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Federico Valentini
Acceptance at landfills and process optimization:
the importance of a consistent approach
Directive 1999/31/EC (Landfill directive)
• Art. 5 - Reduction with time of biodegradable waste being landfilled (as compared to 1995)
a 25% within 5 years
a 50% within 8 years
a 65% within 15 years
• Art. 6 - Mandatory treatment of waste before landfilling
Directive 1999/31/EC (Landfill directive)
Reduction targets can be met by mean of:
�Separate collection (and recycling) of biodegradables
•May or may not be sufficient
Then, we have to treat the “residual waste” by:
�Incineration
�Mechanical Biological Treatment
Mechanical Biological Treatment
“Processing of solid wastes containing biologically degradable organic components, by means of a
combination of mechanical processes (i.e., cutting, crushing, sorting) and biological degradation
(aerobic/anaerobic)”
Outputs (and goals) of MBT can be:•Refuse Derived Fuel•Biogas (anaerobic process)•MSW Compost•Stabilized waste to be landfilled
Mechanical Biological Treatment
PICHLER, 1999
Flexibility is the key word
Perugia 1986 Perugia 2000
�MBT can adapt itself to changing contexts:� Put variable enphasys on biostabilization or on RDF production
� Switching from MSW compost to Quality compost when separate collection of organics is implemented (even gradually)
Does MBT comply with the Landfill
directive requirements?
If biological treatment is one of the possible treatment
than the question is:
when a mechanically-biologically treated waste can
be landfilled?
What pre-treatment is needed for?
Biogas (GHG)
Leachate (DOC)
Art. 1 - Directive 1999/31/EC … to prevent or reduce as far as possible negative effects on the
environment…
Biological treatment and leachate “quality”
From Adani et al, 2003
Biological treatment and leachate “quality”
From Binner, 2002
Defining the threshold and how to measure it
Gas generation test
The rational for different limit values
80% reduction
90% reduction
From Binner, 2002
It’s based on measurement of Oxygen consumption (or on Carbon dioxyde production) under AEROBIC
CONDITIONS
IT IS A DIRECT MEASUREMENT OF DEGRADATIVE ACTIVITY
&
CORRELATE QUITE WELL WITH BIOGAS FORMATION POTENTIAL
RESPIROMETRY
RESPIROMETRY/BIOGAS
PRODUCTION
from J. Heerenklage, R. Stegmann, ORBIT 2006
� Germany
� VS < 5% (TASi = Technical Directive on Residential Waste)� only
incineration is suitable
� AT4 < 5 mgO2/g d.m. (Ablagerungsverordnung, Jan 01) �(“equivalency” of MBT)
� Austria (Deponieverordnung)
� AT4 < 7 mgO2/g d.m.
� Italy
� DRI < 1000 mgO2/kgVS.h
Definition of ACCEPTANCE
of MBT-treated materials at landfills
� Germany
� VS < 5% (TASi = Technical Directive on Residential Waste)� only
incineration is suitable
� AT4 < 5 mgO2/g d.m. (Ablagerungsverordnung, Jan 01) �(“equivalency” of MBT)
� Austria (Deponieverordnung)
� AT4 < 7 mgO2/g d.m.
� Italy
� DRI < 1000 mgO2/kgVS.h
Definition of ACCEPTANCE
of MBT-treated materials at landfills
� Germany
� VS < 5% (TASi = Technical Directive on Residential Waste)� only
incineration is suitable
� AT4 < 5 mgO2/g d.m. (Ablagerungsverordnung, Jan 01) �(“equivalency” of MBT)
� Austria (Deponieverordnung)
� AT4 < 7 mgO2/g d.m.
� Italy
� DRI < 1000 mgO2/kgVS.h
Definition of ACCEPTANCE
of MBT-treated materials at landfills
� Germany
� VS < 5% (TASi = Technical Directive on Residential Waste)� only
incineration is suitable
� AT4 < 5 mgO2/g d.m. (Ablagerungsverordnung, Jan 01) �(“equivalency” of MBT)
� Austria (Deponieverordnung)
� AT4 < 7 mgO2/g d.m.
� Italy
� DRI < 1000 mgO2/kgVS.h
Definition of ACCEPTANCE
of MBT-treated materials at landfills
� Germany
� VS < 5% (TASi = Technical Directive on Residential Waste)� only
incineration is suitable
� AT4 < 5 mgO2/g d.m. (Ablagerungsverordnung, Jan 01) �(“equivalency” of MBT)
� Austria (Deponieverordnung)
� AT4 < 7 mgO2/g d.m.
� Italy
� DRI < 1000 mgO2/kgVS.h
Definition of ACCEPTANCE
of MBT-treated materials at landfills
Approaches to assess reduction of
biodeg waste through MBT
� Codified approaches:
� Threshold for acceptability (and biodegradability: GER, AUT) ⇒ not very flexible
� Threshold for biodegradability, NOT for acceptability (ITA, Guidelines for Regional Plans on diversion of BMW) so far
�� Proportionality: NO threshold, assessment of the Proportionality: NO threshold, assessment of the ““mass mass balance of biodegradabilitybalance of biodegradability”” �� LATS (UK) LATS (UK) allows for allows for optimised combination of strategiesoptimised combination of strategies
On the acceptance of waste at landfills:
the case of Italy
COUNCIL DECISIONof 19 December 2002
establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16of and Annex II to Directive 1999/31/EC
(2003/33/EC)
MINISTERO DELL'AMBIENTE E DELLA TUTELA DEL TERRITORIO DECRETO 3 agosto 2005
Definizione dei criteri di ammissibilità dei rifiuti in discarica. (GU n. 201 del 30-8-2005)
COUNCIL DECISION 2003/33/EC
COUNCIL
DECISION
2003/33/EC
DECRETO
3 agosto 2005
DECRETO 3 agosto 2005
Some more words on respirometry
Different approaches: solid state
Static or dynamic?
Adani e Tambone (1998)
Otpimal respiration Otpimal respiration
raterate
Oxygen transfer Oxygen transfer
as a limiting factoras a limiting factor
Static Respiration Index (SRI)
IPLA Method (Piedmont Region, 1998)
∆∆∆∆P
L. Paradisi 2006
DYNAMIC RESPIRATION INDEX (DRI)
Metodo DIPROVE (Adani et al., 2001)
DYNAMIC RESPIRATION INDEX (DRI)
Specific Oxygen Uptake Rate (SOUR) (Lasaridi & Stentiford, 1998)
DO metersInterface (A/D)& controller
Water bath, 30 oC
O2 probe
Compostsuspension
Fish tankpumps
Different approaches: liquid state
Specific Oxygen Uptake Rate
0
5
10
15
20
0 10 20 30 40 50
Time (hours)
mg
O2/
g V
S/ h
r
SOUR
TOD20
A COMPARATIVE STUDY
� 18 Samples
� 3 Mechanical Biological Treatment processes (BT)
�beginning (BTb), middle (BTm) and end (BTe) of process
� totale = 9 campioni
� 3 Biodrying Treatment (BS)
�Beginning (BSb) and end (BSe) of process
�Underscreen (ST) Ø < 2 cm
� total = 9 samples
Respiration Index determination: a comparative study
Adani, F., Gigliotti G., Valentini F., and Laraia R., (2003)
MBT samples – 1st process
0
500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
BT-1-b BT-1-m BT-1-e
DR
I -
SR
I (m
g O
2 /
kg V
S /
h)
0
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
18.000
SO
UR
(m
g O
2 /
kg V
S /
h)
DRI
SRI
SOUR
0
1.000
2.000
3.000
4.000
5.000
6.000
BT-2-b BT-2-m BT-2-e
DR
I -
SR
I (m
g O
2 /
kg V
S /
h)
0
2.000
4.000
6.000
8.000
10.000
12.000
14.000
16.000
SO
UR
(m
g O
2 /
kg V
S /
h)
DRI
SRI
SOUR
MBT samples – 2nd process
0
200
400
600
800
1.000
1.200
1.400
1.600
1.800
2.000
BS-1-b BS-1-e
0
1.000
2.000
3.000
4.000
5.000
6.000
DRI
SRI
SOUR
Biodrying samples – 1st process
0
200
400
600
800
1.000
1.200
1.400
1.600
1.800
2.000
BS-2-b BS-2-e
0
1.000
2.000
3.000
4.000
5.000
6.000
DRI
SRI
SOUR
Biodrying samples – 2nd process
Correlation - all data (including DOC-dissolved organic carbon - fractions)
DRI SRI SOUR DOC DOC
h. philic h. phobic
DRI 1
SRI 0.78* 1
SOUR 0.70* 0.55* 1
DOC h. phylic 0.46 0.23 0.69* 1
DOC h. phobic 0.05 0.31 0.16 0.40 1
Conclusions
�Dynamic respiration indexes (DRI) well describe biological treatment dynamics and efficiency
�SRI underestimate oxygen uptake, especially in unstable materials
�SOUR is quick and convenient but seems to be affected by the soluble fraction of organic matter.
