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LESSON 2: CHARACTERISTICS AND QUANTITY OF MSW . Goals. Determine why quantification is important Understand the methodology used to quantify MSW Become aware of differences among global production rates Understand factors affecting waste generation rates
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Goals • Determine why quantification is important • Understand the methodology used to quantify MSW • Become aware of differences among global production rates • Understand factors affecting waste generation rates • Become familiar with per capita generation rates
Goals, Cont’d • Explain why it is important to characterize MSW. • Become familiar with MSW descriptors. • Understand the methods used to characterize MSW • Describe the physical, chemical, and biological properties associated with MSW. • Perform calculations using waste composition and properties.
MSW Household hazardous wastes Municipal sludge Non-hazardous industrial wastes Combustion ash SQG hazardous waste Construction and Demolition debris Agricultural wastes Oil and gas wastes Mining wastes RCRA Subtitle D Wastes
MSW - RCRA Definition • Durable goods • Non-durable goods • Containers/Packaging • Food wastes • Yard wastes • Miscellaneous inorganics
MSW - Textbook Definition • Mixed household waste • recyclables • household hazardous waste • commercial waste • yard waste • litter • bulky items • construction & demolitions waste
What are the sources of RCRA Subtitle-D Wastes? • Residential • Commercial • Institutional • Industrial • Agricultural • Treatment Plants • Open Areas (streets, parks, etc.)
What is the Nature of Municipal Solid Wastes? • Organic • Inorganic • Putrescible • Combustible • Recyclable • Hazardous • Infectious
Importance of Generation Rates • Compliance with Federal/state diversion requirements • Equipment selection, • Collection and management decisions • Facilities design • Methodology • Materials Flow • Load Count
Source reduction/recycling Geographic location Season Home food waste grinders Collection Frequency GNP trend, Per capita income Legislation Public attitudes Size of households Population density Pay-As-You Throw Programs Population increase Factors Affecting Generation Rates
EU Waste Generation Study • Studied correlation between waste generation and: • Population • Population density • Age distribution • Employment • GDP • Infant mortality • Life expectancy • Average household size • Unemployment • Tourism • Waste generation has grown steadily in Europe for over 20 years
Strongest Correlation • Generation increases with: • Population • Age distribution (fraction in 15-39, employment) • The rate of increase in GDP (for example Poland, Spain and Slovakia • Generation decreases with average household size • Low income areas had low amounts of plastics, paper and cardboard, but not organics
Conclusions • Continued increase in MSW generation rate is expected • Because of economic grown • Improving health • Increasing urbanization • Offset by declining percent of 15-59 year olds
Composition Studies • Materials Flow • Manual Sorting
Manual Sorting Methodology • Study Planning • Sample Plan • Sampling Procedure • Data Interpretation
Sample Plan • Load Selection • Number of Samples
Sampling Procedure • Vehicle Unloading • Sample Selection and Retrieval • Container Preparation • Sample Placement • Sorting
Waste contents are unloaded for sorting
Appropriate mass of material is selected randomly
Each load is separated manually by component example - Wood, concrete, plastic, metal, etc.
Weighted Average based on Generator Source Composition/Distribution Contamination Adjustment Data Interpretation
Terminology Generated Waste = Disposed (Collected) Waste + Diverted Waste
Specific Weight • Values: 600-900 lb/yd3 as delivered • Function of location, season, storage time, equipment used, processing (compaction, shredding, etc.)
Soil Phase Diagram Vsample=Vsolids+Vliquid+Vgas Vvoids = Vliquid + VgasWsample=Wsolids+Wliquid (Wgas~0.00)V=volume, W=weight or mass
Moisture content (MC) • Weight or volume based • Weight: wt. of water/sample wt. • MCwet= Wwater/(Wwater+Wsolids) • MCdry= Wwater/Wsolids • Volume: Vwater/Vsample
Chemical Composition • Used primarily for combustion and waste to energy (WTE) calculations but can also be used to estimate biological and chemical behaviors • Waste consists of combustible (i.e. paper) and non-combustible materials (i.e. glass)
Proximate Analysis • Loss of moisture (temp held at 105o C) • Volatile Combustible Matter (VCM) (temp increased to 950o C, closed crucible) • Fixed Carbon (residue from VCM) • Ash (temp = 950o C, open crucible)
Ultimate Analysis • Molecular composition (C, H, N, O, P, etc.) • Table in notes
Typical Data on the Ultimate Analysis - Example • Food Wastes • Carbon: 48% • Hydrogen: 6.5% • Oxygen: 37.6% • Nitrogen: 2.6% • Sulfur: 0.4% • Ash: 5%
Energy Content • Models are derived from physical composition and from ultimate analysis • Determined through lab calculations using calorimeters • Individual waste component energy contents
Empirical Equations • Modified Dulong formula (wet basis): BTU/lb = 145C +610(H2-02/8)+40S + 10N • Model based on proximate analysis Kcal/kg = 45B - 6W B = Combustible volatile matter in MSW (%) W = Water, percent weight on dry basis
Return to Home Page Last updated March 12, 2014 by Dr. Reinhart