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RELIABLE DATA FOR WASTE MANAGEMENT
September 25-26, 2008, Vienna, Austria
New MSW sampling and characterization methodologiesg
The dry product methodPh. WAVRER - BRGM
BRGM, Orléans - FRANCE
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MSW characterization in France
A little page of history
• 1993: MODECOM™ (French MSW characterization methodology).
– Characterization made on the collection vehicle.– Mass of sample: 500 kg.
• 1993: First national campaign of MSW characterization in France, based upon MODECOM™
• 1994-1997: Development of selective collection schedules.
• 199 Ad i f h MODECOM™ h d l
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• 1997: Adaptation of the MODECOM™ methodology for the selective collection.
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MODECOM™ sampling & sorting operations
500 kg
Sample to be sorted
10 x 50 kgLotCollection vehicle
MSWSample to be sorted
EEN
ING
Coarse(> 100 mm)
Medium(20-100 mm)
Fines(8-20 mm)
(< 8 mm)Optional
1/8 sorted Sorted in integrality
ORT
ING
Categories
SCRE
Sub categories
Unsorted
Quartering
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SO
Categories Sub-categories
ANALYSES(Moisture content, LOI, heavy metals,Heating Value, organic matter, etc…)
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2 French AFNOR standards
• NF X30-413: Constitution of a sample of
Derived from the MODECOM™ methodology
household waste contained in a waste collection vehicleRules for sampling MSW from a collection vehicle.
– Sampling of 500 kg formed by ten 50 kg increments.– Random sampling.– …
• NF X30-408: Characterization of a sample of household related wasteRules for characterization of MSW.
– Characterization made on wet (raw) material.– Screening with a double-screen (20 & 100 mm) sorting
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g ( ) gtable.
– Quartering of the 20-100 mm fraction.– Etc.
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Screening with a screen sorting table
> Screening on wet t i l i dmaterial carried
out within 24 hours after sample constitution
> 100 & 20 mm round mesh
> In option, 8 mm round mesh
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round mesh
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Some problems with MODECOM™
> Moisture contents measurement> Moisture contents measurement• For each category (after sorting): take « approximately » 2/3 of the
mass to be dried from the « coarse » fraction and 1/3 from the « medium » fraction.
Low precision for the moisture contents value
> Working on raw (wet) material• Sanitary and security hazards for the operators:
Unsatisfactory working conditions for optimal sorting results
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Some problems with MODECOM™> Screening• Biased results for the screening operation: fine particles remain
t kstuck on coarse ones.• Screening depends strongly on the operator care or skill:
poor reproducibility of the screening operation.
> Categories/Sub-categories distribution• Biased results: fines particles sticking problem.p g p• Possibility of sorting errors (poor working conditions).
> Difficulty to use characterization results for some studies• For example: expert evaluation of a plant, in relation with fines
ti l ( ti l t MBT )
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particles (composting plant, MBT, …)Problem with material mass balance
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Dry product method characterization
> Based upon previous Cemagref studies(B M )(B. Morvan)
> Take into account previous MODECOM™ experience and data• In order to minimize mass to be sorted without decrease the
f th ltaccuracy of the results.
> Main objectives:• To reduce bias observed at different stages.• To improve reproducibility.• T i i i it h d f th t
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• To minimize sanitary hazards for the operator.• To obtain usable data for expert evaluation of a plant .
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Dry product method characterizationConstitution of the 500 kgMSW sample
“Oddbits”~ 30kg
Opening all garbage bags
1/4 1/4 1/4 1/4
70°C Drying
Sample to be sorted~130kg
Sorted in integrality
AFNOR X30-413
Total moisturecontent
Quartering
Coarse>100 mm
Medium20-100 mm
Fines8-20 mm
<8 mm
Unsorted500 g
Scre
enin
gng Sorted in 5 kg
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Unsorted500 g(in option)
Sort
in
Categories Sub-categories
Analyses
Sorted in integrality
5 kgsorted
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« Oddbits »
> Element carrying heterogeneity because of its:• SizeSize,• Weight,• Composition,• Etc.
For example: a big cardboard box, a big shoe, a microwave oven, paint cans, …
> « Oddbits » are fully sorted from the 500 kg> « Oddbits » are fully sorted from the 500 kg MSW sample.• Their composition will be re-integrated into the final MSW
sample composition
> The remainder of the MSW sample (without
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p (« oddbits ») is quartered in order to be scaled down to about ¼ of its initial mass
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Quartering of the sample
> Objective: to divide the initial MSW sample (without « oddbits ») while maintaining proper representativity« oddbits ») while maintaining proper representativity
> Based upon the « alternate shovel » method
• ¼ of the initial sampleis kept for the next h t i ti tcharacterization steps
• ¾ are discardedafter weighing
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Drying of the entire sample
> « Oddbits » and quartered sample are driedOddbits and quartered sample are dried during five days at 70°C
• Result:Total moisture contentof the MSW samplep
• But:Moisture contents data about categories(or sub-categories)are lost
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are lost
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Screening of the dried sample
> Use of a trommel with successively 100, 20 and (in option) 8 mm round mesh( p )
Reproducibility of the screening method
• The fine particles problem is solvedwhen screeningwhen screeningdried material
• Screening no longerdepends on the operator: improved reproducibility
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reproducibility
• No bias for the particlesize distribution
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Sorting on dry material
> According to AFNOR X30-408 standard categories g gand sub-categories (revised in 2007) :• The integrality of « oddbits » and coarse elements (>100 mm) are
sorted.• After sub-sampling, about 5 kg of medium elements (20-100 mm)
are sorted.• In option, sub-sample and sort about 500 g of fine elements (8-20 p , p g (
mm). Elements <8 mm are not sorted.
> From screening/sorting results and sampling ratios,
MSW iti d tt
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MSW composition on dry matter
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Relation between wet and dry composition
> MODECOM™:• Moisture contents per category – MSW composition on wet matter
> Dry product method:• Global moisture contents – MSW composition on dry matter
To compare previous and new data
> Mean category humidity data base> Correspondence table (ADEME-Cemagref study)
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p ( g y)
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Dry method benefits
>Clean• The operator does not touch raw (wet) waste before drying.p ( ) y g
Drying allows to reduce bad smells. Working conditions aresafer and more comfortable.
>Accurate• Sorting errors are less frequent while working on dry material.• Systematic bias due to the fine particle sticking problemSystematic bias due to the fine particle sticking problem
strongly decreases (for instance, 20% fine particles are stuck onwet plastic films against only 1% on dry ones).• The fine particles (<20 mm) content becomes representative
when using a trommel for screening.
>Faster thus less expensive
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>Faster thus less expensive• The mass of sample to sort is lower, saving labour costs.
Results are independent of the operators
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MODECOM™/dry method comparison results
% sur sec
X30 408 X30 466 X30 408 X30 466 X30 408 X30 466 X30 408 X30 466
Niort Nantes Rennes Sables O% on dry mass
X30-408 X30-466 X30-408 X30-466 X30-408 X30-466 X30-408 X30-466Putrescibles 8,2 3,5 13,0 4,2 11,2 3,7 12,9 5,4 Papiers 15,5 15,0 19,2 19,1 12,1 11,4 13,9 14,1 Carton 8,4 8,6 6,8 7,1 6,7 7,1 6,6 6,6 Complexes 4,8 3,9 1,8 1,2 2,4 1,7 3,8 2,9 Textiles 3,7 3,6 0,3 0,3 0,9 1,0 4,8 5,0 Text sanitaires 5,2 7,1 7,0 6,9 4,8 4,9 5,6 5,7 Plastiques 18,2 15,9 18,3 16,3 15,2 12,2 19,9 18,1 Combustibles 8,5 5,9 3,2 2,9 6,2 6,3 6,8 6,4
PutresciblePaperCardboardCompositeTextileSanitary textilePlasticCombustible
Verre 3,8 3,3 7,3 7,0 8,3 7,9 5,1 4,7 Métaux 10,4 9,6 3,8 3,7 3,1 2,7 2,7 2,6 Incombustibles 1,3 1,4 4,5 4,9 12,6 9,1 7,6 5,7 DMS 0,8 1,1 0,8 0,8 1,0 0,7 0,4 0,4 <20mm 11,2 20,9 13,9 25,8 15,6 31,3 9,9 22,6
GlassMetalUn-combustibleSpecial wasteFine <20 mm
Sources:
A t i f lt b t th d i diffi lt
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An accurate comparison of results between methods is difficult:• MODECOM™ strongly depends on the operators• Dry method is independent of the operators
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Outcome
> A new French AFNOR standard: X30-466• Household and related refuse — Characterization method —
Dry product analysis
> Method used for the new French national campaign of MSW characterizationca pa g o S c a acte at o• Ademe study - in progress.
> Used for plant expert evaluations• Composting plants.
No more problem with material
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• MBT plants.• Etc.
No more problem with material balance
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Outside France
> Review study• Methods for household waste composition studies
(Dahlén & Lagerkvist, 2008)• Over 20 methods for waste sampling and analysis – all on
manual sorting of wet waste
> Validated standards: ASTM D5231 92 (2003)> Validated standards: ASTM D5231-92 (2003)• Standard Test Method for Determination of the Composition
of Unprocessed Municipal Solid Waste • Sorting on wet waste
> European approach: the SWA tool
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> European approach: the SWA tool• No practical application yet?
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Thank you!
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Sampling errors, from theory
> Theory of sampling and sources of error (Gy, y p g ( y,2003)• 1. Long-range heterogeneity fluctuation error• 2. Periodic heterogeneity fluctuation error• 3. Fundamental error• 4. Grouping and segregation errorp g g g• 5. Increment delimitation error• 6. Increment extraction error• 7. Preparation error
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