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Role and goals for MBT in Role and goals for MBT in strategies for the management of strategies for the management of
biodegradable wastebiodegradable waste
Enzo Favoino
Scuola Agraria del Parco di Monza
The The regulatoryregulatory contextcontext: : driversdriversfromfrom EU EU envenv policypolicy
•• LandfillLandfill DirectiveDirective �� diversiondiversion targetstargets forfor biodegbiodeg
wastewaste + + oligationoligation forfor pretreatmentpretreatment
•• RevisedRevised WFD WFD �� wastewaste hierarchyhierarchy + + recyclingrecycling
targetstargets + + preventionprevention programmesprogrammes
•• Packaging Packaging DirectiveDirective �� recyclingrecycling targetstargets
DifferentDifferent strategiesstrategies(EC Report on National (EC Report on National StrategiesStrategies forfor diversiondiversion of BMW)of BMW)
•• Austria Austria
–– 1 Jan 95 1 Jan 95 BioAbfVBioAbfV
•• Obligation to collect separately or compost at home Obligation to collect separately or compost at home
•• 500.000 ton composted in 2001500.000 ton composted in 2001
–– 1993 Packaging Ordinance 1993 Packaging Ordinance
•• Obligation to collect separately, reuse and recycle Obligation to collect separately, reuse and recycle
•• 510.000 ton of waste paper recycled in 2002510.000 ton of waste paper recycled in 2002
–– Target for 2016 already fulfilled in 2001 Target for 2016 already fulfilled in 2001
–– 1 Jan 04 1 Jan 04 DeponieverordnungDeponieverordnung
•• 5% VS or 5% VS or
•• MBT MBT �� AT4 < 7AT4 < 7
DifferentDifferent strategiesstrategies(EC Report on National (EC Report on National StrategiesStrategies forfor diversiondiversion of BMW)of BMW)
•• DenmarkDenmark
–– 27 27 JuneJune 2000 2000 OrdinanceOrdinance 619 619
•• Obligation to incinerate Obligation to incinerate ““waste suitable for waste suitable for energy recoveryenergy recovery””
–– In 2002 35.000 ton of BMW In 2002 35.000 ton of BMW landfilledlandfilled(1.813.000 in 1995)(1.813.000 in 1995)
Yes, Yes, wewe can!can!
SentSent toto recyclingrecycling
residualsresiduals
SepSep collectioncollection and and residualresidual wastewaste 20002000--2007 2007 (kg/inh.*year)(kg/inh.*year)
AlsoAlso: : dramaticdramatic changechange in in compositioncomposition ofof residualsresiduals
39,02% 13,45% 9,19% 4,20%0,00%
5,00%
10,00%
15,00%
20,00%
25,00%
30,00%
35,00%
40,00%
45,00%
50,00%
MEDIA PRIULA anno 2000 MEDIA PRIULA anno 2002 MEDIA PRIULA anno 2003 PRIULA anno 2007
PrinciplesPrinciples forfor properproper longlong--termtermwastewaste planningplanning
•• Investigate Investigate potentialpotential of of
recyclingrecycling//compostingcomposting
•• AvoidAvoid overover--sizingsizing of of capacitiescapacities forfor
treatment of treatment of residualsresiduals
•• WhereverWherever stepssteps forwardforward are are stillstill toto bebe
takentaken �� choosechoose FLEXIBILITY FLEXIBILITY
The The LandfillLandfill DirectiveDirective ,99/31,99/31
•• mandatesmandates reductionreduction ofof biodegradablebiodegradablemunicipalmunicipal wastewaste toto bebe landfilledlandfilled
•• AlsoAlso, , itit mandatesmandates pretreatmentpretreatment of the waste of the waste toto bebe landfilledlandfilled
MECHANICALMECHANICAL--BIOLOGICAL TREATMENT (MBT)BIOLOGICAL TREATMENT (MBT)
•• ReducesReduces fermentabilityfermentability �� end end materialsmaterials maymay bebeconsideredconsidered notnot ““biodegradablebiodegradable””
•• NotNot so much capitalso much capital--intensive intensive
–– Low throughputs possibleLow throughputs possible
•• High High flexibilityflexibility �� allowsallows the the growthgrowth of of recyclingrecyclingin timein time
•• May May bebe turnedturned intointo compostingcomposting at a at a laterlater stagestage
–– DoubleDouble--dutyduty sitessites (MBT + (MBT + compostingcomposting))
Constant throughput
Constant overallthroughput
Flexible system
Mass-burn
Biologicaltreatment
MBT
composting
Strategies for the treatment of Residual Waste
WhatWhat isis leftleft in in residualsresiduals? ? Prov. Lucca Capannori
Categorie merceologiche % (peso/peso) % (peso/peso) 20%
Materiale organico da cucina; 25,12% 14,84% 2,97%Materiale organico da giardino; 9,16% 4,36% 0,87%Giornali (quotidiani e riviste); 5,09% 0,95% 0,19%Cartone ondulato; 6,12% 0,06% 0,01%Cartone teso; 2,49% 0,27% 0,05%Imballaggi cellulosici poliaccoppiati; 0,98% 1,46% 0,29%Altra carta (non imballaggio e nongiornali e riviste); 5,68% 9,77% 1,95%Imballaggi flessibili in alluminio; 0,28% 1,07% 0,21%Imballaggi rigidi in alluminio; 1,00% 0,00% 0,00%Imballaggi in acciaio; 1,20% 9,35% 1,87%vetro; 2,11% 1,26% 0,25%Imballaggi flessibili in plastica; 8,76% 1,60% 0,32%
Imballaggi rigidi in plastica (bottiglie e flaconi);2,08% 0,61% 0,12%Imballaggi rigidi in plastica (nonbottiglie e flaconi); 1,96% 1,17% 0,23%
Imballaggi poliaccoppiati in plastica; 0,64% 1,91% 0,38%Altra plastica: sacchi neri; 4,83% 0,61% 0,12%Altra plastica: non imballo; 2,88% 8,05% 1,61%Imballaggi in legno; 0,72% 5,75% 1,15%Tessili e cuoio; 9,08% 17,30% 3,46%Materiali inerti, 0,22% 2,64% 0,53%Pannolini; 6,07% 13,65% 2,73%RUP; 0,30% 0,30% 0,06%Sottovaglio < 20mm. 3,25% 3,05% 0,61%TOTALE 100% 100% 20,00%
15% 15% plasticsplastics
organics
organics
nappies
nappies
15% 15% paperpaper
General MBT General MBT compliantcompliant conceptsconcepts
MSW (100%)
Mechanical / Physical
Aerobic / Anaerobic
Mechanical / Physical
35% SRF
4% metals
21% mass loss
40% [15%] Landfill
[25%] CLO
MSW (100%)
Mechanical / Physical
Drying
Mechanical / Physical
55% SRF
4% metals
30% mass loss
11% Landfill
BiodryingBiostabilisation
Basic Basic flowflow--sheetsheetSplittingSplitting of of residualresidual wastewaste
Residualwaste
Screening
Small size materials(high moisture; high fermentability)
Biologicalstabilisation
Water + CO2
Stabilised waste
Coarse materials(low moisture, low fermentability
Landfilling
Feature Final outcome % reduction (as compared to
starting conditions) Respiration rate
5 mg O2/g d.m. (96 h)
about 400 mg O2/kg VS.h
80-90 %
COD, total N in leachate
< 1000 mg/l < 200 mg/l
about 90%
Gas production
20-40 l/kg d.m. 80-90%
Volume final density (compacted): 1.2-1.4 ton/m3 mass loss (due to mineralisation): 20-40%
up to 60%
Effects of biological treatment
**
**
Basic Basic flowflow--sheetsheetSplittingSplitting of of residualresidual wastewaste
Residualwaste
Screening
Small size materials(high moisture; high fermentability)
Biologicalstabilisation
RDF
Water + CO2
Stabilised waste
Coarse materials(low moisture, low fermentability
Density refiner
rejects
Density refinerScreen
““compostcompost”” forfor
restrictedrestricted
applicationapplication??
ConceptsConcepts forfor safesafe applicationapplication
•• Biowaste compost Biowaste compost remarkablyremarkably betterbetter, on the , on the averageaverage, , thanthan mixedmixedMSW compostMSW compost
–– NotNot onlyonly glassglass and and plasticsplastics
–– HeavyHeavy metalsmetals sometimessometimes ““diluteddiluted”” in in freshfresh compost compost byby high OM high OM contentscontents
–– POPsPOPs !!!!
•• VerifyVerify the timethe time--profile of profile of accumulationaccumulation
–– Does it provide for a reasonable time frame to address the issuDoes it provide for a reasonable time frame to address the issue at e at source?source?
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0 100 200 300 400 500 600 700
years
mg
/ kg
dm
CADMIUM: Accumulation in the SOILCADMIUM: Accumulation in the SOIL(BWC: 8 t dm/ha*a; MSWC: 20 t dm/ha*3a)
BWC: 0.65 mg/kg dmGuide value
Background
deposition
MSW
C: 2.7
mg/
kg d
m
ReasonsReasons forfor developmentdevelopment of MBT of MBT
•• Flexibility is importantFlexibility is important–– Not much dependent on throughputsNot much dependent on throughputs
•• Same process technologies as composting/ADSame process technologies as composting/AD–– ““DoubleDouble--duty sitesduty sites””
–– Modular adaptation to increased separate collectionModular adaptation to increased separate collection
•• Fairly Good economies of scaleFairly Good economies of scale–– Suitable also at low capacities (down to a few ktpa)Suitable also at low capacities (down to a few ktpa)
–– Rural districtsRural districts
•• Delivers results (in terms of reduction of Delivers results (in terms of reduction of biodegbiodeg waste waste to landfills) in a comparatively short timeto landfills) in a comparatively short time–– Passive Passive aerationaeration, , lowlow--techtech on site MBT on site MBT maymay produce produce promptpromptimprovementimprovement ofof landfilllandfill conditionsconditions in in developingdeveloping WM WM systemssystems
BUTBUT……aa constraintconstraint……..ConditionsConditions forfor acceptanceacceptance at at landfillslandfills
•• A A fewfew CountriesCountries (D, AT, I, (D, AT, I, NLNL……) ) havehaveenactedenacted a a banban fromfrom landfillslandfills forfor highhigh--calorificcalorificvaluevalue materialsmaterials (6Mj/kg (6Mj/kg –– 13 13 MjMj/kg)/kg)
•• ThisThis isis NOT NOT stipulatedstipulated byby the the LandfillLandfillDirectiveDirective !!!!
•• HOWEVER HOWEVER –– asas long long asas wewe havehave toto complycomply……
•• ……areare therethere possibilitiespossibilities toto complycomply byby meansmeansofof furtherfurther recoveryrecovery ofof paperpaper and plastic and plastic materialsmaterials in in residualresidual wastewaste? ?
Food waste in Food waste in residualresidual wastewaste
Municipality % Food waste
Altivole 7,82
Arcade 8,24
Breda di Piave 7,61
Casale sul Sile 9,42
Castello di Godego 8,05
Cessalto 6,30
Conegliano 9,40
Cornuda 7,19
Giavera del Montello 6,88
CV = 3500CV = 3500--4500 Kcal/kg (154500 Kcal/kg (15--20 MJ/kg)20 MJ/kg)
Basic Basic flowflow--sheetsheetSplittingSplitting of of residualresidual wastewaste
Residualwaste
Screening
Small size materials(high moisture; high fermentability)
Biologicalstabilisation
Water + CO2
Stabilised waste
Coarse materials(low moisture, low fermentability
Landfilling
Basic Basic flowflow--sheetsheetSplittingSplitting of of residualresidual wastewaste
Residualwaste
Screening
Small size materials(high moisture; high fermentability)
Biologicalstabilisation
Water + CO2
Stabilised waste
Coarse materials(low moisture, low fermentability
RDF
Density refiner
rejects
Basic Basic flowflow--sheetsheetSplittingSplitting of of residualresidual wastewaste
Residualwaste
Screening
Small size materials(high moisture; high fermentability)
Biologicalstabilisation
Water + CO2
Stabilised waste
Coarse materials(low moisture, low fermentability
screening, hand and optical sorting,
extrusion
rejects
Material Material
recoveryrecovery
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