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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 RCRA Subtitle-D Wastes? • Organic • Inorganic • Putrescible • Combustible • Recyclable • Hazardous • Infectious
Terminology Generated Waste = Disposed (Collected) Waste + Diverted Waste
Importance of Generation Rates • Compliance with Federal/state diversion requirements • Equipment selection, • Collection and management decisions • Facilities design
Landfills Recycle Incineration
Source reduction/recycling Geographic location Season Home food waste grinders Collection Frequency GNP trend Population increase Legislation Public attitudes Per capita income Size of households Population density Pay As You Throw Programs Factors affecting generation Rates
Methodology Development • 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
Each load is separated manually by component example - Wood, concrete, plastic, metal, etc.
Data Interpretation • Weighted Average based on Generator Source Composition/Distribution • Contamination Adjustment
Specific Weight • Values - 600-900 lb/yd3 as delivered • Function of location, season, storage time, equipment used, processing (compaction, shredding, etc.)
Moisture content (MC) • Weight or volume based • Weight: wt. of water/sample wt. • MCwet= water/(water+solids) • MCdry= water/solids • Volume: vol. of water/sample volume
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 105 C) • Volatile Combustible Matter (VCM) (temp increased to 950 C, closed crucible) • Fixed Carbon (residue from VCM) • Ash (temp = 950 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