Transcript Diapositiva 1

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 24-25
Anaerobic digestion
is a biotechnology
Biological process determines chemical and
biological modification of raw materials
(ingestates)
Therefore…………
Digestate is not Ingestate
F. Adani, January 24-25
So… what is digestate ?
?
?
Looking for the Identikit!!!!
F. Adani, January 24-25
The AD process affects:
Degradation
Organic load
Organic matter
quality
Nutrients
Xenobiotics
F. Adani, January 24-25
Our approach
 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.
F. Adani, January 24-25
Degradation
Mass balance
100
90
80
100 %
OM %
70
60
50
40
30
35% ± 10 %
20
10
0
Ingestates
Digestates
OM reduction of 60-70%
F. Adani, January 24-25
Organic load
COD
160
COD gO2 L
-1
140
120
152 ± 16
100
80
60
68 ± 11
40
20
0
Ingestates
Digestates
BOD
80
BOD gO2 L
-1
70
60
79 ± 10
50
40
30
40 ± 12
20
10
0
Ingestates
Digestates
Abbattimento
COD
e BOD
F. Adani, January 24-25
OM quality
 Biological
stability
OM degradability
Degradation processes determine a
concentration of recalcitrant molecules.
Biological tests
- Anaerobic test;
- Aerobic test.
F. Adani, January 24-25
Anaerobic test: potential biogas
production
ABP
1400
ml
-1
biogas *g TS
1200
1000
800
600
400
200
0
0
10
20
30
40
50
60
70
80
90 100
days
It is a good test but it requires time ( 60 dd).
F. Adani, January 24-25
Anaerobic test (ABP)
600
500
646 ± 76
400
ABP m
3
biogas g
-1
TS
700
300
200
221 ± 56
100
0
Ingestates
F. Adani, January 24-25
Digestates
Aerobic test: liquid state
respiration index (SOUR)
OD Cumulata
600
Cumulated O2 up-take in
20h
500
OD
400
300
200
100
0
00:00
02:24
04:48
07:12
09:36
12:00
14:24
16:48
tempo prova
…..it allows a strong time reduction (20h)
F. Adani, January 24-25
19:12
Aerobic test
OD20 mgO2 g
-1
TS
250
200
150
219 ± 60
100
90 ± 28
50
0
Ingestates
F. Adani, January 24-25
Digestates
A case study……….
1000
ingestati
ABP (NmL gTS-1)
y = 2.319x + 73.760
R2 = 0.713
800
600
digestati
400
200
0
0
50
100
150
200
OD20 (mgO2 gTS-1)
F. Adani, January 24-25
250
300
350
-1
ABP (NmL gTS )
Correlation ABP vs SOUR
1800
1600
1400
1200
1000
800
600
400
200
0
R2 = 0.710
0
100
200
300
OD20 (mg O2 gTS )
F. Adani, January 24-25
400
500
OM quality
 Wet
analyses
 Spectroscopic
analyses
F. Adani, January 24-25
OM quality
Macromolecular composition
CS (%TS)
cell soluble
70-90%
40-70%
F. Adani, January 24-25
OM quality
Macromolecular composition
ADL (%TS)
(Lignin, cutin,
suberan, sterol)
2-8%
10-35%
effetto concentrazione
F. Adani, January 24-25
OM quality
CPMAS 13C NMR Spectroscopy
Ingestate
Digestate
F. Adani, January 24-25
Pig slurry
Digested Pig slurry
F. Adani, January 24-25
OM quality
PCA analysis
F. Adani, January 24-25
OM quality
PCA analysis
1.5
Biosolid
1.
Predig.
swine
manure
Fact.2 31.9%
.5
Fresh
swine
manure
Digestate
.
-1.
-.5
.
.5
1.
-.5
1.5
2.
Ingestate
Ingenstate
-1.
Compost
-1.5
-2.
Fact.1
+
63.8%
Biological stability
F. Adani, January 24-25
-
Nutrients: quantity
Total N (% TS)
2-5%
5-12%
F. Adani, January 24-25
Nutrients: quality
N-NH4 (% TS)
0-2%
2-8%
F. Adani, January 24-25
Nutrients: quality
Organic N
Costante 2-4%
Recalcitrant???
F. Adani, January 24-25
Xenobiotic
Heavy metals
Example of digestate analysis:
Elemento
Metal
Value
Bio solid limit Compost limits
Cd (mg/kg s.s.)
0.21
20
1.5
Hg (mg/kg s.s.)
1.19
10
1.5
Ni (mg/kg s.s.)
12.48
300
100
Pb (mg/kg s.s.)
18.16
750
140
Cu (mg/kg s.s.)
49.58
1000
230
Zn (mg/kg s.s.)
74.83
2500
500
Cr III (mg/kg s.s.)
1.16
750
-
As (mg/kg s.s.)
0.05
10
-
10
0.5
Cr VI (mg/kg s.s.)
0.08 24-25
F. Adani, January
Hygienic parameters
Parameter
Digestate Legge 99/92 Reg. CE 1774/02
Fecal coliform (MPN/g TS)
Vital Helminthes eggs
100
10.000
n.i.
Absent
Absent
n.i.
absent
Salmonella
Absent
< 100
Absent
Escherichia coli
Absent
n.i.
< 1000
n.i. = not indicated
F. 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 24-25
Digestate: the Identikit
Amendment properties
Fertilizer properties
High quality
Hygienic product
F. Adani, January 24-25
Digestate needs to be
qualified……….
F. Adani, January 24-25
….… a proposal
1. Environmental
and human protection:
Limits needed for:
 Biological
stability
 Hygienic parameters
 Heavy metal contents
F. Adani, January 24-25
..…. a proposal
2. Agronomic use:
Parameters should be indicated:





N-tot and N-NH4;
P;
K;
OM.
Moisture content
F. Adani, January 24-25
Thank you
Dipartimento di Produzione
Vegetale
Università degli Studi di Milano
F. Adani, January 24-25