International SymposiumO W t M h iOn Waste Mechanics

Session A2:W t Ch t i ti P dWaste Characterisation Procedures

Neil Dixon

Aim of the sessionAim of the session• To develop a set of consensus guidelines and

recommendations for characterisation of wasteUses: To consider the uses of a waste characterisation procedure

Factors: To identify the key factors that should be included in a characterisation system

Procedure: To determine the methods that should be used to obtain information

Presentation: To determine the best approach to

2present characterisation information

The needThe needA waste characterisation procedure is required to:

• Group wastes with similar physical properties and behaviour;

• Facilitate the exchange and interpretation of measured properties; p p ;

• Help explain mechanical behaviour of waste bodies (e g compressibility and stability); andbodies (e.g. compressibility and stability); and

• Aid development of a unified framework for waste

3mechanics

DiscussionDiscussion

• Uses of characterisation• Uses of characterisation

• Key factors to be includedy

• Procedure for characterisation

• Presentation of information

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ScopeScope

• Must be useful for:Must be useful for:

Designers using anticipated waste type

Investigation of site materials

Research

• Aim is to relate classification to broad categories of engineering behaviour (like soil systems)of engineering behaviour (like soil systems), BUT this will require a body of research

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UsesUses

• Aspects of behaviourAspects of behaviour

Shear behaviour

Volume change

Hydraulic

(degradation potential)

• Process is time independent• Process is time independent

• Classification is time dependent

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Key factors - MaterialKey factors Material

• Component size distributionComponent size distribution

• Component

Material type

Shape relatedS ape e a ed

Degradation potential

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Key factors - StateKey factors State

• DensityDensity

• Structure (at all scales)

• Stress history

• Moisture content• Moisture content

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SizeSize

• Use of sieved material to separate fine fractionUse of sieved material to separate fine fraction and large fraction

( )Less than say 20mm (size to be agreed) – how much degradable material?

Assessed like soil

Greater than say 20mm, measure grading and shape related properties

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Shape relatedShape related

• Reinforcing: foils 2D and bars etc 2DReinforcing: foils 2D and bars etc 2D

• Compressible 3D components?

Compressible particles may not be present in all wastes (makes classification simpler)

Need to define compressibility potential

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Key factors - DegradabilityKey factors Degradability

• Simple visual system classification based onSimple visual system classification based on material groups vs. quantitative test (e.g. loss of ignition)g t o )

• Best practice (commercial) vs. research requirementsrequirements

• Visual for large component sizes

• Test for small component sizes (e.g. loss of ignition)

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Degradation potentialLandva and Clark (1990)

Degradation potentialLandva and Clark (1990)

Organic Inorganic

Putrescible Non-putrescible(monomers and low (highly resistant

g g

Degradable Non-degradableresistance polymers, readily biodegradable)

polymers, slowly biodegradable)

Food waste Paper Metals Glass, CeramicsGarden waste Wood Mineral soil Rubble(corrodible to varying

Degradable Non-degradable

Garden waste Wood Mineral soil, RubbleAnimal waste Textiles Tailings, Slimes

Leather AshPlastic, Rubber Concrete, MasonryPaint, Oil, Grease, Chemicals Organic

(Construction debris)

(corrodible to varying degrees)

Material contaminated by such waste

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Chemicals, Organic Sludge

The futureThe future

• ConsensusConsensus

Material groups

Sieve size (e.g. 20mm)

Method for assessing degradation potential

Shape related subdivisions• How to size foils?• How to assess compressibility potential

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Elements of a classification (Dixon & Langer 2006)

• Material groups (metal, plastics, paper, etc.)• Shape-related subdivision of waste

(i ibl ibl dcomponents (incompressible, compressible and reinforcing components)Si f t t ( di f th• Size of waste components (grading of the material groups within each shape-related subdivision)subdivision)

• Degradation potential within the material groups

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g p

Application of classificationApplication of classification• Classification of waste material will change with

time:

Initial including component modification byInitial, including component modification by treatment (i.e. state on delivery to landfill)

Short term controlled by stress state (i eShort-term controlled by stress state (i.e. compaction during placement and increasing overburden will modify deformable components)y p )

Intermediate controlled by water content, creep and degree of component degradation

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degree of component degradation

Long-term due to degradation (and creep)

ProcedureProcedureSize-dependent Decision

about Mechanical

Review reinforcing

about Mechanical Function of Components

reinforcing shape-related subdivisions based on size information

Subdivide components in each material

group into shape related

Sort into material groupsW t

Size components Classification

Assess degradation potential of shape-related

subdivisions (e.g.

reinforcing, compressible,

incompressible)

groups based on

engineering properties

Waste Components

components and produce

gradingsof

components

pcomponents

in each material group

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incompressible)

Demonstration

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Example Data (from Kölsch, 1996)p

Incompressible C t

Compressible Components

70%

80%

90%

100%

cent

age]

70%

80%

90%

100%Paper/cardboard

Flexible plastics

Rigid plastics Perc

enta

ge]

Components

80%

90%

100%

enta

ge]

80%

90%

100%Metals

Minerals rcen

tage

]

20%

30%

40%

50%

60%

70%

ing

[Dry

Mas

s Pe

rc

20%

30%

40%

50%

60%

70%g p

Organics

Miscellaneous

Inorganic/Inert

Degradable Organic Content

abili

ty [D

ry M

ass

P

30%

40%

50%

60%

70%

g [D

ry M

ass

Perc

e

30%

40%

50%

60%

70%Wood/leather

Miscellaneous

Inorganic/Inert

Degradable Organic Content

bilit

y [D

ry M

ass

Per

0%

10%

20%

0.1 1 10 100 1000 10000

Particle Size [mm]

Gra

di

0%

10%

20%Compressible Components,accumulated

Deg

rada

0%

10%

20%

0.1 1 10 100 1000 10000

Particle Size [mm]

Gra

ding

0%

10%

20%IncompressibleComponents, accumulated

Deg

rada

b

80%

90%

100%

tage

]80%

90%

100%Paper/cardboard

Flexible plastics

cent

age]

Reinforcing Components 30%

40%

50%

60%

70%

80%

[Dry

Mas

s Pe

rcen

30%

40%

50%

60%

70%

80%Rigid plastics

Metals

Minerals

Wood/leather

Inorganic/Inert ity [D

ry M

ass

Perc

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Components

0%

10%

20%

30%

0.1 1 10 100 1000 10000

Particle Size [mm]

Gra

ding

0%

10%

20%

30%g

Degradable OrganicContentReinforcing Components,accumulated

Deg

rada

bili

Classification framework

[%]

R

0

10010

Classification using three shape-related

Dry

Mas

s [ Reinforci

90

803020

0 psub-divisions

State after PlacementFinal State

ible

by

Dr

cing by Dr

50

50

70

60

40 Three states are shown: initial, after placement and final

Initial Statef

ompr

essi

b Dry Mass [

50

40

30

7060

Inco

[%]

100

20

10

9080

190 10 20 30 40 50 60 70 80 90 100

Compressible by Dry Mass [%]

00

0

Alternative method of presentation

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ScopeScope• Characterisation of components

Size

ShapeShape

Material type and engineering properties

Moisture content and history

Stress history

Degradation potential and rate

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Scope (cont )Scope (cont.)

• Ch t i ti f• Characterisation of mass

Density

Structure of components

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Further informationFurther information

• A summary of existing classifications and a fullA summary of existing classifications and a full description of the system outlined here can be found in Waste Management (Dixon & Langerfound in Waste Management (Dixon & Langer 2006)

• Any additional documents?

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