3
1.9
%
Ingestate
Digestate
Biosolid
Compost
-2.
-1.5
-1.
-.5
.
.5
1.
1.5
-1. -.5 . .5 1. 1.5 2.
Fact.1 63.8%
Fa
ct.2
3
1.9
%
Predig. swinemanure
Freshswinemanure
Biological stability+ -
F. Adani, January 24-25F. Adani, January 24-25
Total N (% TS)
Nutrients: quantity
2-5% 5-12%
F. Adani, January 24-25F. Adani, January 24-25
N-NH4 (% TS)
0-2% 2-8%
Nutrients: quality
F. Adani, January 24-25F. Adani, January 24-25
Organic N
Costante 2-4%
Recalcitrant???
Nutrients: quality
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XenobioticHeavy metals
0.5100.08Cr VI (mg/kg s.s.)
-100.05As (mg/kg s.s.)
-7501.16Cr III (mg/kg s.s.)
500250074.83Zn (mg/kg s.s.)
230100049.58Cu (mg/kg s.s.)
14075018.16Pb (mg/kg s.s.)
10030012.48Ni (mg/kg s.s.)
1.5101.19Hg (mg/kg s.s.)
1.5200.21Cd (mg/kg s.s.)
Compost limits
Bio solid limit
ValueElemento
Example of digestate analysis:
Metal
F. Adani, January 24-25F. Adani, January 24-25
absent
Hygienic parameters
Parameter Digestate Legge 99/92 Reg. CE 1774/02
Fecal coliform (MPN/g TS) 100 10.000 n.i.
Vital Helminthes eggs Absent Absent n.i.
Salmonella Absent < 100 Absent
Escherichia coli Absent n.i. < 1000
n.i. = not indicated
F. Adani, January 24-25F. Adani, January 24-25
Digestate: the Identikit
OM
Low organic load
Medium biological stability
Presence of humus-precursor molecules
Nutrient content
High N content;
High agronomic value.
Xenobiotic content
Very Low
F. Adani, January 24-25F. Adani, January 24-25
Amendment properties
Fertilizer properties
Hygienic product
High quality
Digestate: the Identikit
F. Adani, January 24-25F. Adani, January 24-25
Digestate needs to be qualified……….
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…….… a proposal.… a proposal
Limits needed for:Limits needed for:
Biological stabilityBiological stability Hygienic parametersHygienic parameters Heavy metal contentsHeavy metal contents
1.1. Environmental and human protection:Environmental and human protection:
F. Adani, January 24-25F. Adani, January 24-25
..…. a proposal..…. a proposal
Parameters should be indicated:Parameters should be indicated:
N-tot and N-NHN-tot and N-NH44;; P;P; K;K; OM.OM. Moisture contentMoisture content
2.2. Agronomic use: Agronomic use:
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Thank you Thank you Dipartimento di Produzione Dipartimento di Produzione
VegetaleVegetale Università degli Studi di MilanoUniversità degli Studi di Milano