Lecture 3 Characterization and Composition of MSW

7/24/2019 Lecture 3 Characterization and Composition of MSW

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SBT 4635

Waste Management and Usage : Characterization of SolidWaste

Photo credit to ecoideal.com.my


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Objectives

!

Determine why quantification andcharacterization of MSW is important

! Understand the methodology used toquantify MSW

! Explain why it is important to characterize

MSW.

! Become familiar with MSW descriptors.

! Describe the physical, chemical, and biological

properties associated with MSW.

!

Perform calculations using waste compositionand properties.


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Why reliable data on waste compositionand quantities are essential?


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Why reliable data on waste composition andquantities are essential?

Recycling

Material recovery facilities/ incinerator

Waste as fuel

Leachate composition and treatment

Transportation

Combustion characteristics

Processing requirements

Landfill lifetime


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Composition studies

!

Direct sampling! Material flows

! Surveys

! Multipliers for projecting waste quantities


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Direct sampling

!

Useful on small scale! Involves physical sampling and sorting MSW at the source

of generation

! Accurate judgements

!

conduct at several randomly selected locations within thecommunity

! Different locations-single and multifamily homes, commercialestablishments, institutions

! @ direct sampling at centralized tipping point (transfer

station! ASTM method D5231- sample size 91-136kg


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Direct sampling

!

Disadvantage! Limited number of samples

! Misleading data-unexpected circumstances such as severe wet

or dry season.

! Did not provide accurate information about trends-unless

consistent sampling over a long period of time


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Direct sampling protocol

!

Vehicle Unloading! Sample Selection and Retrieval

! Container Preparation

! Sample Placement

!

Sorting


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Direct sampling


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Material flows

!

Useful (waste composition and trends) for regional basis! Based on production data (by weight) for materials and

products

! Oversimplification, need to consider that the communityis an open system having numerous imports and exports


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Surveys

!

Distributing questionnaires to waste producers! Detailed questions

! Quantities

! Composition-category

! Others- seasonal variation of waste generation, recycling

program

! Disadvantage

! no accurate record

! Companys confidential data


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Multipliers

!

Use to estimate waste quantities from sources in aparticular region

! Value of multipliers-based on surveys, published data anddirect sampling for an area. E.g population size, numberand type of livestock, number of employees

! The value varied widely. Estimate of households wasteproduction based on per capita generation.


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Chemical composition of waste

!

Ultimate analysis! Proximate analysis

! Energy content

! Fusion point of ash

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Content of nutrients and other substrate! Carbohydrates

! Crude fibers

! Proteins

!

Lipids! Biodegradability


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Ultimate analysis

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Total elemental analysis! % of molecular composition (C, H, N, O, P, etc.) of the

organic fraction

! The oxygen value is calculated by subtracting the othercomponents including ash and moisture, from 100%

! Usage -

! Waste as fuel

! Emission from combustion

! Suitable nutrient ratios (e.g., C/N) for biological conversion -

composting


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Physical properties of MSW

!

Density! Moisture content

! Particle size distribution

! Field capacity

!

Hydraulic conductivity

Lecture 3 Characterization and Composition of MSW

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