Acceptance at landfills and process optimization: the importance of a consistent approach. Federico Valentini

Transcription

1 Acceptance at landfills and process optimization: the importance of a consistent approach Federico Valentini

2 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

3 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

4 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

5 Mechanical Biological Treatment PICHLER, 1999

6 Flexibility is the key word 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) Perugia 1986 Perugia 2000

7 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?

8 What pre-treatment is needed for? Art. 1 - Directive 1999/31/EC to prevent or reduce as far as possible negative effects on the environment Biogas (GHG) Leachate (DOC)

9 Biological treatment and leachate quality From Adani et al, 2003

10 Biological treatment and leachate quality From Binner, 2002

11 Defining the threshold and how to measure it Gas generation test

12 The rational for different limit values 80% reduction 90% reduction From Binner, 2002

13 RESPIROMETRY 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

14 RESPIROMETRY/BIOGAS PRODUCTION from J. Heerenklage, R. Stegmann, ORBIT 2006

15 Definition of ACCEPTANCE of MBT-treated materials at landfills Germany VS < 5% (TASi = Technical Directive on Residential Waste) only incineration is suitable AT 4 < 5 mgo 2 /g d.m. (Ablagerungsverordnung, Jan 01) ( equivalency of MBT) Austria (Deponieverordnung) Italy AT 4 < 7 mgo 2 /g d.m. DRI < 1000 mgo 2 /kgvs.h

16 Definition of ACCEPTANCE of MBT-treated materials at landfills Germany VS < 5% (TASi = Technical Directive on Residential Waste) only incineration is suitable AT 4 < 5 mgo 2 /g d.m. (Ablagerungsverordnung, Jan 01) ( equivalency of MBT) Austria (Deponieverordnung) Italy AT 4 < 7 mgo 2 /g d.m. DRI < 1000 mgo 2 /kgvs.h

17 Definition of ACCEPTANCE of MBT-treated materials at landfills Germany VS < 5% (TASi = Technical Directive on Residential Waste) only incineration is suitable AT 4 < 5 mgo 2 /g d.m. (Ablagerungsverordnung, Jan 01) ( equivalency of MBT) Austria (Deponieverordnung) Italy AT 4 < 7 mgo 2 /g d.m. DRI < 1000 mgo 2 /kgvs.h

18 Definition of ACCEPTANCE of MBT-treated materials at landfills Germany VS < 5% (TASi = Technical Directive on Residential Waste) only incineration is suitable AT 4 < 5 mgo 2 /g d.m. (Ablagerungsverordnung, Jan 01) ( equivalency of MBT) Austria (Deponieverordnung) Italy AT 4 < 7 mgo 2 /g d.m. DRI < 1000 mgo 2 /kgvs.h

19 Definition of ACCEPTANCE of MBT-treated materials at landfills Germany VS < 5% (TASi = Technical Directive on Residential Waste) only incineration is suitable AT 4 < 5 mgo 2 /g d.m. (Ablagerungsverordnung, Jan 01) ( equivalency of MBT) Austria (Deponieverordnung) Italy AT 4 < 7 mgo 2 /g d.m. DRI < 1000 mgo 2 /kgvs.h

20 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 mass balance of biodegradability LATS (UK) allows for optimised combination of strategies

21 On the acceptance of waste at landfills: the case of Italy COUNCIL DECISION of 19 December 2002 establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of 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 )

22 COUNCIL DECISION 2003/33/EC

23 COUNCIL DECISION 2003/33/EC

24 DECRETO 3 agosto 2005

25 DECRETO 3 agosto 2005

26 Some more words on respirometry

27 Different approaches: solid state Static or dynamic? Otpimal respiration rate Oxygen transfer as a limiting factor Adani e Tambone (1998)

28 Static Respiration Index (SRI) IPLA Method (Piedmont Region, 1998) P L. Paradisi 2006

29 DYNAMIC RESPIRATION INDEX (DRI) Metodo DIPROVE (Adani et al., 2001)

30 DYNAMIC RESPIRATION INDEX (DRI)

31 Different approaches: liquid state Specific Oxygen Uptake Rate (SOUR) (Lasaridi & Stentiford, 1998) Interface (A/D) & controller DO meters Fish tank pumps Water bath, 30 o C O 2 probe Compost suspension

32 Specific Oxygen Uptake Rate mg O 2 / g VS/ hr SOUR TOD Time (hours)

33 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)

34 MBT samples 1st process DRI - SRI (mg O2 / kg VS / h) SOUR (mg O2 / kg VS / h) DRI SRI SOUR 0 BT-1-b BT-1-m BT-1-e 0

35 MBT samples 2nd process DRI - SRI (mg O2 / kg VS / h) SOUR (mg O2 / kg VS / h) DRI SRI SOUR 0 BT-2-b BT-2-m BT-2-e 0

36 Biodrying samples 1st process BS-1-b BS-1-e DRI SRI SOUR

37 Biodrying samples 2nd process DRI SRI SOUR BS-2-b BS-2-e 0

38 Correlation - all data (including DOCdissolved organic carbon - fractions) DRI 1 SRI 0.78* 1 DRI SRI SOUR DOC DOC SOUR 0.70* 0.55* 1 DOC h. phylic * 1 h. philic h. phobic DOC h. phobic

39 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.

40 Grazie!